Atomically dispersed Ru on defective CdS for photocatalytic solar fuel production coupled with hydrazine degradation

Photocatalytic solar fuel production offers a sustainable approach for generating renewable feedstocks. However, this promising strategy is often hindered by the sluggish reaction kinetics and undesired CO₂ emission. In this study, we develop a CdS-Ru photocatalyst through the introduction of sulfur vacancy and atomically dispersed Ru sites into defective CdS. This design promotes directional charge transfer and forms highly active redox centers. Further leveraging the distinctive kinetic and thermodynamic features of hydrazine oxidation as a chemical regulation strategy, we establish a dual-functional paradigm that couples solar fuel production with hydrazine degradation. The CdS-Ru photocatalyst achieves hydrogen evolution and methanol production rates of 212.7 mmol g^-1 h^-1 and 1.4 mmol g^-1 h^-1, respectively. It shows a substantial improvement over pristine CdS, and outperforms the systems employing conventional sacrificial reagents, such as triethanolamine or sulfides. Notably, this process yields no carbon-based byproducts (e.g., CO, CO₂, and formaldehyde), ensuring a cleaner fuel production pathway. Comprehensive experimental analyses and theoretical simulations are conducted to elucidate the structural and electronic properties of the CdS-Ru catalyst, as well as the working mechanism of redox coupling, providing new insights for constructing dual-functional photocatalysts to tackle environmental and energy crises.