Co-deposition of Amorphous Carbon and CdS with the Host NiO HMs for Superior Photocatalytic H₂ Production via Water Splitting

Efficient spatial separation of photocarriers is crucial for photocatalyst to achieve superior solar-driven photocatalytic H₂ production via water splitting. In this study, 3D cubic NiO hollow microspheres (HMs) was served as a free-standing supporting matrix for the co-deposition of ultrathin amorphous carbon layer and wurtzite CdS nanoparticles (NPs) to obtain the highly efficient photocatalysis system for H₂ production. The crystal structure, chemical composition, and optical and electric properties of the ternary C@CdS/NiO composite were characterized by various techniques. The results demonstrated that integrated C@CdS/NiO heteroarchitectures with flower-like morphology and double interfacial combinations are successfully constructed through a one-pot microwave heating process. Under simulated solar illumination, the photocatalytic H₂ evolution reaction (HER) efficiency of as-resulting C@CdS/NiO composite reached a remarkable 17.99 mmol∙g^− 1∙h^− 1, which was 5.7 and 163.5 times higher than that of binary CdS/NiO hybrid and single CdS, respectively. The photo-electrochemical measurements disclosed that the double interfacial interactions are beneficial for promoting the photoexcited charge carriers separation in space. Specifically, the ultrathin carbon film played multiple roles for achievement of exceptional photocatalytic activity as follows: (i) having increase of the active sites, (ii) promoting light absorption capacity, (iii) accelerating separation and transport of the photocarriers, and (iv) protecting CdS against photocorrosion. This study provides a facial synergistic modification strategy for the construction of noble-metal-free photocatalysts for efficient solar-to-fuel conversion.