The influence of surface properties on the photocatalytic activity of nanostructured TiO_2

摘要

Nanostructured TiO_2 with 11-(P11) and 5-nm (P5) crystal sizes were prepared by a modified sol-gel method Controlled crystallization and a pretreatment process were exployed to obtain TiO_2 with different surface roughness and degree of hydroxylation which mainataining an identical crystal (i.e.,11 or 5 nm) and aggrepate (i.e.,100 nm) sizes phase structure (i.e.,anatase) and crystallinity (i.e.,X-ray diffraction peak intensity) Using the photooxidationof airborne trichloroethylene as a probe reaction we were able to identify that teh hydroxyl groups on low-coordinated titanium atoms are responsible for the generation of dichlorethylene adn dichloroacetaldehyde by-products Their presence usually means lower TCE conversion and in some cases leads to catalyst deactivation.