Synthesis and characterisation of W–Bi–S-tridoped TiO 2 nanoparticles with enhanced photocatalytic activity

In the present work, W–Bi–S-tridoped TiO₂ nanoparticles were synthesised by a simple sol–gel method. The structure and morphology of as-prepared W–Bi–S-tridoped TiO₂ were characterised by using X-ray powder diffraction, transmission electron microscopy, scanning electron microscopy and UV–Vis diffuse reflectance spectrum. It was found that the W–Bi–S-tridoped TiO₂ nanoparticles were well crystallised with a small size distribution. The absorption edge of TiO₂ was extended into visible-light region obviously after being doped with W, Bi and S. The photocatalytic degradation of methylene blue was used as a probe reaction to evaluate the efficiency of W, Bi and S doping. The W–Bi–S-tridoped TiO₂ exhibited the best photocatalytic activity, compared with TiO₂, S-TiO₂, W–S–TiO₂ and Bi–S–TiO₂. The mechanism that enhanced photocatalytic activity might be attributed to the synergistic effect of W, Bi and S.