Photocatalytic degradation of p-cresol on Pt/γAl2O3–TiO2 mixed oxides: Effect of oxidizing and reducing pre-treatments

Pt/γAl2O3–TiO2 photocatalysts were prepared by wet impregnation and tested in the photodegradation of p-cresol. The γAl2O3–TiO2 (5, 10 and 20 wt% TiO2) mixed oxides were prepared by simultaneous hydrolysis of boehmite and titanium alkoxide. The solids were characterized by nitrogen adsorption (BET surface area), XRD, UV–vis, FTIR-CO spectroscopy and TOC determinations. The mixed oxides showed higher specific surface areas than those obtained with the TiO2 bare semiconductor. On the Pt/γAl2O3–TiO2 photocatalysts, it was observed that the anatase phase was stabilized and the Eg band was shifted to the blue region. In the p-cresol photodegradation the reduced-Pt/γAl2O3–TiO2 solids were more active than the calcined-Pt/γAl2O3–TiO2 photocatalysts. The formation of reduced Pt0 leads to a highest photoactivity for the p-cresol photodegradation by enhancing the electron–hole separation.