Nanosized Ti–V mixed oxides: Effect of doping level in the photo-catalytic degradation of toluene using sunlight-type excitation

In this report we investigate the behavior of nanosized Ti–V mixed oxides with anatase structure in the photo-elimination of toluene using sunlight-type excitation. These systems were prepared by a microemulsion method and their physico-chemical properties characterized by a multitechnique approach using X-ray diffraction, electron paramagnetic resonance, Raman, and UV–vis spectroscopies. The preparation method allows the incorporation of significant amounts of vanadium in the anatase structure and two well-differentiated structural/electronic situations occur for samples having a V content below/above ca. 5 at.%. The photo-activity of the Ti–V samples reached a maximum for a sample having a vanadium content of ca. 2.5 at.%, which displays a reaction rate 2.3/2.7 times larger than the parent-TiO2/P25 references. The chemical/physical bases of such behavior are discussed in light of the characterization results.