Enhancement of TiO2/C photocatalytic activity by sulfate promotion

TiO2/C systems prepared in the presence of increasing active carbon (AC) content have been sulfate promoted. Synergetic effect of active carbon and surface sulfate produces a significant stabilization of the anatase crystalline phase at high temperature. From thermogravimetric (TG) and XPS analysis, sulfate and carbon content can be considered negligible. The improved photocatalytic activities for phenol degradation of TiO2 systems seem to be related with the anatase stabilization at high temperature with low surface O/Ti ratio. In this sense, it seems that the presence of active carbon delay the surface sulfates elimination. Consequently, the stabilisation of the anatase phase by surface anchored sulfate becomes more evident. On the other hand, acid treatment produces a low O/Ti surface that could be also responsible of the improved photocatalytic activities of TCS sample. Reaction rates per surface area indicate an enhancement of the photocatalytic activity of TC and TCS series with respect to Degussa P25. (C) 2003 Elsevier B.V. All rights reserved.