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) exhibit higher photocatalytic activity than pure TiO2, for the oxidation of acetone. Results from X-ray photoelectron spectrometry, X-ray diffractometry and photoionization detection reveal that the photocatalytic activity of the solid solution increases with increasing V substitution, but decreases with a decrease in the anatase to rutile ratio. The optimum composition in terms of activity is x = 0.015, with an anatase to rutile ratio of 9 : 1. Zeta potential measurements indicate that the isoelectric point (in terms of the pH value) is affected by the amount of V substitution. The catalyst with x = 0.015 has the lowest isoelectric point (at pH 5.5). All these results suggest that V substitution may enhance the adsorption of hydroxide ions onto the surface of the catalyst. More hydroxyl radicals can be generated, resulting in a higher photocatalytic activity. The synthesis of the catalyst and the effect of the crystalline form of the catalyst on its activity are also presented. (C) 1997 Elsevier Science S.A.