Novel 0D/2D ZnSe/SnSe heterojunction photocatalysts exhibiting enhanced photocatalytic and photoelectrochemical activities

Abstract

The narrow band gap and low internal resistance of metal selenides make them a promising new type of photocatalysts. Studies have shown that catalysts performance can be greatly improved by a heterojunction constructed by two selenides. We designed a novel ZnSe/SnSe 0D/2D heterostructure by uniformly loading ZnSe nanoparticles on the surface of SnSe nanosheets. Results show that the heterojunction photocatalyst has enhanced photoelectrochemical performance and higher photocatalytic degradation rate. The heterojunction catalyst with a ZnSe loading ratio of 2.5% has the best performance: compared with SnSe, the photocatalytic activity and photoelectrochemical properties of the composite improved by 278% and 164%, respectively. Further analysis showed that the internal resistance of the synthesized catalyst was greatly reduced and the carrier efficiency was largely improved. Further mechanistic analysis shows that in the ZnSe/SnSe heterojunction, photo-induced electrons in the conduction band of ZnSe will flow into that of SnSe to improve the carriers’ separation efficiency. The holes induced in the valence band of ZnSe can produce OH•, which acts as active species and achieves dye degradation. This experiment confirmed that SnSe/ZnSe photocatalyst heterojunction is an effective strategy and plays an important role in the development of efficient photocatalysis technology.