Abstract
Cd1-xZnxS solid solutions with strong light absorption are promising materials for solar-driven CO2 re-duction;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 struc-ture to construct a S-scheme photocatalytic system can solve both problems simultaneously.Here,we report a S-scheme photocatalyst based on the heterostructure of CoTiO3/Cd9.51Zn0.49S10(abbreviated as CoTiO3/CdZnS)that enables the efficient photocatalytic reduction of CO2.Detailed physicochemical char-acterization 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 ab-sorption in a broad spectral region,large surface area,strong redox ability,and fast carrier separation and transportation.Under visible-light illumination,the CoTiO3/CdZnS hybrid system displays a CO formation rate of about 11 mmol h-1 g-1 combined with a long-term operational stability.Besides,a high appar-ent quantum efficiency(AQE)of 7.27％is realized for the CO2-to-CO reduction reaction by the optimized CoTiO3/CdZnS hybrid under 420 nm monochromatic light irradiation.
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