H2O2production on a carbon cathode loaded with a nickel carbonate catalyst and on an oxide photoanode without an external bias

Abstract

Efficient H2O2production both on a carbon cathode modified with various metal salts and on an oxide photoanode was investigated. The cathodic current density and faradaic efficiency for H2O2production (FE(H2O2)) on a carbon cathode in KHCO3aqueous solution were significantly improved by the loading of an insoluble nickel carbonate basic hydrate catalyst. This electrode was prepared by a precipitation method of nickel nitrate and KHCO3aqueous solution at ambient temperature. The nickel carbonate basic hydrate electrode was very stable, and the accumulated concentration of H2O2was reached at 1.0 wt% at a passed charge of 2500C (the average FE(H2O2) was 80%). A simple photoelectrochemical system for H2O2production from both the cathode and a BiVO4/WO3photoanode was demonstrated without an external bias or an ion-exchange membrane in a one-compartment reactor under simulated solar light. The apparent FE(H2O2) from both electrodes was calculated to be 168% in total, and the production rate of H2O2was approximately 0.92 μmol min−1cm−2. The solar-to-chemical energy conversion efficiency for H2O2production (STCH2O2) without an external bias was approximately 1.75%.