Hierarchical Zn1-xCdxS microclusters with superior visible-light-driven photocatalytic hydrogen generation performance

Hierarchical Zn x Cd 1-x S (x = 1, 0.85, 0.74, 0.64, 0.46 and 0.36) microclusters were successfully prepared by a secondary growth strategy using ethanol as solvent under solvothermal condition. Cluster-like ZIF-8 crystals derived from crystalline hierarchical zinc carbonate, CdCl 2 inorganic salt and thiourea were used as the starting materials at stoichiometric ratios. The as-prepared hierarchical hierarchical Zn 0.64 Cd 0.36 S material exhibits excellent water splitting performance with a maximum H 2 generation rate of 815 μmol g −1  h −1 under visible-light irradiation in the presence of sacrificial agent of 0.25 M Na 2 S and 0.35 M Na 2 SO 3 . This hydrogen generation efficiency is about 23 times higher than that of pure CdS (34.7 μmol g −1  h −1 ) and 14 times higher than Zn 0.64 Cd 0.36 S reference material (56.4 μmol g −1  h −1 ) prepared by one-pot hydrothermal method . The hierarchical Zn 0.64 Cd 0.36 S material exhibits a synergetic effect as a photocatalyst to enhance hydrogen generation and the corresponding photocatalytic mechanism is discussed in detail. This work demonstrates a feasible morphology preservation strategy to prepare novel hierarchical composites with specific chemical composition, high surface area, and abundant active sites, characterized by a rapid diffusion and separation of photogenerated charge carriers proving a visible-light driven photocatalytic hydrogen generation.