S-SCHEME ZnO-WO3 HETEROJUNCTION FOR BOOSTING SYNTHETIC DYE PHOTODEGRADATION IN AQUEOUS SOLUTIONS

Tóm tắt

In this study, a ZnO-WO3 heterojunction was synthesized from Zn2+ and W6+ precursors using sol-gel and calcination methods. The structural, chemical, and optical properties of the resulting materials were characterized by a range of techniques including XRD, UV-Vis, SEM/TEM, EDX, FT-IR, and BET.
The synthesized ZnO-WO3 materials were subsequently tested for their photocatalytic activity in the degradation of synthetic dyes under visible light. The effects of varying W/Zn molar ratios and contaminant concentrations on photocatalytic performance were investigated. The formation of the ZnO-WO3 heterojunction reduced the band gap to 2.84 eV, enabling efficient photocatalysis under visible light. The ZnO-WO3 heterojunction exhibited 2-4 times higher photodegradation efficiency for methylene blue (MB) compared to pure ZnO and WO3. This enhanced performance was attributed to the formation of an S-scheme heterojunction, which effectively suppressed charge carrier recombination. The MB degradation process followed pseudo-first-order kinetics, and the ZnO-WO3 photocatalyst demonstrated excellent stability and reusability throughout multiple cycle