Nanoparticulate Double-Heterojunction Photocatalysts Comprising TiO2(Anatase)/WO3/TO2(Rutile) with Enhanced Photocatalytic Activity toward the Degradation of Methyl Orange under Near-Ultraviolet and Visible Light

Nanoparticulate double-heterojunction photocatalysts comprising TiO2(Anatase)/WO3/TO2(Rutile) were produced by a sol-gel method. The resulting photocatalysts exhibit clear synergistic effects when tested toward the degradation of methyl orange under both UV and visible light. Kinetic studies indicate that the degradation rate on the best double-heterojunction photocatalyst (10 wt % WO3-TiO2) depends mainly on the amount of dye concentration, contrary to pure oxides in which the degradation rate is limited by diffusion-controlled processes. The synergistic effects were confirmed through systematic and careful studies including holes and OH radical formation, X-ray diffraction, electron microscopy, elemental analysis, UV-vis diffuse reflectance spectroscopy, and surface area analysis. Our results indicate that the successful formation of a double heterojunction in the TiO2(Anatase)/WO3/TO2(Rutile) system leads to enhanced photoactivity when compared to individual oxides and commercial TiO2 P25.

Automated summary

Nanoparticulate double-heterojunction photocatalysts consisting of TiO2(Anatase)/WO3/TO2(Rutile) were synthesized via a sol-gel method, exhibiting synergistic effects in the degradation of methyl orange under both UV and visible light. The degradation rate of the best catalyst was found to depend mainly on dye concentration, as opposed to diffusion-controlled processes seen in pure oxides. The successful formation of a double heterojunction in the system led to enhanced photoactivity compared to individual oxides and commercial TiO2 P25, confirmed through various analyses.