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

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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 languageEnglish
Pages (from-to)5694-5700
Number of pages7
JournalEnergy and Environmental Science
Issue number2
Publication statusPublished - Feb 1 2012


ASJC Scopus subject areas

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

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