First-principles study on MoSSe/ GaTe van der Waals heterostructures: A promising water-splitting photocatalyst

Photocatalytic water splitting using semiconductor electrocatalysts in photoelectrochemical cells is an appealing approach to converting sunlight and water into clean and renewable hydrogen fuel. MoSSe/GaTe der Waals heterojunctions has recently been suggested as a promising photocatalyst for water splitting. Depending on the stacking mode, the two type MoSSe/GaTe heterojunctions have moderate band gaps of 1.081 eV and 1.307 eV, significant visible absorption coefficients, and band-edge positions spanning the redox potential of water. Bader charge and differential charge density analyses show that the GaTe layer loses electrons and the MoSSe monolayer gains electrons, resulting in a built-in electric field pointing from the GaTe layer to the MoSSe layer. Moreover, the Gibbs free energy diagram indicates that solar energy can effectively drive water splitting on MoSSe/GaTe junction. The influence of the bi-axial strain and pH value of water are discussed. Therefore, the MoSSe/GaTe heterostructures are promising for applications in photocatalytic water decomposition.