Facile preparation of tungsten oxide doped TiO₂ photocatalysts using liquid phase plasma process for enhanced degradation of diethyl phthalate

In a present study, tungsten oxide was employed to improve the removal efficiency of the parent compound diethyl phthalate as well as to reduce the band gap energy of the original photocatalyst titanium dioxide. The modified photocatalyst was prepared by depositing tungsten oxide onto titanium dioxide through the liquid phase plasma. The decomposition of the parent compound was examined by varying the loading of tungsten oxide in the photocatalyst surface under different light sources, UV and blue light sources. Results showed that the band gap energy in the modified photocatalyst was lower than that of the original photocatalyst, which was attributed to increased loading of tungsten oxide in the modified photocatalyst surface resulted from an increase in the initial precursor concentrations. Tungsten doped in the photocatalyst surface existed in the form of the WO₃, which led to a decrease in the specific surface area for the modified photocatalyst. The degradation performance of the parent compound increased in response to an increase in the amount of tungsten oxide under blue light, but decreased with increasing the loading of tungsten oxide under UV light. Two intermediates observed during the photocatalytic degradation appeared to be involved in the proposed degradation pathway.