ENHANCED PHOTOCATALYTIC ACTIVITY OF TI1-XVXO2 SOLID-SOLUTION ON THE DEGRADATION OF ACETONE

Solid solutions of Ti1-xVxO2 (0.00 < x less than or equal to 0.025) ex hibit higher photocatalytic activity than pure TiO2, for the oxidation of acetone. Results from X-ray photoelectron spectrometry, X-ray diff ractometry and photoionization detection reveal that the photocatalyti c activity of the solid solution increases with increasing V substitut ion, but decreases with a decrease in the anatase to rutile ratio. The optimum composition in terms of activity is x = 0.015, with an anatas e to rutile ratio of 9 : 1. Zeta potential measurements indicate that the isoelectric point (in terms of the pH value) is affected by the am ount of V substitution. The catalyst with x = 0.015 has the lowest iso electric point (at pH 5.5). All these results suggest that V substitut ion may enhance the adsorption of hydroxide ions onto the surface of t he catalyst. More hydroxyl radicals can be generated, resulting in a h igher photocatalytic activity. The synthesis of the catalyst and the e ffect of the crystalline form of the catalyst on its activity are also presented. (C) 1997 Elsevier Science S.A.