Visible–light–driven photocatalyst for solar–to–hydrogen efficiency via a Type–II SGaInS/GaGePS van der Waals heterostructure

Developing efficient, cost–effective visible–light–driven photocatalysts for solar hydrogen production via water splitting presents a promising solution to address growing energy demands. We present a comprehensive first–principles investigation of SGaInS/GaGePS heterostructure as a promising visible–light–driven photocatalyst. Our results reveal that SGaInS/GaGePS forms a type–II van der Waals heterostructure with an optimal bandgap of 2.38 eV, facilitating effective electron–hole separation. The heterostructure shows good thermal and dynamic stability. The calculated band edge positions align well with the redox potentials required for water splitting, enabling the hydrogen and oxygen evolution reactions to proceed independently on the SGaInS and GaGePS monolayers, respectively. Charge density difference and work function analyses further demonstrate significant interfacial charge transfer, forming an intrinsic electric field at the heterostructure interface. Additionally, the SGaInS/GaGePS van der Waals heterostructure exhibits enhanced visible light absorption compared to its constituent monolayers, underscoring its potential for solar energy conversion. These findings provide a theoretical foundation for the experimental design of novel type–II van der Waals heterostructures for photocatalytic water splitting, paving the way for advancements in sustainable energy technologies.