Recognizing the appropriateness of band edge positions of SiH/HfS₂ based heterostructure for water splitting

This work describes a novel kind of material formed by layering a SiH monolayer on top of a HfS₂ monolayer in three distinct stacking patterns using first principles characterization. The CASTEP program enabled an examination of the electronic band structures, optical response, photocatalytic features, and durability of SiH/HfS₂-based heterostructures. Using the HSE06 approach, we discovered a stable SiH/HfS₂ heterostructure with an indirect bandgap of 1.589 eV and type-II band alignment. The work function estimated for aa stacking is 4.65 eV, indicating the process of building a heterostructure between SiH and HfS₂, as well as enhancing electronic transitions between two layers. These transitions continue until the Fermi level achieves dynamic equilibrium, at which point an electric field is generated across the two layers, facilitating the dissociation of electron hole pairs. The electronic bandgap of SiH/HfS₂ reduces linearly as biaxial strain rises, reaching its minimum value at ＋6% strain. In turn, modifying optoelectronic properties for SiH/HfS₂ heterostructure show a rising trend in both the visible and ultraviolet spectra, with the violet portions showing the most notable peak. Furthermore, the findings reveal that the SiH/HfS₂ vdW-HS has suitable water splitting band edge positions for HER and OER reactions and 17.22% hydrogen generation efficiency as detected using HER, confirming its potential usefulness as a photocatalyst for water splitting.