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

Abstract

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 H₂ with high selectivity (>99.9%).