Theoretical design of direct Z-scheme SnC/PtSe2 heterostructure with enhanced photocatalytic performance and tunable optoelectronic properties

Recently, direct Z-scheme heterostructures have attracted much attention because of their outstanding electronic properties and excellent photocatalytic performance. In this article, the electronic, optical and photocatalytic properties of SnC/PtSe2 heterojunction are systematically explored via first-principles calculations. Evidence suggests that a Type-II band alignment as well as an indirect bandgap of 1.35 eV can be observed in the SnC/ PtSe2 heterojunction. The combined influence of the built-in electric field from SnC to PtSe2 and the band bending causes a Z-scheme carrier migration mechanism. At biaxial strains of 3%-5%, the band edge positions of the heterojunction are able to cross the redox potential of water. The light absorption coefficient of 4.21 x 105 cm-1 and the energy conversion efficiency of 42.32% demonstrate that the photon energy can be utilized by the heterostructure efficiently. Furthermore, the absorption coefficient in the visible range can be significantly increased under tensile strain. Hence, there are reasons to believe that SnC/PtSe2 heterostructure has tremendous potential for application in the field of photocatalytic water decomposition.