天津大学研究生e-Learning平台

Metal sulfide semiconductor has wide light response range and suitable energy band structure, which is favorable for photocatalytic CO₂ reduction [1,2]. In this paper, Cu₃SnS₄ photocatalyst was prepared by hydrothermal precipitation method. The successful formation of S vacancy resulted in partial reduction of Cu(II) and Sn(IV) to Cu(I) and Sn(II) in the low state, and the ratio of Cu(I/II) and Sn(II/IV) were adjustable. Regulating the content of Sn(II) can effectively regulate the conduction band position of Cu₃SnS₄, improve the reduction driving force of electrons in the conduction band, and effectively reduce the electron-hole recombination rate. Density functional theory (DFT) calculation showed that Cu(I) and Sn(IV), as the active sites for the adsorption and reaction of CO₂ and H₂O, respectively, achieved 22.65 μmol/g/h and ~ 83.10 % CH₄ yield and selectivity. DFT calculation combined with in situ infrared characterization revealed and proved the photocatalytic CO₂ reduction reaction path. This study provides a new idea and insight on how to improve the selectivity and yield of photocatalytic CO₂ reduction to CH₄ by regulating the metal active sites of metal sulfides.