Tandem Structures Semiconductors Based on TiO₂_SnO₂ and ZnO_SnO₂ for Photocatalytic Organic Pollutant Removal

The photocatalyst materials correlation with the radiation scenario and pollutant molecules can have a significant influence on the overall photocatalytic efficiency. This work aims to outline the significance of optimizing the components mass ratio into a tandem structure in order to increase the photocatalytic activity toward pollutant removal. ZnO_SnO₂ and TiO₂_SnO₂ tandem structures were obtained by the doctor blade technique using different mass ratios between the components. The samples contain metal oxides with crystalline structures and the morphology is influenced by the main component. The photocatalytic activity was tested using three radiation scenarios (UV, UV-Vis, and Vis) and two pollutant molecules (tartrazine and acetamiprid). The results indicate that the photocatalytic activity of the tandem structures is influenced by the radiation wavelength and pollutant molecule. The TiO₂_SnO₂ exhibit 90% photocatalytic efficiency under UV radiation in the presence of tartrazine, while ZnO_SnO₂ exhibit 73% photocatalytic efficiency in the same experimental conditions. The kinetic evaluation indicate that ZnO_SnO₂ (2:1) have a higher reaction rate comparing with TiO₂_SnO₂ (1:2) under UV radiation in the presence of acetamiprid.