Interfacial construction of SnS₂/Zn_0.2Cd_0.8S nanopolyhedron heterojunctions for enhanced photocatalytic hydrogen...

ZnCdS, a metal chalcogenide solid solution, has attracted significant attention. However, two primary challenges hinder its widespread application in photocatalytic hydrogen evolution: the rapid recombination rate of photogenerated carriers and susceptibility to photo-oxidation in the aqueous environments. In this article, a facile hydrothermal route was employed for the first time to uniformly assemble SnS₂ nanoparticles onto the surface of Zn_0.2Cd_0.8S (ZCS) nanopolyhedra. The intimate contact of two materials resulted in the formation of heterojunctions. By adjusting the content of SnS₂, the hydrogen evolution reaction (HER) performance was optimized to reach up to 12170 μmol/gh, which is 1.9 times of the pristine ZCS. Notably, the photocatalyst demonstrated remarkable stability with an apparent quantum yield (AQY) of 15.5% at 420 nm. The enhanced photocatalytic performance can be attributed to the following factors: (i) The heterojunction composite, with larger surface area and more micropores, provides additional active sites and exhibits high photocatalytic activity; (ii) The internal electric field accelerates the separation of photogenerated carriers and reduces the recombination rate of electron-hole pairs; (iii) The photogenerated holes can be quickly transferred to the valence band of SnS₂ and react with triethanolamine, thereby significantly reducing the photo-oxidation of ZCS. This work not only proposed a feasible route to improve the photocatalytic activity of ZCS, but also provided insights into the role of heterojunctions and the reaction mechanism.