Unleashing the solar-driven overall water-splitting potential for green ZnIn2S4

Sustainable hydrogen production through the photoconversion of water represents one of the leading-edge approaches for generating green energy to achieve carbon neutrality. However, most of the outstanding photocatalytic systems capable of effectively splitting pure water rely on expensive noble-metal co-catalysts. In this work, we incorporate low-cost Ni-hybrid co-catalysts onto sulfur-vacant hollow green ZnIn₂S₄ (NNOgZIS) through the co-deposition of Ni and NiO_x onto the reductive and oxidative sites from self-generative electron-hole pairs. NNOgZIS demonstrates exceptional solar-driven pure water splitting and achieves a solar-to-hydrogen conversion efficiency exceeding that of most noble-metal-loaded single-sulfide-based systems. Additionally, it facilitates the photo-oxidative production of high-energy hydrogen peroxide. The diverse applications of NNOgZIS are positively presented through simulated seawater splitting and coupled oxidative reactions as well as a demonstration of workability in a film-based system. This study presents the potential of integrating low-cost metals into augmenting photocatalytic efficiency, establishing a foundation for cost-effective and sustainable photocatalytic-fuel-forming innovation.