Transition metal dichalcogenides are interesting candidates as photocatalysts for hydrogen evolution reaction. The MnPSe3/WS2 heterostructure is hence studied here with first principles calculations by exploring its electronic properties under the application of an electric field. It is discovered that the band gap will decrease from the WS2 monolayer to the MnPSe3/WS2 heterostructure with Perdew-Burke-Ernzerhof functional, while increase slightly when electron correlation is involved. The conduction band minimum of the heterostructure is determined by the MnPSe3 layer, while the valence band maximum is contributed by the WS2 layer. The band edges and band gap suggest that the heterostructure will have good photocatalytic properties for water splitting. Moreover, comparing to monolayer WS2, the light absorption in both the ultraviolet and visible regions will be enhanced. When an electric field is present, a linear relation is observed between the electric field and the band gap within specific range, which can thus modulate the photocatalytic performance of this heterostructure.

过渡金属硫属化合物是光催化分解水制氢的可能催化剂。在本工作中我们通过第一性原理计算 研究了一个锰磷硒单层薄膜和二硫化钨单层薄膜所构成的异质结的电子结构性质, 及其对外加电场的 响应。我们发现构建异质结之后, 体系的带隙比单层二硫化钨薄膜有所减小, 其价带和导带的带隙边 缘分别源自锰磷硒单层薄膜和二硫化钨单层薄膜。体系带隙的大小以及带隙边缘的位置表面该异质结 可能是光催化分解水的良好催化材料。与单层二硫化钨薄膜相比较, 所构建的异质结在紫外光和可见 光区域对光的吸收都有所增强。在具有外加电场的情况下, 在特定电场强度范围内电场强度和带隙存 在线性关系, 所以, 施加外加电场可以有效地调节该异质结的带隙和带隙边缘位置, 进而提升其催化 性能。