he class of transition metal oxides drives attention of many researchers, particularly when the preparation of photocatalyst devices is concerned. In the last years, tungsten oxide has been highlighted due to its band gap, smaller than that of titanium oxide, which therefore allows the absorption of radiation by the tungsten oxide to occur in the visible region of the electromagnetic spectrum.1 The capacity to achieve different oxidation states (–II to +VI)2,3 permits the obtainment of different kinds of materials with changes in stoichiometry and structuration.4,5 Szilágyi et al.6 studied hexagonal (h-) and monoclinic (m-) tungsten oxide in oxidized and reduced forms and found that the oxidized species present improved photocatalytic performance compared to the reduced form.