Efficient spatial separation of charge carriers over CoS1+x cocatalyst modified MIL-88B (Fe)/ZnIn2S4 S-scheme heterojunctions for photoredox dual reaction and insight into the charge-transfer mechanism

Abstract

The key to achieve an efficient cooperative photoredox reaction system is to elaborately construct high-efficiency multifunctional photocatalysts with the maximum carrier utilization. Herein, a well-design S-scheme MIL-88B (Fe)/ZIS heterojunction modified with amorphous CoS1+x cocatalyst (CMZIS) was firstly successfully constructed. The CMZIS heterojunctions show a high H2 evolution rate of 3164.9 μmol g−1h−1 coupling with a benzaldehyde generation rate of 3417.8 μmol g−1h−1, which are 7.9 and 8.1 times higher than those of pure ZIS. The excellent performance of CMZIS heterojunctions benefits from the synergistic effect of S-Scheme heterojunction and CoS1+x cocatalysts. This synergy realized the directional transfer and spatial separation of photogenerated carriers in CMZIS, thus inhibiting charge recombination and and maximizing the redox ability of charge carriers. Moreover, CoS1+x cocatalyst offer more active sites and further enhance the H2 evolution efficiency. This work will offer fresh insights to the construction and mechanism study of advanced multifunctional photocatalysts for the highly efficient cooperative photoredox reaction system.