Construction of S-Scheme heterojunction Ni₁₁(HPO₃)₈(OH)₆/CdS photocatalysts with open framework surface for enhanced...

The emerging S-scheme heterojunction shows a particular superiority in enhancing the efficiency of charge separation in photocatalyst. Herein, a Ni₁₁(HPO₃)₈(OH)₆/CdS heterojunctions (NiPO/CdS) are constructed for the first time by loading open framework structure NiPO on the surface of CdS nanoparticles (CdS NPs). The built-in electric field generated at the interface promotes the directional migration of photogenerated electrons from NiPO to CdS. This S-scheme pathway achieves a strong redox capacity and efficient carrier separation. More importantly, the unique triangular and hexagonal channels of NiPO facilitate the exposure of CdS active sites for proton adsorption, H₂ production and escape. The hydrogen evolution rate of NiPO/CdS is 39 mmol g^-1 h^-1 under visible light irradiation, which is 6.5 times higher than that of pure CdS. The NiPO/CdS heterojunction also exhibits remarkable long-term stability. This study provides a new strategy for the ingenious design of S-scheme photocatalysts with excellent photocatalytic performance.