Solar-Light-Driven Photocatalytic Water Splitting Using CuS/ZnS Type II Heterojunction: A Route to Green Hydrogen Production

Abstract

The efficacy of photocatalysts for green hydrogen (H2) production by solar-driven photocatalytic water splitting is still severely limited by ineffective charge separation, quick charge carrier recombination and low structural stability. In this study, a simple, low-temperature hydrothermal synthesis of CuS and ZnS (CZS) was used to rationally design a heterojunction photocatalyst, providing a simple and scalable method for improved photocatalytic performance. After 12 hours of continuous 1-sun irradiation, the CZS nanocomposite showed a remarkable cumulative H2 production of 12,145 μmol g⁻¹ which is more activity than the pristine CuS and ZnS. Additionally, the CZS heterojunction nanostructure has ~0.16% of solar to hydrogen efficiency (STH). Extensive structural and spectroscopic investigations, including as XRD, TEM, UV-Vis absorption spectroscopy and XPS revealed the CZS confirms the formation of structured system with strong interfacial interactions. The proposed composite has a unique physicochemical characteristics and synergistic interactions, supporting its increased photocatalytic activity. Improved light absorption and effective interfacial charge separation within the composite are the responsible for increased photocatalytic performance. This work highlights the efficient and scalable solutions for solar-driven H2 production with earth-abundant sulphide materials for a viability hetero-structured system. This type of system with synergistic characteristics paves the path for a sustainable world towards decarbonization.