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Title: Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi 2O 4 and Ag-Doped CuBi 2O 4 Photocathodes

Here, electrochemical synthesis methods were developed to produce CuBi 2O 4, a promising p-type oxide for use in solar water splitting, as high surface area electrodes with uniform coverage. These methods involved electrodepositing nanoporous Cu/Bi films with a Cu:Bi ratio of 1:2 from dimethyl sulfoxide or ethylene glycol solutions, and thermally oxidizing them to CuBi 2O 4 at 450°C in air. Ag-doped CuBi 2O 4 electrodes were also prepared by adding a trace amount of Ag+ in the plating medium and codepositing Ag with the Cu/Bi films. In the Ag-doped CuBi 2O 4, Ag+ ions substitutionally replaced Bi3+ ions and increased the hole concentration in CuBi 2O 4. As a result, photocurrent enhancements for both O 2 reduction and water reduction were achieved. Furthermore, while undoped CuBi 2O 4 electrodes suffered from anodic photocorrosion during O 2 reduction due to poor hole transport, Ag-doped CuBiO 4 effectively suppressed anodic photocorrosion. The flat-band potentials of CuBi 2O 4 and Ag-doped CuBi 2O 4 electrodes prepared in this study were found to be more positive than 1.3 V vs RHE in a 0.1 M NaOH solution (pH 12.8), which make these photocathodes highly attractive for use in solar hydrogen production. The optimizedmore » CuBi 2O 4/Ag-doped CuBi 2O 4 photocathode showed a photocurrent onset for water reduction at 1.1 V vs RHE, achieving a photovoltage higher than 1 V for water reduction. The thermodynamic feasibility of photoexcited electrons in the conduction band of CuBi 2O 4 to reduce water was also confirmed by detection of H 2 during photocurrent generation. This study provides new understanding for constructing improved CuBi 2O 4 photocathodes by systematically investigating photocorrosion as well as photoelectrochemical properties of high-quality CuBi 2O 4 and Ag-doped CuBi 2O 4 photoelectrodes for photoreduction of both O 2 and water.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1]
  1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Chemistry
  2. Purdue Univ., West Lafayette, IN (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0008707
Type:
Published Article
Journal Name:
Chemistry of Materials
Additional Journal Information:
Journal Volume: 28; Journal Issue: 12; Journal ID: ISSN 0897-4756
Publisher:
American Chemical Society (ACS)
Research Org:
Univ. of Wisconsin, Madison, WI (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE
OSTI Identifier:
1328579
Alternate Identifier(s):
OSTI ID: 1438028

Kang, Donghyeon, Hill, James C., Park, Yiseul, and Choi, Kyoung-Shin. Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes. United States: N. p., Web. doi:10.1021/acs.chemmater.6b01294.
Kang, Donghyeon, Hill, James C., Park, Yiseul, & Choi, Kyoung-Shin. Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes. United States. doi:10.1021/acs.chemmater.6b01294.
Kang, Donghyeon, Hill, James C., Park, Yiseul, and Choi, Kyoung-Shin. 2016. "Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes". United States. doi:10.1021/acs.chemmater.6b01294.
@article{osti_1328579,
title = {Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes},
author = {Kang, Donghyeon and Hill, James C. and Park, Yiseul and Choi, Kyoung-Shin},
abstractNote = {Here, electrochemical synthesis methods were developed to produce CuBi2O4, a promising p-type oxide for use in solar water splitting, as high surface area electrodes with uniform coverage. These methods involved electrodepositing nanoporous Cu/Bi films with a Cu:Bi ratio of 1:2 from dimethyl sulfoxide or ethylene glycol solutions, and thermally oxidizing them to CuBi2O4 at 450°C in air. Ag-doped CuBi2O4 electrodes were also prepared by adding a trace amount of Ag+ in the plating medium and codepositing Ag with the Cu/Bi films. In the Ag-doped CuBi2O4, Ag+ ions substitutionally replaced Bi3+ ions and increased the hole concentration in CuBi2O4. As a result, photocurrent enhancements for both O2 reduction and water reduction were achieved. Furthermore, while undoped CuBi2O4 electrodes suffered from anodic photocorrosion during O2 reduction due to poor hole transport, Ag-doped CuBiO4 effectively suppressed anodic photocorrosion. The flat-band potentials of CuBi2O4 and Ag-doped CuBi2O4 electrodes prepared in this study were found to be more positive than 1.3 V vs RHE in a 0.1 M NaOH solution (pH 12.8), which make these photocathodes highly attractive for use in solar hydrogen production. The optimized CuBi2O4/Ag-doped CuBi2O4 photocathode showed a photocurrent onset for water reduction at 1.1 V vs RHE, achieving a photovoltage higher than 1 V for water reduction. The thermodynamic feasibility of photoexcited electrons in the conduction band of CuBi2O4 to reduce water was also confirmed by detection of H2 during photocurrent generation. This study provides new understanding for constructing improved CuBi2O4 photocathodes by systematically investigating photocorrosion as well as photoelectrochemical properties of high-quality CuBi2O4 and Ag-doped CuBi2O4 photoelectrodes for photoreduction of both O2 and water.},
doi = {10.1021/acs.chemmater.6b01294},
journal = {Chemistry of Materials},
number = 12,
volume = 28,
place = {United States},
year = {2016},
month = {6}
}