S-scheme CoTiO_(3)/Cd_(9.51)Zn_(0.49)S_(10)heterostructures for visible-light driven photocatalytic CO_(2) reduction

CdZnS solid solutions with strong light absorption are promising materials for solar-driven COreduction;however,their relatively weak redox ability and intrinsic photo-corrosion limit their further development as a photocatalyst.The addition of a second photocatalyst with a suitable band structure to construct a S-scheme photocatalytic system can solve both problems simultaneously.Here,we report a S-scheme photocatalyst based on the heterostructure of CoTiO_(3)/CdZnS(abbreviated as CoTiO_(3)/Cd_(9.51)Zn_(0.49)S_(10))that enables the efficient photocatalytic reduction of CO.Detailed physicochemical characterization resolves the S-scheme charge transfer mechanism in this composite photocatalyst.With the well-designed structure of particles and desirable band offsets,this hybrid system offers visible light absorption in a broad spectral region,large surface area,strong redox ability,and fast carrier separation and transportation.Under visible-light illumination,the CoTiO_(3)/Cd Zn S hybrid system displays a CO formation rate of about 11 mmol hgcombined with a long-term operational stability.Besides,a high apparent quantum efficiency(AQE)of 7.27%is realized for the CO_(2)-to-CO reduction reaction by the optimized Co TiO/Cd Zn S hybrid under 420 nm monochromatic light irradiation.