Metal-organic framework-derived ZnxCd1-xS/ZnxCd1-x-MOF heterostructures promoting charge separation for photocatalytic hydrogen evolution

Severe charge recombination is a bottleneck for efficient photocatalytic hydrogen production. Herein, ZnxCd1-xS/ZnxCd1-x-MOF heterostructures with enhanced photocatalytic hydrogen evolution activity are synthesized by a two-step solvothermal process based on a metalorganic framework (MOF) template method. By carefully tuning the composition and the reaction temperatures, the obtained Zn0.2Cd0.8S/Zn0.2Cd0.8-MOF heterojunction can continuously generate hydrogen for 25 h, with an optimized hydrogen production rate of 13.3 mmol g-1h-1. An impressive apparent quantum yield of 24.1 % at 420 nm monochromatic light is achieved. Zn0.2Cd0.8S nanoparticles are embedded in the Zn0.2Cd0.8-MOF skeleton during the solvothermal process, resulting in excellent distribution and interfacial contact in the obtained heterojunction. Such a heterostructure not only promotes charge separation, but also alleviates photocorrosion. The proof-of-concept demonstrated in this work provides an alternative way for the design of high-performance metal sulfide-based photocatalysts for efficient solar hydrogen production.