Visible-light-driven two dimensional metal-organic framework modified manganese cadmium sulfide for efficient photocatalytic hydrogen evolution

The morphology modification and the construction of heterojunction of the photocatalyst are considered as the main means to significantly improve the performance of photocatalytic hydrogen evolution. In this study, Mn0.2Cd0.8S nanorods are successfully assembled on the surface of Ni-MOF-74 with flake morphology. Specifically, the Ni-S bond is constructed between Ni-MOF-74 and Mn0.2Cd0.8S, which provides a unique transfer channel for photo-induced carriers. Meanwhile, the electrons in the conduction band of Mn0.2Cd0.8S can be injected into the conduction band of Ni-MOF-74 quickly due to the potential energy difference between the two. This shows that the recombination of photogenerated carriers in Mn0.2Cd0.8S can be greatly inhibited. Fluorescence spectroscopy and electrochemical characterization reveal that the composite catalyst has the longest carrier lifetime, the fastest charge transfer rate and the lowest overpotential compared with the Mn0.2Cd0.8S and Ni-MOF-74. The optimal hydrogen production rate of the composite can reach 7.104 mmol g−1h−1, which is 6.96 times that of Mn0.2Cd0.8S. This work provides a novel strategy for the modification of MnCdS-based photocatalysts by metal–organic framework materials.