Surface engineering modulation and optimization of S-vacancy ZnCdS combined with NiMnS for efficient photocatalytic hydrogen evolution

The built-in electric field at the interface plays a crucial role in enhancing photocatalytic hydrogen production by improving the separation efficiency of photoinduced charge carriers. In this study, S-vacancies were introduced into ZnCdS, and metal-like NiMnS was combined with ZnCdS containing S-vacancies to form ohmic junctions for photocatalytic hydrogen evolution. The optimized Vs-ZnCdS/NiMnS photocatalyst achieves a hydrogen production rate of 1964.8 µmol g⁻¹ h⁻¹, representing a 2.58 times enhancement over Vs-ZnCdS alone. A thorough examination has been undertaken, the results of which indicate that the significant Fermi level offset between NiMnS and Vs-ZnCdS gives rise to a robust built-in electric field across the heterointerface. This interfacial electric field facilitates efficient dissociation of electron-hole pairs, consequently improving charge carrier mobility. Additionally, the introduction of S-vacancies provides additional electron transport channels, further accelerating interfacial charge migration. Consequently, the highly reducing electrons in NiMnS are retained and utilised for the hydrogen generation, resulting in significantly improved photocatalytic activity. This investigation delivers theoretical insights and experimentally validated methodologies for boosting H₂ evolution performance through rational interface regulation.