Unique hollow heterostructured CdS/Cd_0.5Zn_0.5S-Mo_1−xW_xS₂: Highly-improved visible-light-driven H₂ generation via synergy of Cd_0.5Zn_0.5S protective shell and defect-rich Mo_1−xW_xS₂ cocatalyst

Photocatalytic water splitting for hydrogen (H₂) production is a green sustainable technology, in which highly-efficient steady photocatalysts are fundamentally required. In this work, unique CdS/Cd_0.5Zn_0.5S-Mo_1−xW_xS₂ photocatalyst constructed by CdS hollow nano-spheres with successively surface-modified Cd_0.5Zn_0.5S shell and defect-rich Mo_1−xW_xS₂ ultrathin nanosheets was reported for the first time. Interestingly, the Cd_0.5Zn_0.5S shell could greatly enhance the photo-stability and reduce the carrier recombination of CdS. Meanwhile, enriching active sites and accelerating charge transfer could be achieved via anchoring defect-rich Mo_1−xW_xS₂ onto CdS/Cd_0.5Zn_0.5S hollow heterostructures. Specifically, the optimized CdS/Cd_0.5Zn_0.5S-Mo_1−xW_xS₂ (6 h Cd_0.5Zn_0.5S-coating, 7 wt.% Mo_1−xW_xS₂, x = 0.5) hybrid delivered an exceptional H₂ generation rate of 215.99 mmol·g⁻¹·h⁻¹, which is approximately 502, 134, and 23 times that of pure CdS, CdS/Cd_0.5Zn_0.5S, and 3 wt.% Pt-loaded CdS/Cd_0.5Zn_0.5S, respectively. Remarkably, a high H₂ evolution reaction (HER) apparent quantum yield (AQY) of 64.81% was obtained under 420-nm irradiation. In addition, the CdS/Cd_0.5Zn_0.5S-Mo_1−xW_xS₂ was also durable for H₂ production under long-term irradiation. This work provides valuable inspirations to rational design and synthesis of efficient and stable hybrid photocatalysts for solar energy conversion.