A ZnTa2O6 photocatalyst synthesized via solid state reaction for conversion of CO2 into CO in water

Because of the environmental problems and the resulting exigent demand for CO2 recycling processes, great attention is being paid to the photocatalytic conversion of CO2 into useful chemicals such as CO, HCOOH, HCHO, CH3OH, and CH4. We have previously reported that the Ag-loaded, Zn-modified Ga2O3 photocatalyst exhibits excellent photocatalytic activity required for the conversion of CO2 into CO by using H2O as a reductant and that the Ag particles that exist together with the Zn species act as good cocatalysts for the selective formation of CO. In this study, we demonstrated the photocatalytic activity of ZnTa2O6 under UV light irradiation, which was prepared via solid-state reaction, for the conversion of CO2 in an aqueous NaHCO3 solution. A Ag cocatalyst-loaded ZnTa2O6 photocatalyst evolved CO as a reduction product of CO2 with 46% selectivity toward CO evolution among the reduction products. In contrast, when Pt and Au were introduced as cocatalysts, the ZnTa2O6 photocatalyst evolved H-2 with high selectivity (> 99.9%).