ZIF-67-derived ZnIn2S4/NiCoP Z-scheme heterojunctions for enhanced visible-light-driven photocatalytic hydrogen production

Z-scheme photocatalytic heterojunction is considered as an effective strategy to promote the photogenerated electron-hole separation for improving the efficiency of photocatalytic hydrogen precipitation from splitting water significantly. Herein, a novel Z-scheme 2D-ZnIn2S4/NiCoP heterojunction is successfully prepared by coupling NiCoP derived from ZIF-67 through phosphating treatment with 2D-ZnIn2S4 lamellae via a facile hydrothermal method. The Z-scheme heterostructure of ZnIn2S4/NiCoP could suppress the recombination-rate of photogenerated electron-hole pairs and enhance the visible-light-driven photocatalytic hydrogen production. As a result, the hydrogen production rate of 2D-ZnIn2S4/NiCoP (10 wt% ZnIn2S4) increase to 5098.12 mu mol g(-1) h(-1) significantly with an apparent quantum yield (AQY) of 5.24% at 420 nm, which is 3.07 times than that of bare ZnIn2S4. The enhancement of photocatalytic performance is attributed to the following issues: 2D-ZnIn2S4 could avoid the agglomeration of tiny ZnIn2S4, exposing more active sites and shortening the transmission distance of photogenerated carries; the formation of Z-scheme heterostructure could promote the separation of photogenerated electron-hole pairs; the unique hollow structure of NiCoP derived from ZIF-67 could inhibit the recombination of the photogenerated electron-hole. Overall, this work could provide a new idea for designing and preparing of visible-light-driven photocatalysts with high efficiency for photocatalytic hydrogen production.

Automated summary

This study successfully prepared a novel Z-scheme 2D-ZnIn2S4/NiCoP heterojunction by coupling NiCoP derived from ZIF-67 with 2D-ZnIn2S4 lamellae. The Z-scheme structure of ZnIn2S4/NiCoP could suppress the recombination of photogenerated electron-hole pairs and enhance the photocatalytic hydrogen production. The enhanced performance is attributed to the avoidance of agglomeration, increased active sites, shortened transmission distance, and inhibition of recombination.