Porous Vanadium/Titanium Oxides—Synthesis, Characterization, and Photocatalytic Activity

Abstract

Sol–gel chemistry and a templating technique were combined for the synthesis of vanadium/titanium oxides with controlled porous structure and various quantities of vanadium (0–9.7 at-%). The specific surface area of the porous vanadium/titanium oxides increased with increasing vanadium content to a maximum of 72 m2 g–1 at 6.6 at-% V, with a corresponding decrease in anatase crystal size (minimum of 12.4 nm), and c-axis lattice parameter (0.9475 nm). The optical band-gap decreased substantially from 3.10 eV for TiO2 to 2.53 eV on the addition of 9.7 at-% V. The adsorption capability of the oxides for aqueous methylene blue (pH ~6) increased significantly with increasing vanadium content (26.7 to 318.9 mg L–1 g–1 for 0 to 9.7 at-% V). The photodegradation of methylene blue was most efficient with the 0.9 at-% V-TiO2 sample for both UV and visible light irradiation.