Effects of Synthesis Method and Metal Oxide Promoters on Photocatalytic Activity of Titania-Silica in Degradation of Dye Pollutant

In this study, the performance of titania-silica catalysts with different loadings of titania was investigated in the photocatalytic degradation of Rhodamine B (RhB) dye pollutants under ultraviolet radiation. Moreover, two synthesis methods, i.e., dry and wet impregnation, were compared. It was shown that photocatalytic degradation of RhB was higher on the catalyst prepared via wet impregnation. To further improve the photocatalytic activity of the titania-silica, oxides of different metals including tungsten, bismuth, cerium, vanadium, iron, copper, silver, nickel, and zinc were used as promoters. The materials were characterized by Fourier-Transform InfraRed (FT-IR spectroscopy), X-Ray Diffraction (XRD), and N2adsorption–desorption to characterize the catalysts and find their structure-function relationships. It was found that the photocatalytic degradation of RhB over the titania-silica catalyst synthesized by wet impregnation containing 3 wt.% of tungsten oxide could achieve 98% after 240 min at reaction conditions of pH=6, initial RhB concentration=10 mg/L, catalyst dosage= 1 g/L, and temperature of dye solution= 25 ℃.