Broad-spectrum responsive MOF-derived Z-scheme heterojunction for dual-functional photocatalysis of cooperative hydrogen evolution and benzylamine oxidation coupling

Abstract

The construction of synchronous cooperative redox dual-functional photocatalysts is an efficient strategy for enhancing catalytic ability. It not only reduces organic pollution and waste of photogenerated holes from sacrificial electron donors but also integrates with biomass conversion for the generation of valuable chemicals. Herein, broad-spectrum responsive dual-functional NiS/MnCdS photocatalysts are developed by constructing Z-scheme heterojunction for efficient hydrogen evolution and synergistic benzylamine oxidation coupling. The NS/MCS-100 obtained exhibits remarkable photocatalytic performance under visible light, with a hydrogen evolution rate of 1.61 mmol·h−1·g−1, benzylamine conversion rate exceeding 90 %, and an approximate selectivity towards N-benzylbenzaldimine of 99 %, which is seven times higher than that of pure MnCdS. Subsequently, experimental characterizations and DFT calculations confirm that the construction of Z-scheme heterojunctions maintains a high redox potential for catalysts, enhancing the redox ability and thereby improving photocatalytic efficiency to achieve coordinated dual-function catalysis. In addition, the advantages of MOF template-derived strategy in structure and defect engineering for effective separation of photogenerated charge carriers have enhanced the photocatalytic performance of this composite catalyst. This work not only reveals a strategy to construct Z-scheme heterojunctions with broad-spectrum response without any sacrificing agents to enhance photocatalytic performance but also demonstrates its significant potential for the application of other highly efficient synergistic dual-functional photocatalytic reactions.