First-principles study of photocatalytic mechanism and charge transfer of PtS2/MoSe2 S-scheme heterojunction

In this work, the PtS2/MoSe2 heterojunction was verified as a S-scheme heterojunction with strong redox ability by density functional theory calculations. Firstly, the band structure and density of states of PtS2/MoSe2 heterojunction are systematically investigated. The results show that the band gap of the PtS2/MoSe2 heterojunction is effectively narrowed compared to the pristine semiconductor, resulting in a red shift of the absorption edge; then, According to the analysis of work function, the height difference of the Fermi level induces the spontaneous flow of electrons, resulting in band bending and the establishment of the built-in electric field, which will promote the recombination (separation) of electron-hole pairs with weak (strong) redox ability at the interface. The carriers with strong redox ability are effectively separated and preserved, which prolongs the lifetime of photogenerated carriers and improves the photocatalytic efficiency.