Effect of calcination temperature on one-step in situ preparation of SnSe/SnO2 heterojunction and its photocatalytic performance

Abstract

This study aims to synthesize micro-nano SnSe/SnO2 heterojunction in situ in one step. The relationship between the temperature and structure, and the photocatalytic properties of the composite is explored. The structure, morphology, and optical properties of the catalyst are characterized. The photocatalytic activity of the developed composite is evaluated by testing the catalyst on methylene blue (MB) solution. The results reveal that the selenidation temperature considerably impacts the final structure of the developed materials. Sn3O4 is selenified at 700 °C, essentially forming a flower-like structure through self-assembly of nanoplates with a length and thickness of approximately 600 nm and 300 nm, respectively. The phase composition of selenide products at 700 °C is primarily SnSe and SnO2. SnSe/SnO2 heterojunction is formed simultaneously in situ, thus improving the charge transfer ability of the composite. Hence, SS-700 °C exhibits the best photocatalytic response in the tested materials. Additionally, the photocatalytic degradation of MB by SnSe/SnO2 heterojunction composites is highly dependent on the generation of hydroxyl radicals.