Z-scheme promoted interfacial charge transfer on Cu/In-porphyrin MOFs/ CdIn2S4 heterostructure for efficient photocatalytic H2 evolution

The rational modulation of charge transfer pathway within heterojunction is essential toward boosting photo- catalytic activity for H2 2 production from water splitting Herein, the bimetallic-modified porphyrin MOFs (CuInPMOFs) crystals have been developed as a substrate for the epitaxial wrapping of CdIn2S4 2 S 4 (CIS) nanosheets via a facile solvothermal process to fabricate novel hierarchical CuIn-PMOFs@CdIn2S4 2 S 4 (CuIn-PMOFs@CIS) heterojunctions. The experimental results, combined with density-functional theory calculations, demonstrated that the CuIn-PMOFs have a more negative conduction band position and the electrons transfer pathway is inclined from CIS to CuIn-PMOFs, which leads to the formation of unique Z-scheme heterojunctions. Profiting from the special "O-In" charge transfer channel, extensive highly active photoinduced electrons areaggregated and depleted in the conduction band of CuIn-PMOFs, contributing to the improvement of H2 2 generation activity. Moreover, the heterojunction model also revealed the minimum Gibbs free energy for H* intermediate adsorption (Delta GH*). Delta G H* ). Concretely, the optimized composite displayed a maximum H2 2 evolution rate of 7527.54 mu mol g -1 h- 1 , which is around 13.12 and 6.63 times higher than that of pure CdIn2S4 2 S 4 and CuIn-PMOFs, respectively. This work aims to suggest that constructing distinctive Z-scheme modulated charge transfer mechanism is an advanced strategy for acquiring highly efficient photocatalysts.