Nanostructured Bimetallic, Trimetallic and Core-Shell Fuel-CellNanostructured Bimetallic, Trimetallic and Core-Shell Fuel-CellCatalysts with Controlled Size, Composition, and MorphologyCatalysts with Controlled Size, Composition, and Morphology

(NIRT (NIRT CBET-0709113CBET-0709113))Jin LuoJin Luo11, Peter N. Njoki, Peter N. Njoki11, Derrick Mott, Derrick Mott11, Bridgid Wanjala, Bridgid Wanjala11, Rameshwori Loukrakpam, Rameshwori Loukrakpam11, Bin Fang, Bin Fang11, Xiajing Shi, Xiajing Shi11, , Khalid AlzoubiKhalid Alzoubi22,,

Susan LuSusan Lu22, Lichang Wang, Lichang Wang44, Bahgat Sammakia, Bahgat Sammakia33, and , and Chuan-Jian ZhongChuan-Jian Zhong11**, ,

Department of Department of 11Chemistry, Chemistry, 22Systems Science and Industrial Engineering, Systems Science and Industrial Engineering, 33Mechanical Engineering, State University of New York Mechanical Engineering, State University of New York at Binghamton; at Binghamton; 44Department of Chemistry & Biochemistry, Southern Illinois University at Carbondale,Department of Chemistry & Biochemistry, Southern Illinois University at Carbondale, USA USA

Abstract: Active, robust, and low-cost catalyst is a key component for the commercialization of fuel cells. The development of effective strategies for the synthesis and processing of multimetallic nanoparticles with controllable size and composition is an important approach to the catalyst preparation. This poster focuses on the results from an investigation of bimetallic, trimetallic, and core-shell nanoparticle catalysts for fuel cell testing. The characterization of the size, shape, composition and phase properties of the multimetallic nanoparticles and catalysts is described. The electrochemical characterization of the electrocatalytic properties of the catalysts for fuel cell reactions is discussed along with preliminary evaluation of some of the catalysts under fuel cell testing conditions. The results are also discussed in terms of activity and stability of the catalysts based on theoretical computation and statistical optimization to gain fundamental insights into the design and control parameters of fuel cell catalysts.

Fuel Cell and Catalysts

Goals:

Trimetallic Nanoparticles & Catalysts

Relative Mass Activities for ORR

Spot (size) Pt V Fe

10 (area) 34 16 50

11 (3nm) 34 16 50

12 (3nm) 33 15 52

13 (6nm) 32 13 55

Composition 32 13 55 Pt32 V14 Fe54 /C

HTEM-EDX analysis

EDX Analysis of Composition

PtVFe

Comparison of relative electrocatalytic activities. Examples: Pt32V14Fe54/C (31% loading),Pt31Ni34Fe35/C

(30% metal loading) and standard Pt/C (20% metal loading) catalysts. Insert: Rotating Disk Electrode data for catalysts on glassy carbon electrode in 0.5 M H2SO4.

(5 mV/s, and 2000 rpm).

For More Information: Email Contact: * C.J. Zhong: cjzhong@binghamton.edu; Web: http://chemistry.binghamton.edu/ZHONG/zhong.htm

Summary• Bimetallic, trimetallic, and core-shell nanoparticle catalysts with controlled size, composition and phase properties have been shown to exhibit high electrocatalytic activity.• Experimental, theoretical, and statistic analysis results have shown that the size and composition of multimetallic nanoparticles play an important role in regulating the electrocatalytic activity and stability.• These multimetallic nanocatalysts are being characterized and evaluated under fuel cell conditions in terms of activity and durability.

Fuel cell polarization curves of MEA with Pt/C catalyst (20% loading). Pt loading: 1.0 mg/cm2, MEA active area: 5 cm2.

Fuel Cell Testing

SupportReferences1. Luo, J.; Wang, L.; Mott, D.; Njoki, P. N.; Kariuki, N. N.; Zhong, C. J. He, T., J. Mater. Chem., 2006, 16,

1665.2. Luo, J.; Han, L.; Kariuki, N. N.; Wang, L.; Mott, D.; Zhong, C. J.; He, T., Chem. Mater., 2005, 17, 5282.3. D. Mott, J. Luo, P. Njoki, Y. Lin, L. Wang, C. J. Zhong, Catalysis Tod., 2007, 122, 3784. X. Shi, J. Luo, P. Njoki, Y. Lin, T. H. Lin, D. Mott, S. Lu, C. J. Zhong, Ind. Eng. Chem. Res., 2008, 47, 4675.

5. Zhong, C. J.; Luo, J.; Njoki, P. N.; Mott, D.; Wanjala B.; Loukrakpam, R.; Lim, S. I-I.; Wang, L.; Fang, B.;

Xu, Z., Energy & Environ. Sci, 2008, 1, 454.

6. J. Luo, L.Y. Wang, D. Mott, P. Njoki, Y. Lin, T. He, Z. Xu, B. Wanjala, S. I-Im Lim, C. J. Zhong, Adv. Mater.,

in press.

Evaluation of the activity and durability of membrane electrode assembly (MEA) in fuel cells

Characterization of electrocatalytic activity and stability of the multimetallic catalysts using RDE technique Optimization

and Identification of the best catalysts

Preparation of PtVFe Nanoparticles

Preliminary results from density functional theory (DFT) calculations for O2 on PtmVnFel and Pt nanoparticles show that

the oxygen reduction reaction is favorable on PtmVnFel in comparison with Pt due to

direct or spontaneous O2 dissociations. O2

dissociation on PtmVnFel nanoparticles is

limited by the active sites (Pt-V or Pt-Fe) available.

Stability

Selecting M1 and M2 can be based on Pareto optimization plot. A set of solutions is said to be Pareto optimal if it cannot be improved upon without hurting one of the objectives.

PtNiZr

General correlation between two different properties (Activity and Stability) for catalyst (M1)x(M2)yPt1-x-y

Activity

DFT Calculations Optimization Analysis

: frozen states of bulk bimetallic metal system

: data for bulk bimetallic metal system

: bimetallic composition determined from XRD

: bimetallic composition determined from DCP-AES.

Bulk: Nanoscale:

Bimetallic Nanoparticles & Catalysts • High conversion efficiency• Low pollution• Light weight• High power density

Fuel cell voltage: Ecell = ENernst +

ηact (i.e., ηact(cathode) - ηact(anode)) – ηohmic FTIR of CO Adsorption on AunPt100-n/SiO2

XRD of AunPt100-n/C

ORR: Oxygen Reduction Reaction

Optimal balanced activity and stability for (Ni)x(Zr)yPt1-x-y

}

+

Pareto optimizationPareto optimization

Core-Shell Catalysts

Existing Catalysts:• Low activity• High Pt loading (high cost)• Poor stability

• Reduce Pt loading• Increase activity & stability• Understand design parameters • Discover new catalysts

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