Development of novel TiO2 sol-gel-derived composite and its photocatalytic activities for trichloroethylene oxidation

A novel method for the processing of sol-gel-derived titanium dioxide composites has been developed and investigated for the purpose of producing thick films and self-supported photocatalysts. The processing of the composite sol-gel (CSG) photocatalysts, prepared as "coating" and self-supported "bulk" bodies involved utilizing precalcined commercial titania (Degussa P-25 and Aremco) as filler mixed with the sot and then, heat treatment at relatively low temperature (up to 700degreesC). The resulting photocatalyst exhibited relatively high surface area and enhanced mechanical stability and integrity. Scratch adhesion tests performed on the CSG photocatalysts showed very good mechanical integrity and scratch resistance of about 5-10 N, far greater than the 0-0.2 N observed for P-25 and Aremco photocatalysts. Photocatalytic activities of the developed composites were evaluated through the oxidation of a known and standard air contaminant trichloroethylene (TCE), which has been widely investigated by many researchers in the field of photocatalysis. The CSG photocatalysts coatings provided TCE removals ranging up to 90% of that provided by P-25. However, the better mechanical integrity offered by the CSG photocatalysts make them viable alternatives for commercial applications that require long term stability and good mechanical properties. (C) 2004 Elsevier B.V. All rights reserved.