First-principles prediction of a novel 2D InAs/PtSe2 direct Z-scheme van der Waals heterojunction for overall water-splitting

The construction of heterojunctions presents a promising strategy for developing efficient photocatalysts for hydrogen production via water decomposition. In this paper, a new type of two-dimensional (2D) InAs/PtSe₂ direct Z-scheme van der Walls (vdWs) heterojunction is designed. Utilizing the first-principles density functional theory (DFT), we systematically investigate its geometric structure, electronic, optical and photocatalytic characteristics. Our findings indicate that the heterojunction exhibits a type-II band alignment, coupled with an intrinsic electric field oriented from InAs to PtSe₂ at the interface. The synergistic effect of the electric field and energy band bending effectively promotes separation of photogenerated carriers. Moreover, the InAs/PtSe₂ heterojunction demonstrates superior photocatalytic water-splitting performance, enabling spontaneous hydrogen evolution in both acidic and neutral environments. These results position the 2D InAs/PtSe₂ direct Z-scheme vdWs heterojunction as a highly promising material for efficient solar-driven water-splitting applications.