Photoelectrochemical Hydrogen Peroxide Production from Water on a WO /BiVO Photoanode and from O on an Au Cathode Without External Bias.

The photoelectrochemical production and degradation properties of hydrogen peroxide (H O ) were investigated on a WO /BiVO photoanode in an aqueous electrolyte of hydrogen carbonate (HCO ). High concentrations of HCO species rather than CO species inhibited the oxidative degradation of H O on the WO /BiVO photoanode, resulting in effective oxidative H O generation and accumulation from water (H O). Moreover, the Au cathode facilitated two-electron reduction of oxygen (O ), resulting in reductive H O production with high current efficiency. Combining the WO /BiVO photoanode with a HCO electrolyte and an Au cathode also produced a clean and promising design for a photoelectrode system specializing in H O production (η (H O )≈50 %, η (H O )≈90 %) even without applied voltage between the photoanode and cathode under simulated solar light through a two-photon process; this achieved effective H O production when using an Au-supported porous BiVO photocatalyst sheet.