Efficient reduction of CO 2 to CO by Ag 3 PO 4 /TiO 2 photocatalyst under ultraviolet and visible light irradiation

Efficient conversion of carbon dioxide (CO 2 ) into energy‐bearing compounds using abundant solar energy is a promising technique that simultaneously responds to the concerns on global warming and energy shortage. The purpose of this study was to find a photocatalyst that can efficiently utilize sunlight for an efficient reduction of CO 2 to energy‐bearing carbon monoxide (CO). Silver phosphate/titanium dioxide (Ag 3 PO 4 /TiO 2 ) hetero‐structured photocatalysts with different mole ratios of Ag 3 PO 4 to TiO 2 were synthesized by a facile precipitation method, and for the first time used for photocatalytic CO 2 reduction by water vapor (H 2 O). When the mole ratio of Ag3PO4 to TiO 2 was 0.15, the as‐synthesized photocatalyst exhibited the highest CO 2 reduction activity under ultraviolet (UV) and visible light irradiation, with the productivity of CO reaching as high as 74.84 μmol·g −1 within a 3‐h experiment. This is 3.5 and 11.7 times higher than that for the bare Ag 3 PO 4 and TiO 2 , respectively. The characterization results indicate that a heterojunction was formed between Ag 3 PO 4 and TiO 2 , which significantly promoted the photocatalytic CO 2 reduction reactions through facilitating the separation and migration of the photogenerated charge carriers. This study verified that the Ag 3 PO 4 /TiO 2 catalyst can effectively utilize solar energy for reduction of CO 2 to CO.