Enhancing solar-to-hydrogen efficiency with an S-scheme GaTe/PtS van der Waals heterojunction with high light absorption

To tackle the urgent challenges posed by the current energy crisis and environmental concerns, the potential of photocatalytic water splitting has been recognized as a promising solution. In this study, we investigate the structural, electronic, and optical properties of a van der Waals heterojunction (vdwH) formed by combining GaTe and PtS 2 using first-principles calculations. We also examine the Bader charge and solar hydrogen efficiency of this heterojunction to gain insights into its potential for practical applications. The GaTe/PtS 2 heterojunction as a step-scheme (S-scheme) heterojunction has a similar structure to the traditional type-II heterojunction, that is, photo-generated carriers can be automatically separated in space. Analysis of the average charge density difference reveals the presence of a built-in electric field within the heterojunction, which effectively extends the lifetime of carriers. When pH = 0, GaTe/PtS 2 can promote a redox reaction to split water. The high photocatalytic activity of GaTe/PtS 2 is evidenced by its strong light absorption coefficient in the absorption spectrum. Effective modification of the band edge position and optical properties can be achieved through biaxial strain, resulting in increased participation of photons in water splitting. Additionally, the GaTe/PtS 2 heterojunction boasts an impressive solar-to-hydrogen efficiency of 45.88%, and when = 4%, the η STH reaches 52.18%. Thus, our study demonstrates that the GaTe/PtS 2 heterojunction is a promising S-scheme photocatalyst for comprehensive water splitting. In order to solve the current energy and environmental problems, we designed GaTe/PtS 2 van der Waals heterojunction with excellent light absorption and solar-to-hydrogen efficiency, which is an excellent photocatalytic heterojunction.