Highly Enhanced Photocatalytic Properties of Tin Selenide Nanopowders by Microstructure Modulation

Wide-band-gap semiconductor photocatalytic materials are limited in their application because they can only absorb ultraviolet light, while tin selenide (SnSe) with a narrow band gap is a promising photocatalyst that responds to visible and near-infrared light. Herein, pure SnSe nanopowders with a narrow band gap were synthesized by regulating the reaction temperature in the process of hydrothermal reaction. The powder samples showed self-assembled micrometer flowers of nanosheets and nanorods, which facilitated the degradation of contaminant dyes by increasing the length of the light path. The properties of the photocatalytic degradation of rhodamine B (RhB) by the SnSe powders synthesized at a temperature gradient of 20 °C from 80 to 120 °C were investigated. The results show that the degradation rate of RhB reached 98.2% in 60 min by pure SnSe powder prepared at 100 °C (SnSe-100), which was attributed to the "light trapping effect" created by its unique and intact micron-flower structure. In addition, degradation experiments were also carried out on common organic dyes, in which the decomposition rate of methylene blue reached 92.86%. This can be applied to the treatment of water pollution and provides a quick solution.