Surface gallium oxide hydroxide species adsorbing carbon dioxide to enhance the photocatalytic activity of silver-loaded calcium titanate for carbon dioxide reduction with water

Photocatalytic conversion of carbon dioxide (CO2) has attracted considerable attention as a new method to build a carbon cycle. Particularly, photocatalytic reduction of CO2 using water as an electron and proton donor to yield carbon monoxide (CO) is quite valuable but challenging, where enhancement of CO2 adsorption on the photocatalyst surface may contribute to increasing the photocatalytic reaction rate. In this viewpoint, the surface modification was examined for an Ag/CTO photocatalyst that can promote CO2 reduction with water selectively, i.e., an Ag/GaOOH/CTO photocatalyst was prepared by a step-by-step loading method. As a result, the GaOOH species deposited on CaTiO3 with Ag NPs endowed the photocatalyst with enhanced CO2 adsorption properties to increase the CO yield more than 5 times. This short paper provides one of the strategies to improve the photocatalytic properties of CO2 reduction with water. GaOOH as a good CO2 adsorber works together with Ag NPs to improve photocatalytic CO2 reduction by a CaTiO3 photocatalyst.