EFFECT OF CERIUM OXIDE ON HYDROGEN PRODUCTION FROM ...

EFFECT OF CERIUM OXIDE ON HYDROGEN PRODUCTION FROM METHANOL USING COPPER-ALUMINA AND COPPER-ZINC OXIDE-ALUMINA CATALYST PREPARED BY

FLAME SPRAY PYROLYSIS

By Miss Pawinee Eamprapai

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree Master of Engineering Program in Chemical Engineering

Department of Chemical Engineering Graduate School, Silpakorn University

Academic Year 2013 Copyright of Graduate School, Silpakorn University

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EFFECT OF CERIUM OXIDE ON HYDROGEN PRODUCTION FROM METHANOL USING COPPER-ALUMINA AND COPPER-ZINC OXIDE-ALUMINA CATALYST PREPARED BY


By Miss Pawinee Eamprapai

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree Master of Engineering Program in Chemical Engineering

Department of Chemical Engineering Graduate School, Silpakorn University

Academic Year 2013 Copyright of Graduate School, Silpakorn University



ผลของซีเรียมออกไซด์ทมีีต่อปฏิกริิยาการผลติไฮโดรเจนจากเมทานอลโดยใช้ตัวเร่งปฏิกริิยาคอปเปอร์บนอลูมินาและคอปเปอร์-ซิงค์ออกไซด์บนอลูมินาซึงเตรียมโดยวธีิเฟรมสเปรย์

โดย นางสาวภาวนีิ เอยีมประไพ

วทิยานิพนธ์นีเป็นส่วนหนึงของการศึกษาตามหลกัสูตรปริญญาวศิวกรรมศาสตรมหาบัณฑิต สาขาวชิาวศิวกรรมเคมี ภาควชิาวศิวกรรมเคมี

บัณฑิตวทิยาลยั มหาวิทยาลัยศิลปากร ปีการศึกษา 2556

ลขิสิทธิของบัณฑิตวิทยาลยั มหาวทิยาลัยศิลปากร



The Graduate School, Silpakorn University has approved and accredited the Thesis title of "Effect of cerium oxide on hydrogen production from methanol using copper-alumina and copper-zinc oxide-alumina catalyst prepared by flame spray pyrolysis" submitted by Miss Pawinee Eamprapai as a partial fulfillment of the requirements for the degree of Master of Engineering in Chemical Engineering

.........................................................................

(Associate Professor Panjai Tantatsanawong, Ph.D.) Dean of Graduate School ............./.............../.............

The Thesis Advisor Assistant Professor Choowong Chaisuk, D.Eng.

The Thesis Examination Committee

...................................................Chairman (Tarawipa Puangpetch, Ph.D.) ............./.............../.............

...................................................Member (Associate Professor Joongjai Panpranot, Ph.D.) ............./.............../.............

...................................................Member (Assistant Professor Okorn Mekasuwandumrong, D.Eng.) ............./.............../.............

...................................................Member (Assistant Professor Choowong Chaisuk, D.Eng.) ............./.............../............



d

54404207 : MAJOR : CHEMICAL ENGINEERING KEY WORDS : FLAME SPRAY PYROLYSIS/ COPPER/ CERIUM/ ALUMINA/ METHANOL STEAM REFORMING

PAWINEE EAMPRAPAI : EFFECT OF CERIUM OXIDE ON HYDROGEN PRODUCTION FROM METHANOL USING COPPER-ALUMINA AND COPPER-ZINC OXIDE-ALUMINA CATALYST PREPARED BY FLAME SPRAY PYROLYSIS. THESIS ADVISOR : ASST. PROF. CHOOWONG CHAISUK, D.ENG. 93 pp.

The performance of Cu-Al2O3 and Cu-ZnO-Al2O3 catalysts with various CeO2 loading was investigated using the methanol steam reforming (MSR) at 200-350 ºC. All the catalysts were prepared by flame spray pyrolysis (FSP) method and characterized by XRD and TPR. The 20Cu-3CeO2-Al2O3 showed the highest methanol conversion and promoted hydrogen production rate. At CeO2 loading as 10 wt%, the behavior of MSR reaction could be changed which methanol conversion and hydrogen production rate were decreased. The 20Cu-10CeO2-Al2O3 catalyst exhibits the poorest performance of these catalysts with a maximum methanol conversion of 46%. The presence of CO2 byproduct indicated that the CeO2-containing catalysts favored the methanol steam reforming reaction. Addition of ZnO at low loading (1wt.%), Cu-ZnO-CeO2-Al2O3 catalyst demonstrated much better catalytic performance than those of the catalyst without CeO2 loading. On the other hand, addition of CeO2 at high ZnO loading (10wt.%) over Cu-ZnO-Al2O3 the catalyst behavior became similar to Cu-ZnO-Al2O3. Moreover, for ZnO impregnated on Cu-CeO2-Al2O3 catalysts, the methanol decomposition can be promoted more than the methanol steam reforming.

Department of Chemical Engineering Graduate School, Silpakorn University Student’s signature …………………………… Academic Year 2013 Thesis Advisor’s signature ……………………………



e

54404207 : สาขาวชิาวศิวกรรมเคมี คาํสําคญั : เฟลมสเปรยไ์พโรไลซิส/ ทองแดง/ ซีเรียม/ อะลูมินา/ปฏิกิริยารีฟอร์มมิงของเมทานอล

ดว้ยไอนาํ ภาวนีิ เอียมประไพ : ผลของซีเรียมออกไซดที์มีต่อปฏิกิริยาการผลิตไฮโดรเจนจากเมทา

นอลโดยใช้ตวัเร่งปฏิกิริยาคอปเปอร์บนอลูมินาและคอปเปอร์-ซิงค์ออกไซด์บนอลูมินาซึงเตรียมโดยวธีิเฟรมสเปรย.์ อาจารยที์ปรึกษาวทิยานิพนธ์ : ผศ.ดร.ชูวงศ ์ชยัสุข. 93 หนา้.

ประสิทธิภาพเชิงเร่งปฏิกิริยาของคอปเปอร์บนตวัรองรับอะลูมินาและคอปเปอร์-ซิงค ์ออกไซด์บนตวัรองรับอะลูมินาทีมีการเปลียนแปลงปริมาณซีเรียมออกไซด์ถูกศึกษาในปฏิกิริยารีฟอร์มมิงของเมทานอลด้วยไอนาํทีอุณหภูมิ 200-350 องศาเซลเซียส ตวัเร่งปฏิกิริยาทงัหมดถูกเตรียมดว้ยวธีิเฟลมสเปรยไ์พโรไลซิสและวเิคราะห์คุณลกัษณะดว้ยวธีิการกระเจิงของรังสีเอกซ์และการวดัการรีดิวซ์แบบโปรแกรมอุณหภูมิ ตวัเร่งปฏิกิริยา เปอร์เซ็นต์ซีเรียมออกไซด์ทีรวมกบัทองแดง 20 เปอร์เซ็นตบ์นอะลูมินาแสดงค่าการเปลียนแปลงเมทานอลสูงสุดและส่งเสริมอตัราการผลิตไฮโดรเจน ทีปริมาณซีเรียมออกไซด์เป็น 10 เปอร์เซ็นต ์พฤติกรรมของปฏิกิริยารีฟอร์มมิงของเมทานอลดว้ยไอนาํถูกเปลียนแปลงซึงค่าการเปลียนแปลงเมทานอลและอตัราการผลิตไฮโดรเจนลดลง ตวัเร่งปฏิกิริยา 10 เปอร์เซ็นตซี์เรียมออกไซด์ทีรวมกบัทองแดง 20 เปอร์เซ็นตบ์นอะลูมินาแสดงประสิทธิภาพเชิงเร่งปฏิกิริยาตาํทีสุดของตวัเร่งปฏิกิริยาเหล่านีกบัค่าการเปลียนแปลงเมทานอลสูงทีสุด 46% การมีอยูข่องคาร์บอนไดออกไซดซึ์งเป็นผลพลอยได ้ชีให้เห็นวา่ตวัเร่งปฏิกิริยาทีมีซีเรียมออกไซดเ์ป็นองคป์ระกอบสนบัสนุนปฏิกิริยารีฟอร์มมิงของเมทานอลดว้ยไอนาํ การเติมซิงค์ออกไซด์ทีปริมาณน้อย (1 เปอร์เซ็นต์) คอปเปอร์-ซิงค์ออกไซด์-ซีเรียมออกไซด์บนตวัรองรับอะลูมินาแสดงประสิทธิภาพเชิงเร่งปฏิกิริยาดีกว่าตัวเร่งปฏิกิริยาทีไม่มีปริมาณซีเรียมออกไซด์ ในทางตรงกนัขา้ม การเติมซีเรียมออกไซด์ทีปริมาณซิงค์ออกไซด์มาก (10 เปอร์เซ็นต์) บนตวัเร่งปฏิกิริยาคอปเปอร์-ซิงคอ์อกไซด์บนตวัรองรับอะลูมินามีพฤติกรรมเหมือนกบัคอปเปอร์-ซิงค์ออกไซด์บนตวัรองรับอะลูมินา มากไปกว่านัน การเคลือบฝังซิงค์ออกไซด์บนคอบเปอร์-ซีเรียมออกไซด์บนตวัรองรับอะลูมินา ส่งเสริมปฏิกิริยาดีคอมโพสิชันของเมทานอลมากกว่าปฏิกิริยารีฟอร์มมิงของเมทานอลดว้ยไอนาํ

ภาควชิาวศิวกรรมเคมี บณัฑิตวทิยาลยั มหาวทิยาลยัศิลปากร ลายมือชือนกัศึกษา……………………………………. ปีการศึกษา 2556 ลายมือชืออาจารยที์ปรึกษาวิทยานิพนธ์……………………………



f

Acknowledgements

This work was supported by the Department of Chemical Engineering, Faculty

of Engineering and Industrial Technology, Silpakorn University for this project are

thankfully admitted. In addition, I would like to thank SU Graduate school thesis

grant for the financial support.

The author thanks my advisor, Assistant Professor Dr. Choowong Chaisuk, for

valuable suggestions, useful discussions on this research to resolve this thesis

completed and thank Assistant Professor Dr. Okorn Mekasuwandumrong for

suggestions useful in my project. Moreover, I would like to thank Dr. Tarawipa

Puangpet who has been the chairman of the committee, Associate Professor Dr.

Joongjai Panpranot (members of the Center of Excellence on Catalysis and Catalytic

Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering,

Chulalongkorn University), Assistant Professor Dr. Okorn Mekasuwandumrong who

have been members of the committee.

Finally, I wish to thanks my family, my friends, member of Chemical

Engineering Reaction Laboratory at Silpakorn University for furtherance and support.



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Contents

Page

English abstract .................................................................................... d

Thai abstract .......................................................................................... e

Acknowledgments ................................................................................. f

List of tables .......................................................................................... i

List of figures ......................................................................................... j

Chapter

I Introduction .............................................................................. 1

Objective of the research ….......................................... 2

Scope of the research ...................................................... 2

II Methanol Steam Reforming ..................................................... 5

III Flame Spray Pyrolysis .............................................................. 15

IV Experiments .............................................................................. 22

Catalyst preparation ...................................................... 23

Catalyst characterization .............................................. 25

Catalyst activity of hydrogen production from methanol 26

V Results and Discussion ............................................................. 31

The physical and chemical properties of CeO2 on

Cu-Al2O3 catalysts ................................................ 31

The physical and chemical properties of CeO2 on

Cu-ZnO-Al2O3 catalysts ......................................... 47

VI Conclusions .............................................................................. 71



h

References .............................................................................. 72

Appendix .............................................................................. 80

Appendix A Calculation of catalyst preparation ........... 80

Appendix B Calculation of the crystallite size ............. 83

Appendix C Calculation for reducibility ..................... 87

Appendix D HC production ...................................... 89

Appendix E International presentation ........................ 92

Profile ..................................................................................... 93



i

List of table

Table Page

2.1 Effect of CeO2 concentration on catalytic activity....................... 14

4.1 The details of chemical used in the catalyst preparation.............. 23

4.2 The details of gases used in the catalyst activity test................... 26

4.3 The operating conditions of TCD gas chromatographs

for the catalytic activity test............................................. 28

4.4 The operating conditions of FID gas chromatographs

for the catalytic activity test............................................. 29

5.1 The crystalline size of Cu-Al2O3 catalysts................................... 33

5.2 The reducibility of Cu-Al2O3 catalysts........................................ 34

5.3 The crystalline size of Cu-CeO2-Al2O3 catalysts......................... 40

5.4 The reducibility of Cu-CeO2-Al2O3 catalysts.............................. 42

5.5 The crystalline size of Cu-ZnO-Al2O3 catalysts........................... 48

5.6 The reducibility of Cu-ZnO-Al2O3 catalysts................................ 50

5.7 The crystalline size of Cu-CeO2-Al2O3, Cu-ZnO-Al2O3 and

Cu-ZnO-CeO2-Al2O3 catalysts......................................... 55

5.8 The reducibility of Cu-ZnO-CeO2-Al2O3 catalysts...................... 57

5.9 The crystalline size of ZnO/Cu-CeO2-Al2O3 catalysts................. 64

5.10 The reducibility of ZnO/Cu-CeO2-Al2O3 catalysts....................... 65



j

List of figure

Figure Page

1.1 Various percentages of promoter were incorporated with

Cu-Al2O3 that prepared by FSP....................................... 3

1.2 Various percentages of promoter were incorporated with

Cu-ZnO-Al2O3 that prepared by FSP.............................. 4

2.1 The temperature dependence of methanol conversion and product

composition during methanol steam reforming over the

G-66 MR Cu/ZnO/Al2O3 catalyst from Sud-Chemie

(H2O/CH3OH = 1:3)........................................................ 6

2.2 Time-on-stream stability test of catalysts

(T = 260 ◦C, W/F =11 kgcat mol−1 s, S/M= 1.4 M)....... 11

2.3 Methanol steam reforming over CuO/ZnO/ZrO2/Al2O3

(40/30/20/10), CuO/ZnO/ZrO2/Al2O3 (30/40/20/10)

and G66B catalysts for 110 h on stream............................ 13

3.1 FE-SEM images and size distributions of the silver-glass

composite powders prepared from spray solutions

with 0.1M and 3 M concentrations................................. 17

3.2 The schematic diagram illustrating the formation mechanism

of the morphologies of ceria particles from the three

precursors (CeA, CeN and CeAN) by FSP and TEM

images............................................................................. 19

3.3 TEM micrographs of the NDC particles with different

diameters.......................................................................... 20

3.4 (a and c) TEM and SEM images of hollow Al2O3 nanospheres

with addition of surfactants............................................... 21



k

Figure Page

4.1 Experimental set-up scheme of flame spray pyrolysis system...... 24

4.2 Schematic diagram of the reaction and line for testing analyzed

by GC-TCD and GC-FID equipped with Porapak Q and

DB-1 column, respectively................................................ 27

5.1 XRD patterns of the Cu-Al2O3 catalysts....................................... 32

5.2 TPR profiles of Cu-Al2O3 catalysts.............................................. 33

5.3 MeOH conversion on Cu-Al2O3 catalysts in range 200-350 °C... 35

5.4 H2 production rate on Cu-Al2O3 catalysts in range 200-350 °C... 35

5.5 The H2/CO2 ratio on Cu-Al2O3 catalysts in range 275-350 °C..... 36

5.6 Pathway of reaction on Cu-Al2O3 catalysts in range 200-350 °C 37

5.7 XRD patterns of the Cu-CeO2-Al2O3 catalysts.................................. 39

5.8 TPR profiles of Cu-CeO2-Al2O3 catalysts..................................... 41

5.9 MeOH conversion on Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 43

5.10 H2 production rate on Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 43

5.11 The H2/CO2 ratio on Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 44

5.12 Pathway of reaction on Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 45

5.13 XRD patterns of the Cu-ZnO-Al2O3 catalysts..................................... 47

5.14 TPR profiles of Cu-ZnO-Al2O3 catalysts....................................... 49

5.15 MeOH conversion on Cu-ZnO-Al2O3 catalysts

in range 200-350 °C.......................................................... 51

5.16 H2 production rate on Cu-ZnO-Al2O3 catalysts

in range 200-350 °C.......................................................... 51

5.17 The H2/CO2 ratio on Cu-ZnO-Al2O3 catalysts

in range 200-350 °C.......................................................... 52

5.18 Pathway of reaction on Cu-ZnO-Al2O3 catalysts

in range 200-350 °C.......................................................... 53



l

Figure Page

5.19 XRD patterns of the Cu-ZnO-CeO2-Al2O3 catalysts........................... 54

5.20 TPR profiles of Cu-ZnO-CeO2-Al2O3 catalysts............................... 56

5.21 MeOH conversion of Cu-ZnO-Al2O3 (thin line) and

Cu-ZnO-CeO2-Al2O3 (dash line) catalysts

at ZnO as 1 wt.% in range 200-350 °C.............................. 58

5.22 H2 production rate of of Cu-ZnO-Al2O3 (thin line) and











at ZnO as 10 wt.% in range 200-350 °C............................ 60



at ZnO as 10 wt.% in range 200-350 °C............................ 60

5.27 The H2/CO2 ratio on Cu-ZnO-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 61

5.28 Pathway of reaction on Cu-ZnO-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 62

5.29 XRD patterns of the ZnO/Cu-CeO2-Al2O3 catalysts............................ 63

5.30 TPR profiles of ZnO/Cu-CeO2-Al2O3 catalysts................................ 65

5.31 MeOH conversion on ZnO/Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 67

5.32 H2 production rate on ZnO/Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 67



m

Figure Page

5.33 MeOH conversion on Cu-ZnO-CeO2-Al2O3 (thin line)

and ZnO/Cu-CeO2-Al2O3 (dash line) catalysts

in range 200-350 °C.......................................................... 68

5.34 H2 production rate on Cu-ZnO-CeO2-Al2O3 (thin line)

and ZnO/Cu-CeO2-Al2O3 (dash line) catalysts

in range 200-350 °C.......................................................... 68

5.35 The H2/CO2 ratio on ZnO/Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 69

5.36 Pathway of reaction on ZnO/Cu-CeO2-Al2O3 catalysts

in range 200-350 °C.......................................................... 70



1

CHAPTER I

INTRODUCTION

Hydrogen was recognized as an ideal fuel for power generation systems with

virtually zero emissions of air pollutants and carbon dioxide. Especially, hydrogen

produced via methanol reforming. From all methanol reforming reactions, methanol

steam reforming (MSR) produces the highest yield of hydrogen, about 75%, while

maintaining a low selectivity of CO of less than 1%. Moreover, methanol has been

recommended as the best source for hydrogen fuel among the high energy density

liquid fuels due to the high H/C ratio, relatively low boiling point and easy storing [1].

Selective methanol steam reforming is usually carried out below 300 ºC over copper

catalysts such as Cu/ZnO/Al2O3 for hydrogen production [2].

Copper based catalysts have been widely investigated for using in MSR

reaction due to their high selectivity and activity. Conventional Cu/ZnO/Al2O3

catalysts often consist of relatively large amounts of Cu and ZnO and a small amount

of Al2O3 [3]. It is generally accepted that copper dispersion plays a key role in the

catalytic performance while zinc oxide is known to improve the dispersion of Cu and

the reducibility of CuO. The addition of Al2O3 not only hindered the reducibility but

also weakened the interaction between CuO and ZnO in the catalysts. Although Al2O3

hindered the SRM reaction, an appropriate amount of it was needed to ensure the

stability and the mechanical strength of the catalysts [4].

To improve the efficiency of catalysts of the MSR reaction, several

researchers have introduced a third metallic oxide such as ZrO2, CeO2, Cr2O3, Fe2O3,

La2O3 or Y2O3, etc. can be added to improve the performance of CuO/ZnO-based and

CuO/ZnO/Al2O3-based catalysts. For example, ZrO2 addition to Cu-based alumina-

supported catalysts has been shown to increase methanol conversion and reduce CO

yields. The effects of ZrO2 on Cu-based catalysts appear to be similar to the effects of



2

ZnO in that ZrO2 improves Cu dispersion and leads to more reducible catalysts.

Addition of CeO2 to Cu/Al2O3 catalysts has also been shown to increase methanol

conversion, decrease CO selectivity and increase catalyst stability [5-6].

Therefore, we have motivated to study the addition CeO2 which as promoter

on Cu-based catalysts for testing the catalytic performance of hydrogen production

from methanol.

Objective of the Research

To study the effect of CeO2 on hydrogen production from methanol using Cu-

Al2O3 and Cu-ZnO-Al2O3 catalyst prepared by flame spray pyrolysis (FSP).

Scope of the Research

1. Catalyst preparation

All the catalysts are divided into two groups. In first group, the catalysts

containing Cu on Al2O3 supported which various percentages of copper as 10-50

wt.%. The appropriate percentage of copper was selected to promote with CeO2 using

percentages loading as 1, 3, 5 and 10 wt.%. In second group, we have studied the

effect of CeO2 promoter on Cu-ZnO-Al2O3 catalysts by percentages of CeO2 loading

was fixed. Thus, in this part, percentages of ZnO loading were various as 1, 3 and 10

wt.% to improve the catalysts. All the catalysts were prepared by flame spray

pyrolysis (FSP) which the details were shown in figure 1.1-1.2.



3

Diagrams of the catalyst preparation

First part

Figure 1.1 Various percentages of promoter were incorporated with Cu-Al2O3 that

prepared by FSP.

The loading 1 wt.% of CeO2 incorporated with Cu- Al2O3 that prepared by FSP.




Percentages of promoter

Cu-1Ce-Al Cu-3Ce-Al Cu-10Ce-Al Cu-5Ce-Al

4

Second part

Figure 1.2 Various percentages of promoter were incorporated with Cu-ZnO-

Al2O3 that prepared by FSP.

The loading 1 wt.% of ZnO incorporated with Cu-ZnO-Al2O3 that prepared by FSP.



2. Catalyst characterization

The bulk crystal structure and chemical phase composition were determined by

X-ray diffraction (XRD).

The reduction behavior of each catalyst and reducibility of catalysts were

determined by temperature programmed reduction (TPR).

3. Catalyst evaluation

The activity and production rate of all catalysts were tested at atmospheric

pressure by the H2 production from methanol in fixed-bed reactor.

Percentages of promoter

Cu-1ZnO-xCe-Al Cu-10ZnO-xCe-Al Cu-3ZnO-xCe-Al

5

CHAPTER II

METHANOL STEAM REFORMING

Hydrogen can be a major fuel to supply energy via the use of fuel cells. The

selection of the hydrogen source for a particular application depends on technical,

economic and political factors. Commercially, methanol reforming was the primary

method to produce hydrogen which can be obtained directly from methanol according

to three different reactions. There are methanol steam reforming (MSR), partial

oxidation of methanol (POM), and the decomposition of methanol (DM)

CH3OH + H2O 3H2 + CO2 (2.1)

CH3OH + 0.5O2 CO2 + 2H2 (2.2)

CH3OH 2H2 + CO (2.3)

From all methanol reforming reactions, methanol steam reforming (MSR)

produces the highest yield of hydrogen, about 75%, while maintaining a low

selectivity of CO less than 1%. Methanol is one of the most interesting hydrocarbon

sources for hydrogen production. The absence of a strong C–C bond facilitates the

reforming at low temperatures (200–300 ºC). This range of temperatures is very low

when compared to other common fuels. Although methanol is highly toxic and

miscible in water, it has the advantage of being biodegradable, liquid at atmospheric

conditions and has high hydrogen to carbon ratio [7]. Peppley et al. [8] found that the

methanol decomposition reaction occurred in parallel with the steam reforming

reaction, particularly at low conversions. In contrast, Agrell et al. [9] reported that CO

production was negligible at very short space times (low conversions) under the

conditions used in their study. Several groups had also reported that CO was a

secondary product (formed from CO2 via the reverse water-gas-shift reaction) rather

than a primary product (formed via direct methanol decomposition).

6

Production of H2 by MSR was studied in the temperature range between 175

and 350 ºC over Cu/ZnO/Al2O3 catalysts from Sud-Chemie (G-66 MR) as showed in

Figure 2.1. Methanol conversion was kinetically controlled in the lower temperature

region, whereas mass transfer limitations occurred above 220°C.

Figure 2.1 The temperature dependence of methanol conversion and product

composition during methanol steam reforming over the G-66 MR

Cu/ZnO/Al2O3 catalyst from Sud-Chemie (H2O/CH3OH = 1:3).

(Agrell et al., 2002)

Copper-based catalysts are the most commonly used for the methanol steam

reforming reaction (MSR) due to their high activity and selectivity. However, these

catalysts are known for their pyrophoric characteristics and deactivation by thermal

sintering which motivates the search for other types of catalysts. In comparison to Cu-

based, group 8–10 catalysts have been reported in the literature as highly stable and

with similar selectivity.

However, concerning the catalytic activity, the later catalysts have the

disadvantage of producing less hydrogen than the copper-based ones [10]. In this

research, we focus copper-based catalysts for the MSR reaction to enhance the

7

performance of the catalysts. Some studies are based on the addition of promoters,

while others focus on the effect of the preparation method. Catalysts for other

reactions such as partial oxidation and autothermal steam reforming are not included

in this study.

In addition to catalytic metal composition, the method of preparation had been

shown to be extremely important to catalytic performance. Several preparation

methods, including impregnation, coprecipitation, and hydrothermal synthesis, were

studied by Shen et al. [11] for methanol reforming over Cu/Zn/Al-based catalysts. It

was found that the preparation method affects conversion and selectivity. Shen and

Song examined the effect of the preparation method on the catalytic behavior of

Cu/Zn/Al catalysts and found that it significantly affected the dispersion of copper

particles and the catalyst performance in terms of methanol conversion, H2 yield and

CO concentration. A correlation between the observed catalytic activity and the

presence of highly dispersed Cu metal particles, obtained by an appropriate synthetic

procedure, was also proposed by Shishido et al. and Li et al. A very high catalytic

activity for methanol steam reforming at low temperature was reported by Zhang et al.

[12] on Cu/ZnO/Al2O3 catalysts synthesized by a gel-coprecipitation approach with

respect to the catalysts prepared by a conventional coprecipitation technique. This

superior catalytic performance was attributed not only to the generation of highly

dispersed copper and zinc components but also to the creation of catalytically actived

copper species with a much stronger Cu-Zn interaction.

Similarly, Zhang et al. attributed the better performance of a Cu/ZnO/Al2O3

catalysts obtained from a CuO/ZnO/Al2O3 sample, prepared by conventional

carbonate coprecipitation method and aged under microwave irradiation, to the

creation of highly strained copper nanocrystals in the active catalyst. Kurr et al. [13]

found that among various Cu/ZnO/Al2O3 catalysts, prepared by hydroxycarbonate

coprecipitation procedure, the catalytic activity and thermal stability under methanol

steam reforming conditions were influenced not only by the copper specific surface

area but also by defects in the bulk structure.

Jakdetchai et al. [14] improved the impregnation technique in order to achieve

higher copper dispersion in CuZn catalysts. They prepared a copper zinc-impregnated

FSM-16 (Folded Sheet Silica) catalyst by using a modified impregnation method with

8

1,3-butanediol. When compared to the catalyst prepared by the conventional wet

impregnation method, this new catalyst presented a higher copper dispersion that

enhanced methanol conversion (ca. 62% higher) and decreased selectivity (no CO

detected at 230 ºC).

Kawamura et al. [15] reported optimization of the coprecipitation temperature

and pH, important in increasing Cu dispersion. Valde´s-Solı´s et al. [16] reported

synthesis of nanosized spinel Cu-based catalysts by a silica template technique.

Compared to conventionally prepared catalysts, improved surface areas were

reported, resulting in highly active catalysts. Deactivation due to coking was

observed, although it appeared to be independent of the synthesis method.

Gold (Au) supported on CeO2-Fe2O3 catalysts prepared by the deposition-

coprecipitation technique were investigated for methanol steam reforming. C.

Pojanavaraphan et al. [17] studied the 3 wt% Au/CeO2-Fe2O3 sample achieved 100%

methanol conversion and 74% hydrogen yield due to a strong Ce-Fe interaction in the

active solid solution phase. The sintering of Au particles was observed when the

highest metal content of 5 wt% was registered, which worsened the SRM activity.

Hydrogen production by steam reforming of methanol and ethanol is studied

over a series of Cu/ZnO/Al2O3 catalysts prepared by different coprecipitation

procedures and modified with the introduction of Ni and Co. Active and cheap

catalysts, comprising based metals (Cu, Co and Ni) as active phase and ZnO as

promoter, can be prepared following simple ways, demonstrating good performances

in the hydrogen production through the steam reforming of alcohols. Lorenzut et al.

[4] studied the optimization of the preparation methodology leaded to high surface

area materials, although the metal dispersion remains quite low due to the high metal

loading. N2O decomposition experiments, XRD analysis and HR-TEM images

suggest that metal nanoparticles could be at least partially embedded into the

ZnO/Al2O3.

The performances of different xCu10Al, xZn10Al (x = 1, 3, and 5),

5%Zn5Cu10Al and 5%Cu5Zn10Al catalysts prepared by impregnation method on

methanol steam reforming (MSR) at 350 oC were investigated by M. Mrad et al. [18].

The results show that the presence of alumina enhances the dispersion of copper oxide

species by the stabilization of isolated Cu2+ ions. The impregnation of copper over

9

alumina supports shows better results than that of zinc. The presence of zinc over

alumina seems to favor the reverse water gas shift reaction. Among all the tested

series, the 5%Cu5Zn10Al shows the highest performance due to the presence of

ZnAl2O4 spinal form that stabilises the Cu+, which is the most active specie in the

SRM.

P.P.C. Udani et al. [19] studied CuO–CeO2 catalysts prepared by

coprecipitation method with varying copper content in the range of 30–80%. The

activity of CuO–CeO2 catalysts for MSR increased with the copper content and

70%CuO–CeO2 catalyst showed the best catalytic performance in the temperature

range of 160–300 oC. XRD of the used catalysts showed that the copper species after

SRM were mainly metallic copper with small amount of CuO and Cu2O, an indication

that metallic copper is an active species in the catalysis of MSR. The optimum

70%CuO–CeO2 catalyst showed stable activities for MSR reactions at 300 oC.

It was generally agreed that there was an optimum balance between metallic

Cu0 and oxidized Cu+ for maximum activity/selectivity and this was a function of not

only the catalyst preparation and composition but also the feed and reaction

conditions. It was generally accepted that copper dispersion played a key role in the

catalytic performance of these materials while the function of ZnO was to obtain and

maintain the catalytically actived copper in optimal dispersion and to improve the

reducibility of CuO. The addition of small amounts of Al2O3 further inhibited thermal

sintering of copper particles and, therefore, imparts chemical and thermal stability to

the catalyst. Moreover, it had been shown that the H2 yield decreased with increasing

alumina concentration.

S. D. Jones et al. [7] studied methanol steam reforming over nanoparticle-

supported catalysts. The catalysts achieved similar conversions as the commercial

reference catalyst but at slightly higher temperatures. Furthermore, the nanoparticle-

supported catalysts also exhibited a significantly lower CO selectivity at a given

temperature and space time than the reference catalyst. The TOF of the catalysts were

higher than that of the commercial catalyst, which means that the activity of the

surface copper is higher. Moreover, the acidity of the alumina support appears to

promote CH2O formation, which at low Cu concentrations is not reformed to CO2 and

H2.

10

Cu-based catalysts with different supports (CeO2, ZrO2 and CeO2-ZrO2) for

methanol steam reforming (MSR) were prepared by a co-precipitation procedure, and

the effect of different supports was investigated. The introduction of ZrO2 into the

catalyst improved the Cu dispersion and catalyst reducibility, while the addition of

CeO2 mainly increased oxygen storage capacity. Lei Zhang et al. [20] showed that the

CeO2-ZrO2-containing catalyst showed the best performance with lower CO

concentration, which was due to the high Cu dispersion and well oxygen storage

capacity.

Promoters have been used to influence the status of copper and enhance the

performance of the catalyst. Studies on the promotional effects of zirconia have

revealed that this structural promoter decreases the CO selectivity. For instances,

Lindström and Pettersson [21] studied the effect of zirconia in alumina-supported

monolithic Cu-Zn catalysts. Although the Zr doped catalysts were less active than the

ones without Zr, the selectivity towards CO2 was higher. Jeong et al. [22] compared

the performance of Cu/ZnO/Al2O3 to the one of Cu/ZnO/ZrO2/Al2O3, and reported an

increase of approximately 16% in methanol conversion and a CO molar fraction 7.3

times lower, due to the presence of ZrO2. Agrell et al. [23] reported an increase of ca.

37.5% in copper dispersion after adding ZrO2 to Cu/ZnO catalyst. Finally, ZrO2, as

well as ZnO, can prevent copper particles from aggregation and help stabilize the

crystal size of copper [24]. Another structural promoter is Al2O3, which provides a

larger surface on which copper can be dispersed [22, 23]. Agrell et al. [23] observed

an increase of both total surface area (48.6-91.9 m2 g−1) and copper dispersion (9.6–

11.3%) due to Al2O3. A similar effect can be attained by adding Cr2O3 [25, 26], which

acts as stabilizer of the copper structure reducing sintering. The promotional effects of

CeO2 have been described in the literature [16, 27, 28, 29], in particular, Liu et al.

reported high activity of the Cu/CeO2 catalysts compared to Cu/ZnO, Cu/Zn(Al)O and

Cu/Al2O3 with the same Cu loading and under the same reaction conditions. It was

suggested that the high activity of the Cu/CeO2 catalysts was due to the highly

dispersed Cu metal particles and the strong metal-support interaction between the Cu

metal and CeO2 support. The catalytic activity has been reported to improve with the

addition of yttria which appears to stabilize a high copper surface area [30]. P. Bichon

et al. [31] investigated Cu-based catalysts with and without Pd addition. The increase

11

in activity by adding Pd is moderate, and is accompanied by a large increase in CO

production. However, the Pd addition leads to a faster start-up without pre-reduction,

thus improving the dynamics of the system. Moreover, the addition of Pd also led to

poorer selectivity, due to a significant increase in the selectivity to CO. Finally,

Houteit et al. [32] reports that cesium oxide can prevent copper oxide crystallites from

sintering and its reduction into metallic Cu.

Figure 2.2 Time-on-stream stability test of catalysts (T = 260 ◦C, W/F =11 kgcat

mol−1 s, S/M= 1.4 M). (S. Patel and K.K. Pant, 2006)

The catalytic activity and hydrogen selectivity of cerium and zinc promoted

copper–alumina catalysts have been investigated for the selective production of

hydrogen via methanol steam reforming (MSR). Results revealed that the methanol

conversion, hydrogen selectivity and carbon monoxide formation varied with the type

of promoter and content of copper in the catalyst. S. Patel et al. [27] found cerium

promoted Cu–Zn–Ce–Al-oxide catalysts improved the activity and hydrogen

selectivity greatly and also kept the CO formation very low. Using cerium the MSR

could be carried out at lower temperature with high methanol conversion, results in

suppression of methanol decomposition and reverse water gas shift reactions

eventually end-up with the low carbon monoxide and hydrogen rich product stream.

Cerium also stabilizes the copper–alumina catalysts effectively that was confirmed by

12

deactivation studies in which cerium promoted Cu–Zn–Ce–Al-oxide catalysts gave

the consistent performance for a long run-time compared to catalysts containing only

zinc promoter as showed in Figure 2.2.

P. Clancy et al. [30] studied Cu–zirconia catalysts containing various additives

(Y2O3, La2O3, Al2O3 and CeO2) have been prepared by coprecipitation method and

their activities and stabilities under operating conditions for the methanol steam

reforming. It has been found that an yttria promoted catalyst containing 30 mol% Cu

and 20 mol% of Y2O3 is not only very active but is also very stable under reaction

conditions used. The yttria appears to stabilise a high copper surface area and may

also have a slight promotional effect on the copper. Moreover, J. Papavasiliou et al.

[28] studied doping of CuO–CeO2 catalysts with small amounts of oxides of Sm and

Zn improves their catalytic performance in methanol steam reforming, while doping

with oxides of La, Zr, Mg, Gd, Y or Ca lowers or has negligible effect on catalytic

activity. All doped catalysts produce less CO than CuO–CeO2. Addition of larger

amounts of dopant leads always to a decrease of catalytic activity. Pd and Rh-

containing catalysts have similar (Rh) or higher (Pd) activity compared to CuO–CeO2,

but their CO selectivity is significantly higher and close to WGS equilibrium.

G. Huang et al. [6] studied CuO/ZnO/CeO2/ZrO2/Al2O3 catalysts for the steam

reforming of methanol. CeO2, ZrO2 and Al2O3 all improved the dispersions of CuO

and ZnO in catalysts. ZnO and ZrO2 improved the MSR reaction, but CeO2 and Al2O3

weakened the reaction. The introduction of ZrO2 into CuO/ZnO/Al2O3 improved the

reducibility and stability of the catalyst. The addition of CeO2 or Al2O3 hindered the

reducibility of the catalyst and weakened the interaction between CuO and ZnO.

Nevertheless, an appropriate amount of Al2O3 was needed for the stability and the

mechanical strength of the catalysts. The CuO/ZnO/ZrO2/Al2O3 (40/30/20/10) catalyst

was the best one in this study.

13

Figure 2.3 Methanol steam reforming over CuO/ZnO/ZrO2/Al2O3 (40/30/20/10),

CuO/ZnO/ZrO2/Al2O3 (30/40/20/10) and G66B catalysts for 110 h on

stream. (G. Huang et al., 2009)

Effects of CeO2 content on Cu/Al2O3 catalysts prepared by co-precipitated

method were investigated. X. Zhang et al. [29] found that 20 wt% CeO2 promoted

Cu/Al2O3 catalysts exhibited higher activity and stability as compared to the

unpromoted ones. Results of XRD and the surface element distribution of catalysts

showed that CeO2 could enhance the surface dispersion of copper on catalysts, and

prevent copper crystallites from sintering and make copper crystallites relatively

smaller. It is suggested that high activity, selectivity and stability of CeO2 promoted

catalysts have been resulted from a higher copper dispersion and smaller copper

crystallites, and the synergetic effect of ceria.

14

Table 2.1

Effect of CeO2 concentration on catalytic activity

Reaction conditions: P = 0.1MPa; t = 250 ºC; X the methanol conversion; Y the

hydrogen yield; S the selectivity; and y is the outlet CO concentration. (X. Zhang et

al., 2003)

Number W (CeO2) % X (CH3OH) (mol%) Y (H2) (mol(h.g)-1) S (H2) (%) Y (CO) (mol%)

1 0 81.4 0.2509 99.7 0.37

2 5 87.5 0.2697 99.9 0.19

3 10 90.0 0.2774 99.9 0.17

4 15 93.0 0.2866 99.9 0.15

5 20 95.5 0.2944 99.9 0.14

6 25 91.8 0.2829 99.9 0.16

15

CHAPTER III


Nanotechnology has become a key area in the development of science and

engineering [33]. Nanotechnology basically involves the production or application of

materials that have unit sizes of about 10-100 nm. Comparing micron-sized and nano-

sized alumina particles, nano-alumina has many advantages. A smaller particle size

would provide a much larger surface area for molecular collisions and therefore

increase the rate of reaction, making it a better catalyst and reactant.

There are several methods to synthesize nano-alumina [34], and these are

categorized into physical and chemical methods. Physical methods include

mechanical milling, laser ablation, flame spray and thermal decomposition in plasma.

Chemical methods include sol–gel processing, solution combustion decomposition

and vapor deposition. Most of the chemical methods have resulted in extremely low

yield rates, and thus cannot be adapted to mass manufacturing. Physical methods like

mechanical milling are not efficient as the size of the nanoparticles cannot be easily

controlled, and these methods are only limited to certain materials. Other methods

such as laser ablation, vapour deposition and sol-gel are very costly as they require

specialized equipment such as vacuum systems, high power lasers as well as

expensive precursor chemicals. Finally, most systems are only possible for a specific

range of materials.

In this work, we focused on the synthesis nanoparticles by flame spray

pyrolysis (FSP), it can be seen that this method is a simple and clean method to

produce a large amount of various nanoparticles in a short time is desirable for

practical purpose. The nanoparticles products by FSP technique have shown high

surface-area and high purity. The FSP can be control characteristics for synthetic

16

nanoparticles which controlled by fuel composition, oxidant dispersion gas flow rate,

the type of oxidant dispersion gas used, production rate, precursor feed rate, precursor

concentration and the type of precursor used [35, 36, 37]. O. Mekasuwandumrong et

al. [38] studied the Pd/TiO2 nanoparticles were synthesized by flame spray pyrolysis

(FSP) under different flame condition (varying precursor concentration and the feed

flow rate). The particle size of Pd/TiO2 increased with increasing precursor

concentration and feed flow rate. The BET surface areas and percentages of anatase

phase decreased with increasing particle size of Pd/TiO2. The active sites of the

Pd/TiO2 catalysts were increased with increasing TiO2 crystallite size and Pd cluster

size. It is suggested that coverage of Pd surface by the formation of TiO2 groups

occurred more easily when the Pd/PdO2 cluster was smaller resulted from shorter

residence time in flame and lower combustion energy during FSP.

The concentrations of the spray solution were investigated by H.Y. Koo et al.

[39]. They were studied the effect of mean particle size of the silver-glass composite

powders by controlling the precursor concentrations. Figure 3.1 shows SEM images

and size distributions of the silver-glass composite powders prepared from spray

solutions with 0.1M and 3 M. The mean particle size increased from 45-75 nm with

an increase in the precursor concentration from 0.1-3 M. The mean particle size of the

powders formed by nucleation and growth mechanism increased with an increase in

the concentration of the evaporated vapors. The increase in the concentration of the

spray solution increases the concentration of the vapors inside the diffusion flame.

Therefore, the mean particle size of the composite powders increased with an increase

in the concentration of the spray solution.

17

Figure 3.1 FE-SEM images and size distributions of the silver-glass composite

powders prepared from spray solutions with 0.1 M and 3 M

concentrations. (H.Y. Koo et al., 2011)

The types of spray solution affect the formation of particle in the flame spray

pyrolysis. It was investigated by varying percentages of ethyl alcohol in the solution

was changed from 0% to 30%. The silver and glass components diluted with mixture

of ethyl alcohol and distilled water to a 0.5 M solution. The particle size of silver–

glass composite powders decreased (42 to 22 nm) with increasing percentages of ethyl

alcohol (0 to 30% EtOH). Increasing the percentages of ethyl alcohol will increase

energy to flame and synthesis zone. The higher temperature will cause agglomeration

to occur more readily, small particle resulted [40].

18

The effect of various precursors using a flame spray pyrolysis (FSP) was

investigated. Ceria particles were prepared using FSP which provided by different

cerium precursors including cerium (IV) ammonium nitrate (CeAN), cerium (III)

acetate hydrate (CeA) and cerium (III) nitrate hydrate (CeN) The morphology of the

ceria nanoparticles from CeAN, CeA and CeN precursors showed in Figure 3.2. The

ceria particles prepared from CeAN showed solid spherical due to good solubility of

CeAN in solution which the ammonium nitrate make a surfactant to form micelles.

Therefore, the ammonium nitrate and water surrounded outside of the cerium, known

as the formation mechanism of volume precipitation of cerium. The particles prepared

from CeA showed the hollow structures of open pores due to the formation of surface

precipitation before extraction of non-metallic moieties. The CeN precursor was

shown close pores of the ceria particles. Therefore, the formation of particle structures

was involved both volume precipitation and surface precipitation resulting in different

morphological ceria particles. The detail about the formation mechanism of the

morphology of ceria particles from three precursors was shown in Figure 3.2.

The nanostructures with different morphologies from flame synthesis such as

hollow spheres, core-in-shell structures and carbon tubes were investigated. F.

Krumeich [41] have prepared ZnO nanorods with control of ratio (ratio of length to

width) and vary of metal-doped (In, Sn, Li) by flame spray pyrolysis (FSP). In and Sn

dopants have effect ZnO crystal and incorporated into lattice. The ZnO particles show

rodlike shape with increasing dopant concentration of In and Sn. Moreover, the

specific surface area for In- and Sn-doped ZnO increased with dopant concentration.

The nanorod formation with In and Sn occurs by annealing crystallization during

flame cooling.

19

Figure 3.2 The schematic diagram illustrating the formation mechanism of the

morphologies of ceria particles from the three precursors (CeA, CeN

and CeAN) by FSP and TEM images. (F. Kruneich, 2006)

S.J Shih et al. [42] studied the nickel-doped ceria (NDC) nanoparticles and

yttrium-doped ceria (YDC) particles were prepared by flame spray pyrolysis. Figure

3.3 show the TEM micrographs of the NDC particles. The shapes of the particles

presented solid sphere and hollow sphere. Figure 3.3a show particles with diameters

less than ~100 nm were solid and polycrystalline. The hollow sphere showed in figure

3.3b and it clear in Figure 3.3c. The results from TEM showed that the particle

diameters were about 250 nm were prepared by FSP display hollow and rough

spherical with smooth surfaces. While the particle diameters were above 250 nm

displays uneven and concave surfaces.

20

Figure 3.3 TEM micrographs of the NDC particles with different diameters,

(a) ~30 nm, (b) ~150 nm and (c) ~250–500 nm. (S.J Shih et al., 2009)

Yanjie Hu. et al. [43] have prepared Al2O3 hollow structure by addition of

surfactants in flame spray pyrolysis. TEM and SEM image of Al2O3 hollow structure

were shown in figure 3.4. The liquid feed was mixture of hydrated aluminum nitrate

(AN) and ethanol with addition of polyethylene glycol (PEG-2000) as the surfactant.

Moreover, they have studies the molar ratio between PEG-2000 and AN was 0.02 and

0.03 which using symbol as AN-S1 and AN-S2, respectively. The liquid precursor

was fed in flame spray pyrolysis. The TEM images in Figure 3.4 (a) display the

morphology of hollow Al2O3 structure by addition of PEG-2000 and Figure 3.4 (b)

display the hollow vesicles without addition of PEG-2000. The sample shows the

hollow nanospheres is about 80 nm and shell thickness about 10 nm (Figure 3.4, f and

e). The structures of the nanospheres with and without surfactants SEM images shown

in Figure 3.4 (c) and (d), respectively. The hollow Al2O3 nanosphere without addition

of surfactants illustrates an inhomogeneous mixture of large hollow vesicles, small

21

hollow structures and solid particles. While the sample with addition of surfactants

display formation of uniform and well-spherical particles, which could have resulted

from the coalescence and of droplets with stability of the droplets, change of droplets

from initial spherical shape to regular shapes. Surfactants can be inhibiting droplets

from combination and formation of uniform particles. The TEM image of the hollow

Al2O3 of AN-S1 and AN-S2 are shown in Figure 3.4 (g) and (h), respectively. The

particle size of the hollow nanospheres decreased with increasing PEG/AN ratio.

Figure 3.4 (a and c) TEM and SEM images of hollow Al2O3 nanospheres with

addition of surfactants, (b and d) TEM and SEM images of hollow

vesicles without addition of surfactants, (e and f) HRTEM of hollow

Al2O3 nanospheres with addition of surfactants, (g) TEM image of

sample AN-S1, (h) TEM image of sample AN-S2. (Yanjie Hu et al.,

2011)

22

CHAPTER IV

EXPERIMENT

In this chapter, the details of the experimental system and procedures used in

this research are explained. These topics are classified into three sections. The

procedure for catalyst preparation by flame spray pyrolysis and wet impregnation

method are first presented in section 4.1. Subsequently, section 4.2 explains

characterization techniques including x-ray diffraction (XRD) analysis and

temperature programmed reduction (TPR). Finally, a detail procedure for catalyst

evaluation in hydrogen production from methanol is explained.

23

4.1 Catalyst Preparation

The chemicals used in this research are all analytical grades as listed in table 4.1.

Table 4.1 The details of chemical used in the catalyst preparation.

4.1.1 Preparation by flame spray pyrolysis

Copper (II) nitrate and aluminium nitrate were used as the feed precursor

which diluted in ethanol 0.5 M solution for Cu-Al2O3 based catalyst. Cerium (III)

nitrate and zinc nitrate were used as the feed precursor of promoter. The calculation of

chemical content was explained in Appendix B. The mixed of precursor and solvent

were injected through the center capillary of the FSP nozzle by a syringe pump at 5

ml/min, which was fed oxygen for dispersion of solution at 5 ml/min. The pressure

drop at the nozzles allows the synthesis was held constant at 1.5 bar by adjusting the

orifice gap area at the nozzle. The catalyst powder was collected on a glass microfiber

filter (Whatman) with the aid of a vacuum pump. The equipment of flame spray

pyrolysis system is showed in figure 4.1.

Chemicals Formula Grade (%) Manufacture

Copper (II) nitrate Cu(NO3)2.2.5H2O 99.0 Ajax Finechem Pty Ltd

Zinc nitrate Zn(NO3)2.6H2O 98.0 Ajax Finechem Pty Ltd

Aluminium nitrate Al(NO3)3.9H2O 98.0 Fluka

Cerium (III) nitrate CeN3O9.6H2O 99.0 Aldrich

Ethanol C2H5OH 99.9 SSCV Corporation

24

Figure 4.1 Experimental set-up scheme of flame spray pyrolysis system.

4.1.2 Preparation by wet impregnation

1. To prepare impregnating solution, the precursor of cerium was loading on 2

g of catalyst as explained in Appendix B. The deionized water was added in the

solution.

2. The cerium solution obtained from the first step was gradually dropped into

the catalyst using a dropper. Continuous stirring of a mixture in the flask in order to

achieve the homogeneously distributed metal component on the catalyst at 70 °C for 6

h.

3. The impregnated catalyst was dried overnight in an oven.

4. The dried sample obtained from the third step was calcined. This step was

conducted using a ceramic tube in which a ceramic boat containing the dried sample

25

was placed. This sample was heated under air at a flow rate of 30 ml/min with a

heating rate of 10 °C/min from room temperature to 350 °C and held for 5 h.

5. After the calcined sample was cooled down, it was stored in a glass bottle

for further use.

4.2 Catalyst Characterization

4.2.1 X-ray diffraction analysis

The bulk crystal structure, crystalline size, compounds and chemical phase

composition can be analyzed using X-ray diffractometer SIEMENS D-5000, X-ray

diffractometer of Ni-filtered Cu Kα connected with a computer with Diffract ZT

version 3.3 program for fully control of the XRD analyzer. The XRD patterns were

recorded in the range 2θ from 20 to 80°. The crystallite sizes were concluded from

XRD data using the Scherrer equation and α-Al2O3 was used as standard. The

instrument has been located at Center of Excellence on Catalysis and Catalytic

Reaction, Faculty of Science, Silpakorn University.

4.2.2 Temperature Programmed Reduction (TPR)

The temperature programmed reduction was used to determine bulk reduction

behavior and the reducibility of each catalyst. The hydrogen consumption was

measured by using a Micrometritics AutoChem II 2910 instrument. A 0.1 g of a

catalyst sample is placed in a quartz tubular reactor. Under nitrogen atmosphere at a

flow rate of 25 ml/min, the catalyst sample was heated up to 150°C and held 1 h in

order to eliminate the adsorbed water. After that, the system is cooled down to room

temperature. The reduction step is performed under 10% H2 in N2 flow of 25 ml/min

from room temperature to 800 °C at a heating rate of 10 °C/min.

26

4.3 Catalyst Activity

The catalytic activity was tested using hydrogen production from methanol.

The gases used in this test are listed in table 4.2. They were all supplied by Thai

industrial gas limited.

Table 4.2 The details of gases used in the catalyst activity test.

Gases Formula Grade

Argon Ar Ultra high purity

Hydrogen H2 High purity

A flow diagram of the system for testing the catalytic activity is showed in

Figure 4.2. An apparatus consisted of a saturated system, a fixed tubular reactor, an

automation temperature controller, an electrical furnace, a gas controlling system and

two sets of gas chromatography. The instruments used in this system were listed and

explained as follows:

27

Figure 4.2 Schematic diagram of the reaction and line for testing analyzed by GC-

TCD and GC-FID equipped with Porapak Q and DB-1 column,

respectively.

1. Saturated system: Liquid reactants, methanol and water, were loaded in

glass chamber set on plate which was controlled by temperature controller at 150 °C

2. Reactor: All reactions were tested using the conventional micro-reactor

made from stainless steel tube with 0.95 cm inside diameter. Catalyst sample was

placed between two quartz wool layers. The reaction was carried out under ordinary

gas flow and atmospheric pressure. The effluent gases were sampled and analyzed by

on-line gas chromatography.

3. Automation Temperature Controller: This unit consisted of a magnetic

switch connected to a variable voltage transformer and a solid state relay temperature

controller connected to a thermocouple. Reactor temperature was measured at the

bottom of the catalyst bed in the reactor. The set point of temperature control was

adjustable within the range of 0 to 800 °C at the maximum voltage output of 220 volt.

4. Electrical furnace: The furnace supplied the required heat to the reactor.

The reactor could be operated from room temperature up to 800 °C at the maximum

voltage of 220 volt.

28

5. Gas Controlling System: The flow rate of each gas used in this study was

controlled by a gas controlling system which consisted of pressure regulators and

metering valves.

6. Gas Chromatograph: The compositions of hydrocarbons in the product

stream were analyzed by two Shimadzu GC-14B gas chromatographs. One was

equipped with a thermal conductivity detector and another was equipped with a flame

ionization detector. The operating conditions for each instrument are shown in the

tables 3.3 and 3.4, respectively.

Table 4.3 The operating conditions of TCD gas chromatographs for the catalytic

activity test.

Gas chromatograph Shimadzu GC-14B

Detector TCD

Column Porapak Q

Carrier gas Ar (UHP)

Carrier gas flow 30 ml/min

Injector temperature 150 °C

Detector temperature 150 °C

Column temperature 40 °C (held 5 min) and then raised at 20 °C/min to

120 °C (held 10 min)

Analysis gas H2 ,CO, CO2, CH4, H2O and MeOH

29

Table 4.4 The operating conditions of FID gas chromatographs for the catalytic

activity test.

Gas chromatograph Shimadzu GC-14B

Detector FID

Column DB-1

Carrier gas N2 (UHP)

Split/Splitless Split (40 ml/min)

Purge flow rate 10 ml/min

Carrier pressure 40 kPa

Make up pressure 50 kPa

Injector temperature 200 °C

Detector temperature 200 °C

Column temperature 40 °C

Analysis gas MeOH, Hydrocarbons

30

4.3.1 Catalytic activity of hydrogen production from methanol

Catalytic activities of all samples for hydrogen production from methanol

were studied at a steady state in a fixed-bed reactor with an on-line GC. For each

experiment, 0.2 ml of the catalyst was packed in a fixed bed tubular reactor. Checking

feed containing the liquid methanol and water at furnace temperature is 100 C, a

heating rate of 10 C/min from room temperature then fed argon at a flow rate 50

ml/min through the saturator containing the liquid methanol and water. Prior to the

catalytic activity test, the catalyst was pretreated with argon at 350 C for 1 h and

reduced by hydrogen at 300 C for 1 h. After that, cool down by argon at 200 C. The

experiments were performed at atmospheric pressure, and range of temperature was

200-350 C which increased by 25 °C. The reactant feed was consisted of methanol

and water that was introduced into the reactor by argon and the product samples were

collected at 30 min in each temperature. The composition of the effluent was

measured by online gas chromatograph equipment, GC-TCD with Porapak Q column

and GC-FID with DB-1 column.

31

CHAPTER V

RESULTS AND DISCUSSION

The effect of cerium oxide on copper-alumina and copper-zinc oxide-alumina

catalyst prepared by flame spray pyrolysis which characterized and evaluated in

hydrogen production from methanol. The results and discussion in this chapter were

divided into two parts. In the first part, the catalytic properties and performances of

hydrogen production from methanol of Cu-Al2O3 which promoted with CeO2 using

percentages loading as 1, 3, 5 and 10 wt.%. The effect of CeO2 promoter on Cu-ZnO-

Al2O3 in FSP catalysts were various ZnO loading which evaluated in the second part.

5.1 The physical and chemical properties of CeO2 on Cu-Al2O3 catalysts

prepared by flame spray pyrolysis on hydrogen production from methanol.

In first part, the catalysts containing Cu on Al2O3 supported which various Cu

loading as 10-50 wt.% were studied. The appropriate percentage of copper was

selected to promoted with CeO2 using percentages loading as 1, 3, 5 and 10 wt.%. The

catalytic properties were characterized by various methods. The phase identification

and the average crystalline size were determined by the X-ray diffraction technique

(XRD). The temperature programmed reduction (TPR) exhibited reduction behavior

and reducibility of the catalysts.

32

5.1.1 The phase analysis by X-ray diffraction (XRD)

XRD patterns of the Cu-Al2O3 catalysts with different copper loading are

shown in Figure 5.1. The XRD pattern has shown the presence of CuO, -Al2O3 and

CuAl2O4 species. Patel and Pant [44] have concluded that the presence of alumina

enhances the dispersion of CuO species by the stabilization of isolated Cu2+ ions in

their matrix, and moderately by the formation of spinel like CuAl2O4. When increase

copper loading, the XRD peaks corresponding to CuO crystal phases were observed

and the intensity increased with the increasing copper loading and 50Cu-Al catalyst

showed the highest peak intensity, in agreement with the literature [45, 46].

Figure 5.1 XRD patterns of the Cu-Al2O3 catalysts.

Table 5.1 shows crystallite size of all species visible in the XRD spectra

calculated using the Sherrer equation. The crystallite size of CuO was also increased

by the addition of copper oxide, that is, the sizes were 2.4 nm for 10 wt.% CuO, 10.8

nm for 20 wt.% , 13.8 nm for 30 wt.%, 16.5 nm for 40 wt.% and 17.2 nm for 50 wt.%.

Moreover, the crystallite size of CuAl2O4 for 50Cu-Al catalyst was 13.7 nm while the

crystallite size of others catalysts about 5.4-7.4 nm.

33

Table 5.1 The crystalline size of Cu-Al2O3 catalysts.

5.1.2 Reductive behavior of copper oxides by TPR

Figure 5.2 TPR profiles of Cu-Al2O3 catalysts.

Catalysts

Crystalline size (nm)

CuO -Al2O3 CuAl2O4

10Cu-Al 2.4 30.5 7.4

20Cu-Al 10.8 25.0 5.9

30Cu-Al 13.8 27.3 5.4

40Cu-Al 16.5 29.5 6.0

50Cu-Al 17.2 23.2 13.7

34

The reduction properties of Cu-Al2O3 catalysts were investigated by H2–TPR

experiments and profiles are shown in Figure 5.2. The TPR profiles revealed the

reducibility of CuO in the Cu-Al2O3 catalysts which are shown in table 5.2. The TPR

profiles of all catalysts showed two reduction peaks, which included one lower

reduction temperature peak (the shoulder peak) and one higher reduction temperature

peak (the main peak). The two reduction peaks were due to the reduction of different

Cu species. These two copper species could be a highly dispersed copper phase

together with larger copper particles [47, 22]. Both peak area and peak intensity

increased significantly with increasing copper content and also the maximum peak

temperatures shifted to high temperature region with copper content, from 204 ºC for

10Cu-Al to 276 ºC for 50Cu-Al. This is in accordance with the results of

Gunawardana et al. [45] and Pérez-Hernandez et al. [48], who also observed that the

maximum peak temperatures shifted to high temperatures with increasing copper

content.

Table 5.2 The reducibility of Cu-Al2O3 catalysts.

5.1.3 The catalytic activity of Cu-Al2O3 catalysts prepared by

flame spray pyrolysis on hydrogen production from methanol.

Figure 5.3-5.6 shows the results of the methanol steam reforming over Cu-

Al2O3 prepared by flame spray pyrolysis. The catalyst activities, expressed as the

methanol conversion as a function of reaction temperature, is shown for the various

copper loading on Cu-Al2O3 catalysts in Figure 5.3. On all the samples, methanol

conversion starts above 200 ºC. The optimum Cu loading was 20% indicating the

highest methanol conversion and H2 production rate. On the other hand, the 50Cu-Al

catalyst had the lowest catalytic activity. The methanol conversion was only 9.8% at

Catalysts 10Cu-Al 20Cu-Al 30Cu-Al 40Cu-Al 50Cu-Al

% Reducibility 79.9 81.4 85.9 86.3 84.4

35

350 ºC. For these catalysts the excessive loading of copper did not perform well

which might be due to formation of larger copper crystallites that resulted in low

surface area or due to formation of larger CuAl2O4.

Figure 5.3 MeOH conversion on Cu-Al2O3 catalysts in range 200-350 °C.

Figure 5.4 H2 production rate on Cu-Al2O3 catalysts in range 200-350 °C.

36

Figure 5.5 The H2/CO2 ratio on Cu-Al2O3 catalysts in range 275-350 °C.

Over all the tested Cu-Al2O3 catalysts, HC and CH4 were detected as a by-

product. H2/CO2 ratio was obtained 2.6-2.7 (Figure 5.5) for 20Cu-Al which

theoretical results H2/CO2 was 3. These results reveal that unfavorable reactions such

as CO hydrogenation have influence on the performance of the methanol steam

reforming. When copper loading was increased, the quantity of the by-products

detected increased. Thus, the by-product formation is also directly related to the

copper loading in the catalysts.

The route of CO and CO2 formation was investigated in our experiments

(Figure 5.6). If the mechanism of the methanol decomposition (DM) followed by

water gas shift reaction (WGS) was assumed, CO should be firstly formed by DM,

subsequently converted into CO2 in the WGS reaction. According to the mechanism,

the CO formation of all catalysts indicated that the catalysts favored methanol

decomposition at low temperature consistent with the formation of quantities of CO2

is observed only above 275 ºC for 10Cu-Al and 20Cu-Al. The CO2 production over

only 10Cu-Al and 20Cu-Al catalysts indicated the different catalytic behavior of low

and high Cu loading. For high Cu loading, an amount of CH4 was detected over

catalysts decreased while increasing the copper content.

37

CH3OH 2H2 + CO (DM)

CO + H2O H2 + CO2 (WGS)

CO + 3H2 CH4 + H2O (CO hydrogenation)

38

Figure 5.6 Pathway of reaction on Cu-Al2O3 catalysts in range 200-350 °C.

39

Thus, we have studied the effect of CeO2 promoter on 20Cu-Al catalyst by

various percentages of CeO2 loading as 1, 3, 5 and 10 wt.% to improve the catalytic

properties and performances of hydrogen production from methanol of 20Cu-Al

catalyst.


Figure 5.7 XRD patterns of the Cu-CeO2-Al2O3 catalysts.

Figure 5.7 displays the XRD patterns of the Cu-CeO2-Al2O3 catalysts with

different cerium loadings. The Cu-CeO2-Al2O3 has shown the presence CuO, -Al2O3

and CuAl2O4 species in all the spectra obtained from the catalyst samples. Peaks at

35.5º, 38.8º, and 48.7º in 2θ attributed to CuO were recorded with peaks attributed to

-Al2O3 in the XRD pattern for Cu-CeO2-Al2O3 [2]. Moreover, it can be seen CeO2 is

observed in samples which the characteristic peaks of CeO2 was at 2θ = 28.4º. But at

low cerium loadings (1 and 3 wt.%), no peaks due to CeO2 can be detected in the

XRD spectrum. Lack of CeO2 peaks at low cerium loading suggests that CeO2

particles are too small to be detected by XRD or due to the low crystallinity and the

lower cerium concentration. When cerium loading increased, the XRD peaks

40

corresponding to CeO2 crystal phases were observed and the intensity increased with

the increasing cerium loading.

Table 5.3 The crystalline size of Cu-CeO2-Al2O3 catalysts.

Table 5.3 displays the crystalline size of Cu-CeO2-Al2O3 catalysts. When low

CeO2 loading was added to Cu-Al2O3, the diffraction patterns of CuO weakened and

widened, indicating that the crystallite size of CuO decreased and the dispersion of

CuO was improved in the catalysts. The mean crystallite size of CuO was calculated

to about 5.5-13.0 nm from the peak at 48.7 using Scherrer equation.


Temperature programmed reduction (TPR) was performed in order to

determine the reduction behaviors. The effect of cerium loading on the catalyst

reducibility was also verified and discussed. Figure 5.8 shows the TPR profiles of Cu-

CeO2-Al2O3 catalysts at different cerium loading. It is evident that all CeO2-

containing catalysts are reduced at higher temperatures compared to Cu-Al2O3

catalyst. This is surprising, since addition of CeO2 usually results in catalysts that are

Catalysts


CuO -Al2O3 CuAl2O4 CeO2

20Cu-Al 10.8 25.0 5.9 -

20Cu-1Ce-Al 9.6 25.0 6.1 n.d.

20Cu-3Ce-Al 5.5 24.1 7.0 n.d.

20Cu-5Ce-Al 8.0 52.1 6.6 16.1

20Cu-10Ce-Al 13.0 28.3 8.0 17.6

41

easy to reduce [3]. Both peak area and peak intensity decreased with increasing

cerium loading and also the maximum peak temperatures shifted to high temperature

region with cerium loading. Furthermore, Breen and Ross indicated that catalysts

which reduce at lower temperatures were more active methanol steam reforming

catalysts [47]. But the catalysts in this study do not follow this trend. In fact, the most

active catalyst, 20Cu-3Ce-Al, exhibits higher reduction temperature. Therefore, under

these conditions there is no correlation between the methanol conversion and the

reduction temperature for this series of catalysts. In agreement with literatures which

indicate that the reducibility of the copper species does not play the role in catalytic

performance, and in some cases the catalysts which are more difficult to reduce tend

to be more active [3,49].

Figure 5.8 TPR profiles of Cu-CeO2-Al2O3 catalysts.

The profile of the Cu-CeO2-Al2O3 catalysts was the different as that of the Cu-

Al2O3. Cu-CeO2-Al2O3 were only one reduction peak at around 255 ºC, which was

considerably higher than the reduction temperature reported for Cu-Al2O3 shown at

42

around 217 ºC. For the Cu-Al2O3 catalyst, the TPR profiles of the catalysts showed

two reduction peaks, which included one lower reduction temperature peak (the

shoulder peak) and one higher reduction temperature peak (the main peak). The two

reduction peaks were due to the reduction of different Cu species. The shoulder peak

is attributed to reduction of highly dispersed CuO species, the main peak is attributed

to the reduction of bulk CuO species [50].

Table 5.4 The reducibility of Cu-CeO2-Al2O3 catalysts.

5.1.6 The catalytic activity of CeO2 on Cu-Al2O3 catalysts prepared

by flame spray pyrolysis on hydrogen production from methanol.

Figures 5.9 show methanol conversion as a function of temperature on Cu-

CeO2-Al2O3 with various cerium loadings in range 200-350 °C. The methanol

conversion increased slightly with temperature increased. The 20Cu-3Ce-Al catalyst

exhibits the best performance of all catalysts in this series. Only at the highest

temperature (350 ºC) does the 20Cu-5Ce-Al catalyst have a slightly higher conversion

than the 20Cu-3Ce-Al catalyst. The 20Cu-10Ce-Al catalyst exhibits the poorest

performance of these catalysts with a maximum methanol conversion of 46%.

Addition CeO2 into Cu-Al2O3 slightly promoted the MSR reaction. The methanol

conversion increased compared to the Cu-Al2O3 catalyst at each reaction temperature.

It implied that the CeO2 was a suitable promoter for MSR reaction. However, the

excessive loading of CeO2 was leading to the lower activity which the H2 production

rate (Figure 5.10) seemed to have the same trends as the methanol conversion.

Catalysts 20Cu-Al 20Cu-1Ce-Al 20Cu-3Ce-Al 20Cu-5Ce-Al 20Cu-10Ce-Al

% Reducibility 81.4 90.4 90.7 91.4 93.3

43

Figure 5.9 MeOH conversion on Cu-CeO2-Al2O3 catalysts in range 200-350 °C.

Figure 5.10 H2 production rate on Cu-CeO2-Al2O3 catalysts in range 200-350 °C.

44

Figure 5.11 The H2/CO2 ratio on Cu-CeO2-Al2O3 catalysts in range 275-350 °C.

H2/CO2 ratio was obtained 3 (Figure 5.11) for 20Cu-3Ce-Al and 20Cu-5Ce-Al

catalysts which values were rather consistent with the stoichiometry of the MSR

reaction. Moreover, the roles of CeO2 loading were clearly observed in decreasing CO

formation and increasing H2 selectivity in the range of reaction temperatures. At high

temperature, amount of CH4 were detected and disappears while increasing the cerium

content.

The route of CO and CO2 formation was investigated in our experiments.

Initially, the mechanism of the methanol decomposition (DM) followed by water gas

shift reaction (WGS) [51] has been assumed. Some early studies proposed that the

steam reforming of methanol consists in the sequence of the methanol decomposition

followed by WGS equilibrium, being CO the primary product that is easily converted

into CO2 [52,53]. According to the mechanism, the CO formation of 20Cu-Al and

20Cu-10Ce-Al indicated that the catalysts favored methanol decomposition at low

temperature consistent with no CO2 formation in the product gas at low temperature.

CH3OH 2H2 + CO (DM)


45

Moreover, addition of CeO2 as 1, 3 and 5 wt.% into the 20Cu-Al catalyst

promoted activity of catalyst and the CO formation significantly decreased. The

phenomena were mainly due to the fact that CeO2 had the function of oxygen storage

capacity which was confirmed by Fernandez-Garcia [54]. Catalysts modified by CeO2

showed significant enhancement not only in terms of methanol conversion but also in

terms of H2 production rate and minimization of CO formation. Thus, it is the suitable

promoter for the MSR.

46

Figure 5.12 Pathway of reaction on Cu-CeO2-Al2O3 catalysts in range 200-350 °C.

47

5.2 The physical and chemical properties of CeO2 on Cu-ZnO-Al2O3

catalysts prepared by flame spray pyrolysis on hydrogen production from

methanol.

In second part, we have studied the effect of CeO2 promoter on Cu-ZnO-Al2O3

catalysts by percentages of CeO2 loading as 3 wt.% because the 20Cu-3Ce-Al catalyst

exhibits the best performance of all catalysts in first part. Thus, in this part,

percentages of ZnO loading were various as 1, 3, and 10 wt.% to improve the

catalysts. The catalytic properties were characterized by various methods. The phase

identification and the average crystalline size were determined by the X-ray

diffraction technique (XRD). The temperature programmed reduction (TPR) exhibited

reduction behavior and reducibility of the catalysts.


Figure 5.13 XRD patterns of the Cu-ZnO-Al2O3 catalysts.

Figure 5.13 shows the XRD spectra of the Cu-ZnO-Al2O3 catalysts at different

ZnO loading. There are peaks in the spectrum which corresponded to the CuO phase

48

and a crystalline ZnO phase is present on the 20Cu-3Zn-Al and 20Cu-10Zn-Al

catalysts but not on the 20Cu-1Zn-Al catalyst. On the 20Cu-1Zn-Al the ZnO is below

the detection limit or is present in amorphous form. Meanwhile, the diffraction peaks

of CuO and ZnO evidently overlapped, and the part of ZnO diffraction peaks

disappeared. It indicated that the interaction between CuO and ZnO was strengthened.

There are peaks visible in the spectrum of all catalysts at 2Ɵ = 31.3º, 37.1º, 44.6º,

55.6º, 59.2º, and 65.1º which are not due to CuO or ZnO. The 2Ɵ values of the peaks

are consistent with those obtain from aluminate species such as CuAl2O4 or ZnAl2O4.

Since both the CuAl2O4 and ZnAl2O4 have nearly identical diffraction patterns is it

difficult to distinguish between the two in the XRD spectrum obtained from the

catalysts [7]. In first part, Cu-Al2O3 catalysts were characterized with XRD

measurements. We found that the presence of an aluminate phase was visible with

XRD in the Cu-Al2O3 catalysts. This result suggests that the aluminate phase seen in

the XRD spectra obtained from the all catalysts in this part is CuAl2O4 and not

ZnAl2O4.

Table 5.5 The crystalline size of Cu-ZnO-Al2O3 catalysts.



by the addition of zinc oxide, that is, the sizes were 7.2 nm for 1 wt.% ZnO, 8.0 nm

Catalysts


CuO -Al2O3 CuAl2O4 ZnO

20Cu-Al 10.8 25.0 5.9 -

20Cu-1Zn-Al 7.2 27.1 5.9 n.d.

20Cu-3Zn-Al 8.0 25.5 5.4 n.d.

20Cu-10Zn-Al 11.3 19.7 8.5 n.d.

49

for 3 wt.% and 11.3 nm for 10 wt.%. On the other hand, the crystallite size of -Al2O3

decreased. Moreover, the crystallite size of CuAl2O4 for 20Cu-10Zn-Al catalyst was

8.5 nm while the crystallite size of others catalysts about 5.4-5.9 nm.


Figure 5.14 TPR profiles of Cu-ZnO-Al2O3 catalysts.

The TPR profiles (Figure 5.14) revealed the reducibility of CuO in the Cu-

ZnO-Al2O3 catalysts. For all the catalysts investigated, reduction began at around 150

ºC and completed at 260 ºC. The profile of the Cu-ZnO-Al2O3 catalyst was the same

as that of the Cu-Al2O3. There were two overlapped reduction peaks, which included

one lower reduction temperature peak (the shoulder peak) and one higher reduction

temperature peak (the main peak). The presence of two peaks in the samples is an

indication of the existence of more than one copper species in the catalysts. Except for

the 20Cu-10Zn-Al catalyst, the TPR profiles of the catalyst showed only one

reduction peak at around 232 ºC. The temperature of the main peak shifted from 217

to 232 ºC as 10% ZnO was introduced into Cu-Al2O3. These temperatures are

50

considerably lower than the reduction temperature reported for pure CuO, which

showed a single large peak at around 340 ºC [44, 55, 56]. Addition of ZnO, no

reduction peak assigned to ZnO species was shown in the spectra. While adding zinc

oxide, the reducibility of CuO was higher about 93-97% as shown in table 5.6.

Compared to the 20Cu-Al, ZnO incorporation by FSP enhances the reducibility of

copper.

Table 5.6 The reducibility of Cu-ZnO-Al2O3 catalysts.

5.2.3 The catalytic activity of Cu-ZnO-Al2O3 catalysts prepared by

flame spray pyrolysis on hydrogen production from methanol.

All the catalysts were tested for the production of hydrogen via methanol

steam reforming. The main products of the MSR reaction were H2, CO2 and CO.

Moreover, by-products of MSR containing CH4 and HC which HC detected in small

amounts. Methanol conversion as a function of temperature for each catalyst tested is

shown in Figure 5.15. Moreover, for all the catalysts, the activity increased

monotonically with the temperature because of the endothermic property of MSR.

The 20Cu-10Zn-Al catalyst had the highest catalytic activity. The methanol

conversion was 72% at 350 ºC. Adding the ZnO promoter, the catalyst activity was

further improved. The methanol conversion increased compared to the 20Cu-Al

catalyst at each reaction temperature. It implied that the ZnO was a suitable promoter

for MSR reaction. Catalysts modified by ZnO showed significant enhancement not

only in terms of methanol conversion but also in terms of H2 production rate. For the

H2 production rate (Figure 5.16) seemed to have the same trends as the methanol

conversion.

Catalysts 20Cu-Al 20Cu-1Zn-Al 20Cu-3Zn-Al 20Cu-10Zn-Al

% Reducibility 81.4 94.9 93.3 96.6

51

Figure 5.15 MeOH conversion on Cu-ZnO-Al2O3 catalysts in range 200-350 °C.

Figure 5.16 H2 production rate on Cu-ZnO-Al2O3 catalysts in range 200-350 °C.

Figure 5.17 showed the H2/CO2 ratio as a function of reaction temperature.

The H2/CO2 ratio was below the value than obtained from stoichiometry of the MSR

52

reaction, indicating that the reaction pathway of methanol steam reforming go through

CO hydrogenation. The CH4 molar concentration increased along with the

temperature. This was because that CH4 as the by-product was mainly produced by

the CO hydrogenation reaction

Figure 5.17 The H2/CO2 ratio on Cu-ZnO-Al2O3 catalysts in range 275-350 °C.

As shown in Figure 5.18, for 20Cu-Al and 20Cu-1Zn-Al catalysts CO

formation can be observed at low temperature. It is implied that methanol decompose

to form the CO and then CO converts to CO2 and CH4 at high temperature (275 ºC).

On the other hand, other researchers report on a direct mechanism for the MSR

process, where CO2 and H2 are formed form methanol in a single step [57-60]. For

instance, Geissler et al. [60] studied commercial Cu/ZnO/Al2O3 catalysts and from

measurements showing lower CO concentrations than determined by equilibrium

calculations they concluded that the SRM reaction is a single-step process, i.e. not a

consecutive reaction consisting of methanol decomposition followed by WGS.

According to the result of 20Cu-3Zn-Al and 20Cu-10Zn-Al catalysts, the CO2 was

formed previously. The results showed that the methanol steam reforming was a

single-step process.

53

Figure 5.18 Pathway of reaction on Cu-ZnO-Al2O3 catalysts in range 200-350 °C.

54

Thus, we have studied the effect of CeO2 promoter on Cu-ZnO-Al2O3 catalysts

by fixed percentages of CeO2 loading as 3 wt.% and various percentages of ZnO

loading as 1, 3, and 10 wt.% to improve the catalysts.


Figure 5.19 XRD patterns of the Cu-ZnO-CeO2-Al2O3 catalysts.

XRD spectra obtained from the catalysts are shown in Figure 5.19 which

shown Cu-ZnO-CeO2-Al2O3 catalysts with different zinc oxide loading. Peaks at

35.5º, 38.8º, and 48.7º in 2θ attributed to CuO were recorded with peaks attributed to

-Al2O3 in the XRD pattern for Cu-ZnO-CeO2-Al2O3 [2]. Moreover, it can be seen

CeO2 is observed in samples which the characteristic peaks of CeO2 was at 2θ = 28.4º.

The characteristic peaks of CuO, -Al2O3, CuAl2O4 and CeO2 are evident in all the

spectra obtained from the catalyst samples but no crystalline ZnO phase is present on

the catalysts, implying that ZnO phase are probably present micro-crystallite state in

catalysts.

55

Table 5.7 The crystalline size of Cu-CeO2-Al2O3, Cu-ZnO-Al2O3 and Cu-ZnO-

CeO2-Al2O3 catalysts.

Table 5.7 shows crystalline size of all species visible in the XRD spectra

calculated using the Sherrer equation. The sizes of the CuO particles are slightly

smaller on Cu-ZnO-Al2O3 catalyst compared with Cu-ZnO-CeO2-Al2O3 catalysts.

Another interesting observation is that the particle sizes of the aluminate species of

Cu-ZnO-CeO2-Al2O3 catalysts are smaller than for the CuO species. The Sherrer

equation gives a value about 5-10 nm for the aluminate. The small particle size

observed is likely due to the strong metal-support interactions that result in formation

of this compound. Addition of cerium oxide to Cu-ZnO-Al2O3 increased the

crystalline size of CuO to 13–14 nm. XRD results showed that CeO2 had a significant

influence on surface copper dispersion and crystallite sizes.

Catalysts


CuO -Al2O3 CuAl2O4 CeO2

20Cu-1Zn-Al 7.2 27.1 5.9 n.d.

20Cu-3Zn-Al 8.0 25.5 5.4 n.d.

20Cu-10Zn-Al 11.3 19.7 8.5 n.d.

20Cu-3Ce-Al 5.5 24.1 7.0 n.d.

20Cu-1Zn-3Ce-Al 13.4 49.8 10.0 14.6

20Cu-3Zn-3Ce-Al 12.9 24.1 4.9 7.2

20Cu-10Zn-3Ce-Al 14.1 32.6 5.2 13.5

56


Figure 5.20 TPR profiles of Cu-ZnO-CeO2-Al2O3 catalysts.

The reduction properties of Cu-ZnO-CeO2-Al2O3 catalysts were investigated

by H2–TPR experiments and profiles are shown in Figure 5.20. For all the catalysts

investigated, reduction began at around 170-180 ºC and completed at 260-290 ºC. The

temperature of the main peak shifted from 252 to 235 ºC as 1% ZnO was introduced

into Cu-CeO2-Al2O3. Addition of ZnO, no reduction peak assigned to ZnO species

was shown in the spectra. All ZnO-containing catalysts exhibit two reduction peaks.

While it is possible that the two reduction peaks are due to a step-wise reduction of

CuO via Cu2O to Cu metal [61], another explanation is that the two peaks are due to

different types of Cu on the surface [23]. These two copper species could be a highly

dispersed copper phase together with larger copper particles [22, 47]. Moreover, it is

evident that all ZnO-containing catalysts are reduced at lower temperatures compared

to Cu-CeO2-Al2O3 catalyst. Clearly, the presence of ZnO could enhance reducibility

of the catalysts by shifting reduction peaks toward a lower temperature.

57

Table 5.8 The reducibility of Cu-ZnO-CeO2-Al2O3 catalysts.

Catalysts % Reducibility

20Cu-3Ce-Al 90.7

20Cu-1Zn-3Ce-Al 97.4

20Cu-3Zn-3Ce-Al 96.6

20Cu-10Zn-3Ce-Al 96.6

5.2.6 The catalytic activity of CeO2 on Cu-ZnO-Al2O3 catalysts

prepared by flame spray pyrolysis on hydrogen production from methanol.

The performances of the catalysts for the hydrogen production from methanol

are shown in Figure 5.21-5.26 which presents the catalytic activities of CeO2 on Cu-

ZnO-Al2O3 catalysts as a function of temperature. The ceria-promoted catalyst with

10 wt.% zinc oxide loading had the highest activity for the methanol steam reforming

reaction of all of the ceria-containing catalysts. Addition 3% of CeO2 over 20Cu-

10Zn-Al, the catalyst behavior becomes similar to 20Cu-10Zn-Al without any CO

formation. For ZnO loading as 3 wt.%, the initial activity (200-275 ºC) of 20Cu-3Zn-

Al was similar to that of 20Cu-3Zn-3Ce-Al, but the methanol conversion of 20Cu-

3Zn-Al was rapidly increased to 70% at 350 ºC. At low ZnO loading (1 wt.%), the

presence of CeO2 showed high catalytic activities in the reaction temperatures studied.

Interestingly, Cu-ZnO-CeO2-Al2O3 catalysts demonstrated much better catalytic

performance than those of the catalyst without CeO2 loading, indicating that the

presence of the CeO2 was necessary to efficiently promote catalytic activity. For the

H2 production rate seemed to have the same trends as the methanol conversion.

58

Figure 5.21 MeOH conversion of Cu-ZnO-Al2O3 (thin line) and Cu-ZnO-CeO2-

Al2O3 (dash line) catalysts at ZnO as 1 wt.% in range 200-350 °C.

Figure 5.22 H2 production rate of of Cu-ZnO-Al2O3 (thin line) and Cu-ZnO-CeO2-


59



Figure 5.24 H2 production rate of Cu-ZnO-Al2O3 (thin line) and Cu-ZnO-CeO2-


60



Figure 5.26 H2 production rate of Cu-ZnO-Al2O3 (thin line) and Cu-ZnO-CeO2-


61

Figure 5.27 The H2/CO2 ratio on Cu-ZnO-CeO2-Al2O3 catalysts in range 275-350

°C.

Figure 5.27 showed the H2/CO2 ratio as a function of reaction temperature.

H2/CO2 ratio was obtained 2.8-3 (Figure 5.27) for all catalysts which below the value

than obtained from stoichiometry of the MSR reaction, indicating that the reaction

pathway of methanol steam reforming go through CO hydrogenation. Moreover, the

roles of CeO2 loading were clearly observed in decreasing CO formation. At high

temperature, amount of CH4 were detected. The CH4 molar concentration increased

along with the temperature. This was because that CH4 as the by-product was mainly

produced by the CO hydrogenation reaction

As shown in Figure 5.28, other researchers report on a direct mechanism for

the MSR process, where CO2 and H2 are formed form methanol in a single step [57-

60]. According to the result of all catalysts in this part, the CO2 was formed

previously and no CO formation. The results showed that the methanol steam

reforming was a single-step process.

62

Figure 5.28 Pathway of reaction on Cu-ZnO-CeO2-Al2O3 catalysts in range 200-

350 °C.

63

Although Cu-ZnO-CeO2-Al2O3 catalysts can promote methanol steam

reforming but Cu-CeO2-Al2O3 demonstrated much better catalytic performance than

those of the catalysts. Thus, we studied the effect of preparation method to improve

performances of Cu-ZnO-Al2O3 modified by CeO2.


Figure 5.29 XRD patterns of the ZnO/Cu-CeO2-Al2O3 catalysts.

XRD patterns of the ZnO/Cu-CeO2-Al2O3 catalysts with different zinc loading

are shown in Figure 5.29. The XRD pattern has shown the presence of CuO, -Al2O3,

CuAl2O4, ZnO and CeO2 species. Peaks at 35.5º, 38.8º, and 48.7º in 2θ attributed to

CuO were recorded with peaks attributed to -Al2O3 in the XRD pattern for Cu-CeO2-

Al2O3 [2]. Moreover, it can be seen CeO2 is observed in samples which the

characteristic peaks of CeO2 was at 2θ = 28.4º. When increase zinc loading, the XRD

peaks corresponding to ZnO crystal phases were observed and the intensity increased

with the increasing zinc loading and 10Zn/20Cu-3Ce-Al catalyst showed the highest

peak intensity.

64

Table 5.9 The crystalline size of ZnO/Cu-CeO2-Al2O3 catalysts.



by the addition of zinc oxide, that is, the sizes were 11 nm for 1 wt.% ZnO, 21 nm for

3 wt.% but decreased for 10 wt.% ZnO, i.e. 17.2 nm. Moreover, the crystallite size of

CuAl2O4 for 10Zn/20Cu-3Ce-Al catalyst was 13.7 nm while the crystallite size of

others catalysts about 6-7 nm.


The reduction properties of ZnO/Cu-CeO2-Al2O3 catalysts were investigated

by H2–TPR experiments and profiles are shown in Figure 5.30. For all the catalysts

investigated, reduction began at around 200 ºC and completed at 330 ºC. The profile

of the ZnO/Cu-CeO2-Al2O3 catalyst was the same as that of the Cu-CeO2-Al2O3

which have only one reduction peak. Figure 5.30 shows the TPR profiles of ZnO/Cu-

CeO2-Al2O3 catalysts at different zinc loading. It is evident that all ZnO-containing

catalysts are reduced at higher temperatures compared to Cu-CeO2-Al2O3 catalyst.

This is surprising, since addition of ZnO usually results in catalysts that are easy to

reduce. The temperature of the peak shifted from 252 to 297 ºC as 10% ZnO was

introduced into 20Cu-3Ce-Al.

Catalysts


CuO -Al2O3 CuAl2O4 CeO2 ZnO

20Cu-3Ce-Al 5.5 24.1 7.0 n.d. -

1Zn/20Cu-3Ce-Al 11.0 37.1 6.0 10.3 10.5

3Zn/20Cu-3Ce-Al 21.0 29.7 6.1 13.3 12.8

10Zn/20Cu-3Ce-Al 17.2 75.6 13.7 4.1 71.5

65

Figure 5.30 TPR profiles of ZnO/Cu-CeO2-Al2O3 catalysts.

Addition of ZnO, no reduction peak assigned to ZnO species was shown in the

spectra. While adding zinc oxide, the reducibility of CuO was higher about 91-93% as

shown in table 5.10.

Table 5.10 The reducibility of ZnO/Cu-CeO2-Al2O3 catalysts.

Catalysts % Reducibility

20Cu-3Ce-Al 90.7

1Zn/20Cu-3Ce-Al 92.6

3Zn/20Cu-3Ce-Al 91.1

10Zn/20Cu-3Ce-Al 91.0

66

5.2.9 The catalytic activity of ZnO impregnated on Cu-CeO2-Al2O3

catalysts prepared by flame spray pyrolysis on hydrogen production from

methanol.

Figure 5.31-5.32 shows the results of the methanol steam reforming of over

ZnO/Cu-CeO2-Al2O3 which impregnated ZnO on Cu-CeO2-Al2O3 prepared by flame

spray pyrolysis. The main products of the MSR reaction were H2, CO2 and CO.

Moreover, by-products of MSR containing CH4 and HC which HC detected in small

amounts. The catalyst activities, expressed as the methanol conversion as a function

of reaction temperature, is shown for the various zinc loading on Cu-CeO2-Al2O3

catalysts. On all the samples, methanol conversion starts above 200 ºC. At low

temperature, methanol conversion increased slightly with temperature increased. On

the other hand, methanol conversion increased rapidly at high temperature. The

1Zn/20Cu-3Ce-Al catalyst exhibits the best performance of all catalysts in this series.

The methanol conversion was 77% at 350 ºC. For the H2 production rate (Figure 5.22)

seemed to have the same trends as the methanol conversion.

Figure 5.33-5.34 shows methanol conversion and H2 production rate of Cu-

ZnO-CeO2-Al2O3 compared with ZnO/Cu-CeO2-Al2O3. Interestingly, Cu-ZnO-CeO2-

Al2O3 catalysts demonstrated much better catalytic performance than ZnO/Cu-CeO2-

Al2O3 especially at low temperature, indicating that ZnO incorporated by FSP

necessary to efficiently promote catalytic activity in all reaction temperature more

than ZnO impregnated.

67

Figure 5.31 MeOH conversion on ZnO/Cu-CeO2-Al2O3 catalysts in range 200-350

°C.

Figure 5.32 H2 production rate on ZnO/Cu-CeO2-Al2O3 catalysts in range 200-350

°C.

68

Figure 5.33 MeOH conversion on Cu-ZnO-CeO2-Al2O3 (thin line) and ZnO/Cu-

CeO2-Al2O3 (dash line) catalysts in range 200-350 °C.

Figure 5.34 H2 production rate on Cu-ZnO-CeO2-Al2O3 (thin line) and ZnO/Cu-

CeO2-Al2O3 (dash line) catalysts in range 200-350 °C.

69

Figure 5.35 The H2/CO2 ratio on ZnO/Cu-CeO2-Al2O3 catalysts in range 275-350

°C.

Over all the tested ZnO/Cu-CeO2-Al2O3 catalysts, HC and CH4 were detected

as a by-product. H2/CO2 ratio was obtained 2.7-2.9 (Figure 5.35) which theoretical

results H2/CO2 was 3. At high temperature, amount of CH4 were detected and

disappears while increasing the zinc loading.

The route of CO and CO2 formation was investigated in our experiments. The

decomposition-WGS sequence has been proposed by some authors [51-53]. In this

scheme, CO is believed to be a primary product, subsequently converted into CO2 in

the WGS reaction. According to the mechanism, the CO formation of all catalysts

indicated that the catalysts favored methanol decomposition at low temperature

consistent with the formation of quantities of CO2 is observed only above 275 ºC for

all catalysts.

CH3OH 2H2 + CO (DM)


70

Figure 5.36 Pathway of reaction on ZnO/Cu-CeO2-Al2O3 catalysts in range 200-

350 °C.

71

CHAPTER VI

CONCLUSIONS

In this research, the conclusions of these results were as follows:

1. Addition of CeO2 as 1, 3 and 5 wt.% into the Cu-Al2O3 catalyst promoted

activity of catalyst

2. At low ZnO loading (1 wt.%), Cu-ZnO-CeO2-Al2O3 catalysts demonstrated

much better catalytic performance than the catalyst without CeO2 loading.

3. For ZnO impregnated on Cu-CeO2-Al2O3 catalysts, the methanol

decomposition can be promoted more than the methanol steam reforming.

72

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APPENDIX A

APPENDIX B

APPENDIX C

APPENDIX D

APPENDIX E

APPENDICES

80

APPENDIX A

CALCULATION OF CATALYST PREPARATION

Calculation of catalyst prepared by flame spray pyrolysis

Table A.1 Properties of precursor

Metal

MW of metal

(g)

Metal precursor

MW of metal precursor

(g)

Purity

(%)

Cu 63.546 Cu(NO3)2·2.5H2O 232.59 99.0

CeO2 172.114 CeN3O9·6H2O 434.22 99.0

Al2O3 101.96 Al(NO3)3·9H2O 375.13 98.0

81

Preparation precursor Cu-CeO2-Al2O3 (FSP)

20Cu-1CeO2-Al2O3

Basis 100 g catalyst (Cu = 20 g, CeO2 = 1 g, Al2O3 = 79 g)

Mole Cu = 3147.0546.63

20 mol

Mole CeO2 = 0058.0114.172

1 mol

Mole Al2O3 = 7748.096.101

79 mol

Al = (2×0.7748) = 1.5496 mol

Total mole = 0.3147+0.0058+1.5496 = 1.8701 mol

XCu = 0.1683 XCeO2 = 0.0031 XAl2O3 = 0.8286

Precursor 500 cm3 concentration 0.5M

Total mole = 25.01000

5005.0 mol

Mole Cu = 0.0421 mol

Mole CeO2 = 0.0008 mol

Mole Al2O3 = 0.2072 mol

Cu(NO3)2·2.5H2O = 0.0421 × 232.59 ×99.01 = 9.8909 g

CeN3O9·6H2O = 0.0008 × 434.22 × 99.0

1 = 0.3509 g

Al(NO3)2·9H2O = 0.2072×375.13×98.01 79.3132 g

82

Wet-impregnation (CeO2/Cu-Al2O3)

Basis : Cu-Al2O3 2 g

Cu(NO3)2·2.5H2O

99.01

122.434

11

114.1721

973

2932

932.

93

2

2

OmolCeNg

molCeOOmolCeN

gmolCeO

gg

g OCeN

CeOcat

CeOcat

= 0.1576 g

83

APPENDIX B

CALCULATION OF THE CRYSTALLITE SIZE

Calculation of the crystallite size by Debye-Scherrer equation

The crystallite size was calculated from the half-height width of the diffraction

peak of XRD pattern using the Debye-Scherrer equation.

Figure B.1 Derivation of Bragg's Law for X-ray diffraction

sindyzxy

Thus sind2xyz

But nxyz

Therefore nsind2 Bragg’s

Law

84

sin2nd

The Bragg's Law was derived to C.1

From Scherrer equation:

cos KD

(C.1)

Where D = Crystallite size, Å

K = Crystallite-shape factor = 0.9

λ = X-ray wavelength, 1.5418 Å for CuKα

θ = Observed peak angle, degree

β = X-ray diffraction broadening, radian

The X-ray diffraction broadening (β) is the pure width of powder diffraction

free from all broadening due to the experimental equipment. α-Alumina is used as a

standard sample to observe the instrumental broadening since its crystallite size is

larger than 2000 Å. The X-ray diffraction broadening (β) can be obtained by using

Warren’s formula.

From Warren’s formula:

2S

2M BB

(C.2)

Where BM = The measured peak width in radians at half peak height.

BS = The corresponding width of the standard material.

85

Example: Calculation of the crystallite size of alumina

The half-height width of 111 diffraction peak = 1.83° (from Figure C.1)

= (π 1.83)/180

= 0.0319 radian

The corresponding half-height width of peak of α-alumina (from the Bs value

at the 2θ of 30.3° in Figure C.2) = 0.0036 radian

The peak width, 2S

2M BB

22 0036.00319.0

radian0317.0

Where B = 0.0317 radian

2θ = 30.3°

θ = 15.15°

λ = 1.5418 Å

The crystallite size = 15.15cos0317.0

5418.19.0 = 45.32 Å

= 4.5 nm

86

Figure B.2 The 111 diffraction peak of alumina for calculation of the crystallite

size

Figure B.3 The plot indicating the value of line broadening due to the equipment.

The data were obtained by using α-alumina as a standard.

87

APPENDIX C

CALCULATION FOR REDUCIBILITY

For supported copper catalyst, it can be assumed that the major species of

calcined Cu catalysts is CuO. H2 consumption to reduce CuO is calculated as follows:

Molecular weight of Cu = 63.546

Molecular weight of CuO = 79.545

Calculation of the calibration of H2 consumption using copper oxide (CuO)

Let the weight of CuO = 0.1 g

= 1.257x10-3 mole

From equation of CuO reduction;

CuO + H2 → Cu + H2O (E.1)

Mole of H2 consumption = Mole of CuO consumption

= 1.257x10-3 mole

Integral area of hydrogen used to reduce CuO 0.1 g = 8.7017 unit

At 100% reducibility, the amount of hydrogen consumption is 1.257x10-3

mole related to the integral area of CuO after reduction 8.7017 unit

Calculation of reducibility of supported copper catalyst

% Reducibility = Amount of H2 uptake to reduce 0.1 g of catalyst x100

Amount of theoretical H2 uptake to reduce CuO to Cu for 0.1 g of catalyst

88

Integral area of the calcined catalyst = X unit

The amount of H2 consumption = [1.257x10-3x (X)/ 8.7017] mole

Let the weight of calcined catalyst used = W g

Concentration of Cu = Y %wt

Amount of theoretical = /63.546Y/100W mole

% Reducibility = )100(/63.546Y/100W

8.7017](X)/ x [1.257x10 -3

Example for 10Cu-Al2O3

Integral area of the calcined catalyst = 0.8777 unit

The amount of H2 consumption = [1.257x10-3x (X)/ 8.7017] mole

Let the weight of calcined catalyst used = 0.1008 g

Concentration of Cu = 10 %wt

Amount of theoretical = /63.54610/1000.1008 mole

% Reducibility = )100(/63.54610/1000.1008

8.7017](0.8777)/ x [1.257x10 -3

= 79.9 %

89

APPENDIX D

HC PRODUCTION

In this research, we studied the methanol steam reforming of over Cu-based

catalysts which prepared by flame spray pyrolysis. The main products of the MSR

reaction were H2, CO2 and CO. Moreover, by-products of MSR containing CH4 and

HC which HC detected in small amounts. Thus, the results of HC formation were

shown in Appendix D.

Figure D.1 HC production on Cu-Al2O3 catalysts in range 200-350 °C.

90

Figure D.2 HC production on Cu-CeO2-Al2O3 catalysts in range 200-350 °C.

Figure D.3 HC production on Cu-ZnO-Al2O3 catalysts in range 200-350 °C.

91

Figure D.4 HC production on Cu-ZnO-CeO2-Al2O3 catalysts in range 200-350 °C.

Figure D.5 HC production on ZnO/Cu-CeO2-Al2O3 catalysts in range 200-350 °C.

92

APPENDIX E

INTERNATIONAL PRESENTATION

Pawinee Eamprapai and Choowong Chaisuk

"Effect of Copper/Alumina Ratio and ZnO promoter in FSP Catalyst on Hydrogen Production from Methanol", 12th International Conference on Atomically Controlled Surfaces, Interfaces and Nanostructuresin conjunction with 21st International Colloquium on Scanning Probe Microscopy (ACSIN-12 & ICSPM21 2013), Tsukuba International Congress Center, Tsukuba, Japan, November 4-8, 2013, Poster presentation.

93

PROFILE

Name: Miss Pawinee Eamprapai

Birth date: February 7, 1989

Place of birth: Nakorn Pathom , Thailand

Nationality: Thai

Religion: Thai

Address: 37 M.4, T. Banluang, A. Dontoom,

Nakorn Pathom, 73150, Thailand

Contact: [email protected], Tel. 0850190329

Education:

2013 Master student of Chemical Engineering at Graduate

School, Silpakorn University.

2010 Bachelor degree of Chemical Engineering, Silpakorn

University.

2006 Kasetsart University Laboratory School Kamphaeng Saen

Campus, Educational Research and Development Center,

Nakorn Pathom,Thailand

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