SnC/PtS2 heterostructure: A promising direct Z-scheme photocatalyst with tunable electronic optical properties and high solar-to-hydrogen efficiency

Due to their excellent ability of hydrogen evolution, the direct Z-scheme heterostructures are promising to be candidates for next-generation photocatalysts. In this article, the structure, electronic and photocatalytic properties of SnC/PtS2 heterojunction have been investigated by first-principles. The data suggest that SnC/PtS2 heterostructure possesses a Type-Ⅱ band alignment with an indirect bandgap of 1.27 eV which is considerably lower than the bandgap of the SnC (1.79 eV) and PtS2 monolayers (2.67 eV). The built-in electric field directed towards PtS2 from SnC gives rise to a Z-scheme charge transfer mechanism. A maximum bandgap value of 1.32 eV is expressed by the heterojunction at 2% compressive strain. More importantly, the redox potential of water under biaxial strain of −8%–4% is fully satisfied. Light absorption coefficients of 3.81 × 105 cm−1 and the solar-to-hydrogen efficiency of 13.50% proves that the energy of photons is able to be utilized adequately by the heterostructure. Additionally, the absorption peak of the heterojunction at 650 nm is as high as 2.47 × 105 cm−1 under 4% tensile strain. We are therefore convinced that SnC/PtS2 heterojunction have great possibilities for applications in the field of photocatalytic water decomposition.