Application of surface photovoltage technique in photocatalysis studies onmodified TiO2 photo-catalysts for photo-reduction of CO2

Surface photovoltage spectrum (SPS) is a useful technique in photocatalysis studies. Here, the relationship between the catalytic activities of modifi ed TiO2, which are composed of Pd/RuO2/TiO2 (A), Pd/TiO2 (B), a-TiO2 (C) an d b-TiO2 (D) for photoreduction of CO2 and surface photovoltage (SPV) respo nse was studied by means of this technique. The SPV response increased afte r surface noble metal (Pd and Ru) depositing and a new SPV response band ap peared in the SPS curve of A and B in near IR, which was attributed to the surface state population transition formed by Pd deposition. Corresponding to SPV response, the catalytic activity of photoreduction of CO2 improved a fter surface noble metal (Pd and Ru) depositing. Moreover, the stronger SPV response is, the higher the catalytic activity of photoreduction of CO2 is . The effect of metal depositing on the behavior of photo-generated carrier s in TiO2 semiconductor photocatalysts, as well as the mechanism on photore duction CO2 of A was discussed. (C) 2001 Elsevier Science B.V. All rights r eserved.