Preparation and characterization of tungsten-loaded titanium dioxide photocatalyst for enhanced dye degradation

Tungsten-loaded TiO2 photocatalyst has been successfully prepared and characterized. TEM analysis
showed that the photocatalysts were nanosize with the tungsten species forming layers of coverage
on the surface of TiO2, but not in clustered form. This was confirmed by XRD and FT-Raman analyses
where tungsten species were well dispersed at lower loading (<6.5 mol%), but were in crystalline WO3
at higher loadings (>12 mol%). In addition, loading with tungsten could stabilize the anatase phase from
transforming into inactive rutile phase and did not shift the optical absorption to the visible region as
shown by DRUV–vis analysis. PZC value of TiO2 was found at 6.4, but the presence of tungsten at 6.5 mol%
WO3, decreased the PZC value to 3. Tungsten-loaded TiO2 was superior to unmodified TiO2 with 2-fold
increase in degradation rate of methylene blue, and equally effective for the degradation of different class
of dyes such as methyl violet and methyl orange at 1 mol% WO3 loading.