A quantitative assessment of the competition between water and anion oxidation at WO 3 photoanodes in acidic aqueous electrolytes

Qixi Mi; Almagul Zhanaidarova; Bruce S. Brunschwig; Harry B. Gray; Nathan S. Lewis

doi:10.1039/c2ee02929d

A quantitative assessment of the competition between water and anion oxidation at WO ₃ photoanodes in acidic aqueous electrolytes

Qixi Mi, Almagul Zhanaidarova, Bruce S. Brunschwig, Harry B. Gray, Nathan S. Lewis

California Institute of Technology

Research output: Contribution to journal › Article › peer-review

207 Citations (Scopus)

Abstract

The faradaic efficiency for O ₂(g) evolution at thin-film WO ₃ photoanodes has been evaluated in a series of acidic aqueous electrolytes. In 1.0 M H ₂SO ₄, persulfate was the predominant photoelectrochemical oxidation product, and no O ₂ was detected unless catalytic quantities of Ag ⁺(aq) were added to the electrolyte. In contact with 1.0 M HClO ₄, dissolved O ₂ was observed with nearly unity faradaic efficiency, but addition of a hole scavenger, 4-cyanopyridine N-oxide, completely suppressed O ₂ formation. In 1.0 M HCl, Cl ₂(g) was the primary oxidation product. These results indicate that at WO ₃ photoanodes, water oxidation is dominated by oxidation of the acid anions in 1.0 M HCl, H ₂SO ₄, and HClO ₄, respectively.

Original language	English
Pages (from-to)	5694-5700
Number of pages	7
Journal	Energy and Environmental Science
Volume	5
Issue number	2
DOIs	https://doi.org/10.1039/c2ee02929d
Publication status	Published - Feb 2012

ASJC Scopus subject areas

Environmental Chemistry
Renewable Energy, Sustainability and the Environment
Nuclear Energy and Engineering
Pollution

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title = "A quantitative assessment of the competition between water and anion oxidation at WO 3 photoanodes in acidic aqueous electrolytes",

abstract = "The faradaic efficiency for O 2(g) evolution at thin-film WO 3 photoanodes has been evaluated in a series of acidic aqueous electrolytes. In 1.0 M H 2SO 4, persulfate was the predominant photoelectrochemical oxidation product, and no O 2 was detected unless catalytic quantities of Ag +(aq) were added to the electrolyte. In contact with 1.0 M HClO 4, dissolved O 2 was observed with nearly unity faradaic efficiency, but addition of a hole scavenger, 4-cyanopyridine N-oxide, completely suppressed O 2 formation. In 1.0 M HCl, Cl 2(g) was the primary oxidation product. These results indicate that at WO 3 photoanodes, water oxidation is dominated by oxidation of the acid anions in 1.0 M HCl, H 2SO 4, and HClO 4, respectively.",

author = "Qixi Mi and Almagul Zhanaidarova and Brunschwig, {Bruce S.} and Gray, {Harry B.} and Lewis, {Nathan S.}",

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T1 - A quantitative assessment of the competition between water and anion oxidation at WO 3 photoanodes in acidic aqueous electrolytes

AU - Mi, Qixi

AU - Zhanaidarova, Almagul

AU - Brunschwig, Bruce S.

AU - Gray, Harry B.

AU - Lewis, Nathan S.

PY - 2012/2

Y1 - 2012/2

N2 - The faradaic efficiency for O 2(g) evolution at thin-film WO 3 photoanodes has been evaluated in a series of acidic aqueous electrolytes. In 1.0 M H 2SO 4, persulfate was the predominant photoelectrochemical oxidation product, and no O 2 was detected unless catalytic quantities of Ag +(aq) were added to the electrolyte. In contact with 1.0 M HClO 4, dissolved O 2 was observed with nearly unity faradaic efficiency, but addition of a hole scavenger, 4-cyanopyridine N-oxide, completely suppressed O 2 formation. In 1.0 M HCl, Cl 2(g) was the primary oxidation product. These results indicate that at WO 3 photoanodes, water oxidation is dominated by oxidation of the acid anions in 1.0 M HCl, H 2SO 4, and HClO 4, respectively.

AB - The faradaic efficiency for O 2(g) evolution at thin-film WO 3 photoanodes has been evaluated in a series of acidic aqueous electrolytes. In 1.0 M H 2SO 4, persulfate was the predominant photoelectrochemical oxidation product, and no O 2 was detected unless catalytic quantities of Ag +(aq) were added to the electrolyte. In contact with 1.0 M HClO 4, dissolved O 2 was observed with nearly unity faradaic efficiency, but addition of a hole scavenger, 4-cyanopyridine N-oxide, completely suppressed O 2 formation. In 1.0 M HCl, Cl 2(g) was the primary oxidation product. These results indicate that at WO 3 photoanodes, water oxidation is dominated by oxidation of the acid anions in 1.0 M HCl, H 2SO 4, and HClO 4, respectively.

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