Visible light-induced hydrogen over CuFeO2 via S2O2 3 oxidation

The properties of CuFeO2 have been studied according to the catalytic hydrogen production upon visible light. CuFeO2 with a low band gap Eg, a good chemical stability and a suitable flat band potential appears as a suitable candidate. The potential of photoelectrons allows favorably a thermodynamically H2-evolution from alkaline thiosulfate S2O2 3 solution. There is a major difference between pure and loaded oxide with some metal catalysts. Our best results have been obtained with unloaded CuFeO2 at 50 C and pH 13.60. Thiosulfate S2O2 3 ions can be oxidized to sulfite SO2 3 and subsequently to sulfate SO2 4 and the electronic exchange occurs via mediation of surface states. The quite high H2-formation at the beginning shows a tendency towards saturation, it competes with SO2 3 produced by parallel oxidation of S2O2 3 . 2004 Published by Elsevier Ltd