Research in Solar Generation of Fuels with the Mullins Group

(updated July 25, 2014)

Prof. Buddie Mullins Chemical Engineering

& Chemistry

UT-Austin

mullins@che.utexas.edu

(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