Accelerated charge transfer of Cd0.5Zn0.5S@ZnS core–shell nano-spheres via decoration of Ni2P and g-C3N4 toward efficient visible-light-driven H2 production

Abstract

Development of noble-metal-free photocatalysts for efficient H₂ production from sunlight-driven water-splitting has aroused great interest in recent years. Herein, unique Cd_0.5Zn_0.5S@ZnS core–shell nano-spheres decorated with Ni₂P and g-C₃N₄ cocatalysts were prepared for the first time, and they are highly active and stable toward the visible-light-driven (λ > 420 nm) H₂ evolution reaction (HER). Noticeably, the optimized Cd_0.5Zn_0.5S@ZnS-Ni₂P/g-C₃N₄ with 50 wt% ZnS, 3 wt% Ni₂P, and 8 wt% g-C₃N₄ (CZ_0.5S@50ZS-3N/8CN) exhibits a superior HER activity of 55.43 mmol·g⁻¹·h⁻¹, approximately 25 and 18 times higher than those of CZ_0.5S@50ZS and Pt-decorated CZ_0.5S@50ZS (CZ_0.5S@50ZS-Pt), respectively. Meanwhile, the corresponding apparent quantum yield (AQY) at 420 nm is as high as 21%. It is revealed that the protective ZnS shell on the CZ_0.5S core enhances the photo-stability of the hybrid significantly. Moreover, the synergistic effect of the Ni₂P and g-C₃N₄ cocatalysts leads to the effective transfer and separation of charge carriers. The results presented in this work may pave the way for the ingenious design and fabrication of highly active nano-structures for sufficient solar utilization.