Boosting Visible-Light Photocatalytic Redox Reaction by Charge Separation in SnO₂ /ZnSe(N₂ H₄ )_0.5 Heterojunction...

In this work, environmentally friendly photocatalysts with attractive catalytic properties are reported that have been prepared by introducing SnO₂ quantum dots (QDs) directly onto ZnSe(N₂ H₄ )_0.5 substrates to induce advantageous charge separation. The SnO₂ /ZnSe(N₂ H₄ )_0.5 nanocomposites could be easily synthesized through a one-pot hydrothermal process. Owing to the absence of capping ligands, the attached SnO₂ QDs displayed superior photocatalytic properties, generating many exposed reactive surfaces. Moreover, the addition of a specified amount of SnO₂ boosted the visible-light photocatalytic activity; however, the presence of excess SnO₂ QDs in the substrate resulted in aggregation and deteriorated the performance. The spectroscopic data revealed that the SnO₂ QDs act as a photocatalytic mediator and enhance the charge separation within the type II band alignment system of the SnO₂ /ZnSe(N₂ H₄ )_0.5 heterojunction photocatalysts. The separated charges in the heterojunction nanocomposites promote radical generation and react with pollutants, resulting in enhanced photocatalytic performance.