Photodegradation of methylene blue in the visible spectrum: An efficient W6+ ion doped anatase titania photocatalyst via a solvothermal method

•Tungsten doped anatase titania with high photocatalytic efficiency was prepared by a facile, one step solvothermal method.•Valence state of tungsten ion as W6+ was confirmed by advanced analysis of X-ray photoelectron spectroscopy.•Incorporation of W6+ ions into titania changed the bulk and surface properties of anatase titania.•Degradation mechanism of methylene blue in water was discussed in detail.

Solvothermal prepared tungsten (VI) doped titania were evaluated as photocatalysts for methylene blue (MB) degradation under the visible spectrum. Incorporation of hexavalent tungsten alters both the surface and bulk properties. Addition of tungsten into the titania lattice changes the lattice parameter, morphology and photocatalytic performance. X-ray photoelectron spectroscopy and x-ray diffraction suggested that W6+ does not change the chemical environment of Ti4+ but contracts the lattice of titania. By adding 5 wt% tungsten, the resulting sample shows high surface area (130.4 m2/g), a contracted lattice and high efficiency for photodegradation (120 min bleaching with a remaining concentration of 21%). However, doping of tungsten beyond 5 wt% creates more recombination center for photogenerated electron–hole pairs, which deteriorates the photocatalytic performance. The W6+ ions function as electron receivers and avoid the recombination of electron–hole pairs. It was shown that OH. radicals are responsible for the ring opening reaction of aromatic MB.