Selective CO2 Conversion to Formate Conjugated with H2O Oxidation Utilizing Semiconductor/Complex Hybrid Photocatalysts

Photoelectrochemical reduction of CO2 to HOO- (formate) over p-type InP/Ru complex polymer hybrid photo catalyst was highly enhanced by introducing an anchoring complex into the polymer. By functionally combining the hybrid photocatalyst with TiO2 for water oxidation, selective photoreduction of CO2 to HCOO- was achieved in aqueous media, in which H2O was used as both an electron donor and a proton source. The so-called Z-scheme (or two-step photoexcitation) system operated with no external electrical bias. The selectivity for HCOO- production was >70%, and the conversion efficiency of solar energy to chemical energy was 0.03-0.04%.