M-Doped TiO2 and TiO2-MxOy Mixed Oxides (M = V, Bi, W) by Reactive Mineralization of Cellulose - Evaluation of Their Photocatalytic Activity
Résumé
M-doped TiO2 and mixed oxides MxOy-TiO2 (M = V, Bi, W) were synthesized by the reactive mineralization of ash-free filter paper under anhyd. conditions. Mixts. of metal chlorides (TiCl4 with VOCl3, WCl6, or BiCl3) were reacted directly with cellulose, and three different Ti/M at. ratios were used (99, 19, and 9). The resulting materials consist of original nanoflower assemblies of needle-shaped primary particles. Their physicochem. characteristics were investigated by various techniques (x-ray diffraction, diffuse-reflectance UV/visible spectroscopy, electron microscopy, and elemental anal.). The incorporation of the doping metal or the formation of mixt. of oxides with TiO2 (WO3, Bi2O3) depends on the metal and the proportions used. The photocatalytic activities of the materials were tested for the degrdn. of phenol. The vanadium-doped materials exhibit true solid-soln. formation and their band gaps shift into the visible range.