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.
ASJC Scopus subject areas
- Environmental Chemistry
- Renewable Energy, Sustainability and the Environment
- Nuclear Energy and Engineering