Construction of 3D/3D heterojunction between new noble metal free ZnIn2S4 and non-inert metal NiMoO4 for enhanced hydrogen evolution performance under visible light

Abstract

Promoting the separation of electron and hole plays an important role in photocatalytic hydrogen production. However, single semiconductor materials cannot fully realize their potential due to the rapid recombination of photogenerated carriers. Therefore, in this experiment, a new photocatalyst ZnIn2S4/NiMoO4 was prepared by using an electrostatic self-assembly method, which greatly improved the electron-hole recombination phenomenon. After 5 h reaction under visible light irradiation, ZIS/NMO-3 composite catalyst prepared in ethanol showed the best photocatalytic activity, and the hydrogen evolution capacity reached 173.09 μmol. The hydrogen evolution capacity of ZIS/NMO-3 was 2.47 and 25.83 times that of short rod-like NiMoO4 and microflower-like spherical ZnIn2S4, respectively. Through some physical characterization and electrochemical experiments, it can be seen that NiMoO4 and ZnIn2S4 have good composability. Meanwhile, the composite catalyst ZnIn2S4/NiMoO4-3 has high current response characteristics. It can be seen from the fluorescence emission spectra that the composite catalyst presents the lowest peak value, which indicates that ZIS/NMO-3 can effectively inhibit the recombination of photogenerated electrons and holes. When ZnIn2S4 is loaded on NiMoO4, the separation of photogenerated carrier will be accelerated due to the formation of heterojunction, thus improving the photocatalytic activity. At the same time, the large specific surface area will also provide more abundant active sites for the composite catalyst, which provides a good condition for photocatalytic hydrogen production. This work provides an efficient, uncomplicated and feasible method for the synthesis of ZIS/NMO-3 composite catalyst with excellent properties.