Research in Solar Generation of Fuels with the Mullins Group
(updated July 25, 2014)
Prof. Buddie Mullins Chemical Engineering
& Chemistry
UT-Austin
(512) 471-5817
http://research.engr.utexas.edu/mullins//
Participating Graduate Students
Niyi
Mabayoje
Will
Chemelewski
Jiayong
Gan visiting from
Sun Yat-Sen
University
Alex
Rettie
Our Solar Research is Supported by the DOE
and the Welch Foundation.
Undergraduate Solar PhotoElectroChemistry Researchers
Heather
Bolton
Jacob
Rosenstock
Distinguished Collaborator
We collaborate with Professor Allen
J. Bard and his research group on
solar fuel generation research. We
also share grants with Prof. Bard
related to this research.
http://bard.cm.utexas.edu/ 2
Solar Generation of Fuels Research Goals
Discovery of Improved
Photomaterials and Electrocatalysts
for Solar Water Splitting.
The training of graduate students for
productive research careers in the
chemical industry, national
laboratories, and academia.
Enhanced Understanding of the
Physical Processes in
PhotoElectroChemistry (PEC).
Modified from K. Sivula et al. ChemSusChem 2011, 4, 432-449. http://onlinelibrary.wiley.com/doi/10.1002/cssc.201000416/abstract
BiOI nanoflakes: ACS Nano 6, 7712-7722(2012). http://dx.doi.org/10.1021/nn3031063
http://www.space.com/12502-sun-smiley-face-video-sunspots.html 4
How Does Solar Water Splitting Work?
5
hn h+
n-type
semiconductor
photoanode
e-
cat.
H2O + 4h+
O2 + 4H+
C
A
T
H
O
D
E
cat.
4e- + 4H+
2H2 5
1
1
2
2
3
3
4
4
Sunlight with energy
above the
semicondcutor band
gap is absorbed.
An electron (e-)
and hole (h+ -
absence of an
electron) pair are
created.
An electric field in
the material at the
solid-liquid interface
separates the
charges moving the
hole toward the
solid-liquid
interface.
The holes that are produced move to
the oxygen evolution reaction
electrocatalyst and convert water to O2.
Electrons move to the hydrogen
evolution reaction (HER) electrocatalyst
and reduce protons to H2. 5
Research Activities Current Research Interests Include:
Discovery of Photomaterials and
Favorable Morphologies:
Electrocatalysts for the proton
reduction and oxygen evolution
reactions.
Characterization of charge carrier
transport in metal oxide
semiconductors.
Design of Devices:
6
Publications from 2012 -7 July 2014 Huichao He, Sean P. Berglund, Alexander J. E. Rettie, William D. Chemelewski, Peng Xiao, Yunhuai Zhang, and C. Buddie Mullins, “Synthesis of
BiVO4 nanoflake array films for photoelectrochemical water oxidation,” J. Mater. Chem. A. 2, 9371-9379 (2014).
http://dx.doi.org/10.1039/C4TA00895B
Yiqing Sun, William D. Chemelewski, Sean P. Berglund, Chun Li, Huichao He, Gaoquan Shi, and C. Buddie Mullins, “Antimony doped tin oxide
nanorods as a transparent conducting electrode for enhancing photoelectrochemical oxidation of water by hematite,” ACS Appl. Mater.
Interfaces 6, 5494-5499 (2014). http://dx.doi.org/10.1021/am405628r
Stephen E. Fosdick, Sean P. Berglund, C. Buddie Mullins, and Richard M. Crooks, “Evaluating electrocatalysts for the hydrogen evolution
reaction based on bi- and trimetallic combinations of Co, Fe, Ni, Mo, and W using bipolar electrode arrays,” ACS Catal. 4, 1332-1339 (2014).
http://dx.doi.org/10.1021/cs400168t
Alexander J. E. Rettie, Kyle C. Klavetter, Jung-Fu Lin, Andrei Dolocan, Hugo Celio, Ashioma Ishiekwene, Heather L. Bolton, Kristen N. Pearson,
Nathan T. Hahn, and C. Buddie Mullins, “Improved visible light harvesting of WO3 by incorporation of sulfur or iodine: A tale of two
impurities,” Chem. Mater. 26, 1670-1677 (2014). http://dx.doi.org/10.1021/cm403969r
William C. Chemelewski, Heung-Chan Lee, Allen J. Bard, and C. Buddie Mullins, “Amorphous FeOOH Oxygen Evolution Reaction Catalyst
for Photoelectrochemical Water Splitting,” J. Am. Chem. Soc. 136, 2843-2850 (2014). http://dx.doi.org/10.1021/ja411835a
Sean P. Berglund, Huichao He, William D. Chemelewski, Hugo Celio, and C. Buddie Mullins, “p-Si/W2C and p-Si/W2C/Pt photocathodes for
the hydrogen evolution reaction,” J. Am. Chem. Soc. 136, 1535-1544 (2014). http://dx.doi.org/10.1021/ja411604k
Sean P. Berglund, Son Hoang, Ryan L. Minter, Raymond R. Fullon, and C. Buddie Mullins, “Investigation of 35 elements as single metal oxides,
mixed metal oxides, or dopants for titanium dioxide for dye-sensitized solar cells,” J. Phys. Chem. C. 117, 25248-25258 (2013).
http://dx.doi.org/10.1021/jp4073747
Huichao He, Sean P. Berglund, Peng Xiao, William D. Chemelewski, Yunhuai Zhang, and C. Buddie Mullins, “Nanostructured Bi2S3/WO3
heterojunction films exhibiting enhanced photoelectrochemical performance,” J. Mater. Chem. A. 1, 12826-12834 (2013).
http://dx.doi.org/10.1039/C3TA13239K
Thong Q. Ngo, Agham Posadas, Hosung Seo, Son Hoang, Martin D. McDaniel, A. Posadas, H. Seo, Dirk Utess, Dina H. Triyoso, C. Buddie
Mullins, Alexander A. Demkov, John G. Ekerdt, “Atomic layer deposition of photoactive CoO/SrTiO3 and CoO/TiO2 on Si(001) for visible
light driven photoelectrochemical water oxidation,” J. Appl. Phys. 114, 084901 (2013). http://dx.doi.org/10.1063/1.4819106
7
Publications from 2012 - July 2014 - II
Alexander J. E. Rettie, Heung-Chan Lee, Luke G. Marshall, Jung-Fu Lin, Cigdem Capan, Jeffrey Lindemuth, John S. McCloy, Jianshi Zhou, Allen J.
Bard, and C. Buddie Mullins, "Combined charge carrier transport and photoelectrochemical characterization of BiVO4 single crystals:
Intrinsic behavior of a complex metal oxide," J. Am. Chem. Soc. 135, 11389-11396 (2013). http://dx.doi.org/10.1021/ja405550k
Chao Liu, Xiaobin Xu, Alexander J. E. Rettie, C. Buddie Mullins, and D. L. Fan, "One-step waferscale synthesis of 3-D ZnO
nanosuperstructures by designed catalysts for substantial improvement of solar water oxidation efficiency," J. Mater. Chem. A 1, 8111-8117
(2013). http://dx.doi.org/10.1039/C3TA11462G
Son Hoang, Thong Q. Ngo, Sean P. Berglund, Raymond R. Fullon, John G. Ekerdt, and C. Buddie Mullins, “Improvement of solar energy
conversion with Nb-incorporated TiO2 hierarchical microspheres,” ChemPhysChem 14, 2270-2276 (2013).
http://dx.doi.org/10.1002/cphc.201201092
Sean P. Berglund, Heung Chan Lee, Paul D. Nunez, Allen J. Bard, and C. Buddie Mullins, “Screening of transition and post-transition metals to
incorporate into copper oxide and copper bismuth oxide for photoelectrochemical hydrogen evolution,” Phys. Chem. Chem. Phys. 15, 4554-
4565 (2013). http://dx.doi.org/10.1039/C3CP50540E
Son Hoang, Sean P. Berglund, Raymond R. Fullon, Ryan L. Minter, and C. Buddie Mullins, "Chemical bath deposition of vertically aligned TiO2
nanoplatelet arrays for solar energy conversion applications," J. Mater. Chem. A. 1, 4307-4315 (2013). http://dx.doi.org/10.1039/C3TA01384G
Stephen E. Fosdick, Sean P. Berglund, C. Buddie Mullins, and Richard M. Crooks, “Parallel screening of electrocatalyst candidates using bipolar
electrochemistry,” Anal. Chem. 85, 2493-2499 (2013). http://dx.doi.org/10.1021/ac303581b
Nathan T. Hahn, Alexander J. E. Rettie, Susanna K. Beal, Raymond R. Fullon, and C. Buddie Mullins, "n-BiSI thin films: Selenium doping and solar
cell behavior," J. Phys. Chem. C. 116, 24878-24886 (2012). http://dx.doi.org/10.1021/jp3088397
Son Hoang, Siwei Guo, and C. Buddie Mullins, “Co-incorporation of Ta, N into TiO2 nanowires for visible-light driven photoelectrochemical
water oxidation,” J. Phys. Chem. C 116, 23283-23290 (2012). http://dx.doi.org/10.1021/jp309743u
Hoang X. Dang, Hyun S. Park, Nathan T. Hahn, Allen J. Bard, and C. Buddie Mullins, “Nanostructured Ta3N5 Films as Visible-Light Active
Photoanodes for Water Oxidation,” J. Phys. Chem. C 116, 19225-19232 (2012). http://dx.doi.org/10.1021/jp307369z
8
Publications from 2012 - July 2014 - III
Nathan T. Hahn, Son Hoang, Jeffrey L. Self, and C. Buddie Mullins, "Spray pyrolysis deposition and photoelectrochemical properties of n-type
BiOI nano-platelet thin films," ACS Nano 6, 7712-7722 (2012). http://dx.doi.org/10.1021/nn3031063
Yanqing Cong, Shijun Wang, Hoang X. Dang, Fu-Ren F. Fan, C. Buddie Mullins, and Allen J. Bard, “Synthesis of Ta3N5 nanotube arrays modified
with electrocatalysts for photoelectrochemical water oxidation,” J. Phys. Chem. C 116, 14541-14550 (2012).
http://dx.doi.org/10.1021/jp304340a
Nathan T. Hahn, Jeffrey L. Self, and C. Buddie Mullins, "BiSI micro-rod thin films: Efficient solar absorber electrodes?," J. Phys. Chem. Lett. 3,
1571-1576 (2012). http://dx.doi.org/10.1021/jz300515p
Sean P. Berglund, Alex J. E. Rettie, Son Hoang, and C. Buddie Mullins, “Incorporation of Mo and W into Nanostructured BiVO4 Films to
Improve Photoelectrochemical Water Oxidation Performance,” Phys. Chem. Chem. Phys. 14, 7065-7075 (2012).
http://dx.doi.org/10.1039/C2CP40807D
Nathan T. Hahn, Vincent C. Holmberg, Brian A. Korgel, and C. Buddie Mullins, “Electrochemical synthesis and characterization of p-CuBi2O4
thin film photocathodes,” J. Phys. Chem. C 116, 6459-6466 (2012). http://dx.doi.org/10.1021/jp210130v
Son Hoang, Sean P. Berglund, Nathan T. Hahn, Allen J. Bard, and C. Buddie Mullins, "Enhancing visible light photo-oxidation of water with TiO2
nanowire arrays via co-treatment with H2 and NH3: Synergistic effects between Ti3+ and N," J. Am. Chem. Soc. 134, 3659-3662 (2012).
http://dx.doi.org/10.1021/ja211369s
William D. Chemelewski, Nathan T. Hahn, and C. Buddie Mullins, “The effect of Si doping and porosity on Hematite’s (a-Fe2O3)
photoelectrochemical water oxidation performance,” J. Phys. Chem. C 116, 5255-5261 (2012). http://dx.doi.org/10.1021/jp210877u
Yanqing Cong, Hyun S. Park, Hoang X. Dang, Fu-Ren F. Fan, Allen J. Bard, C. Buddie Mullins, “Tantalum Cobalt Nitride Photocatalysts for
Water Oxidation under Visible Light,” Chem. Mater. 24, 579-586 (2012). http://dx.doi.org/10.1021/cm203269n
Son Hoang, Siwei Guo, Nathan T. Hahn, Allen J. Bard, and C. Buddie Mullins, “Visible-light Driven Photoelectrochemical Water Oxidation on
Nitrogen-doped TiO2 Nanowires,” Nano Lett. 12, 26-32 (2012). http://dx.doi.org/10.1021/nl2028188
9
Solar PhotoElectroChemistry Lab Recent Alumni
Nathan Hahn
Ph.D. Aug. 2012
Sandia National Lab
Recently Graduated Ph.D. Students
Son Hoang
Ph.D. May 2013
Brookhaven
National Lab
Sean Berglund
Ph.D. Dec. 2013
Helmholtz Zentrum
Berlin
Former Undergraduate Researchers
Siwei Guo
now at GaTech
Kristen Pearson Paul Nunez
now at Caltech
Jeff Self Sam Morehead Sybil Wong
10
Solar PEC Lab Photo Gallery
11
Sean Berglund and Son Hoang in the lab. Nathan Hahn and Hoang Dang with one of our
first reactive ballistic deposition machines.
Will Chemelewski in the lab making
measurements. Sean Berglund and Paul Nunez
in the early stages of building
our rapid synthesis and scanning
apparatus.
Solar PEC Lab Photo Gallery II
12
With the theme, “Let’s mock Buddie’s photo with goofy water filled beaker!”
Buddie Mullins with goofy water filled beaker
(water-splitting!) as instructed by UT photographer.
Will carefully studies water spilling (not splitting)
from beakers held by Alex, Jiayong, and Niyi. Will Chemelewski resting with water filled beaker.
Will, Alex, Jiayong, and Niyi with their
water filled beakers.
13
Melissa and Siwei Guo working in PEC lab. Nathan Hahn and Alex Rettie grow a film
by reactive ballistic deposition.
Sean Berglund using one of the
reactive ballistic deposition machines. Son Hoang in the lab leading “Team Titania.”
Solar PEC Lab Photo Gallery III
14
Solar PEC Lab Photo
Gallery IV With the theme, “Let’s mock squirrely photo of Buddie
explaining glancing angle deposition!”
Alex Rettie “explains” glancing angle
deposition to Hoang Dang and Will
Chemelewski.
15
Solar PEC Lab Photo Gallery IV
Alex Rettie on a very good day!
16
Mullins Research Group Photo – April 2014