Hybrid photocatalysts for the degradation of trichloroethylene in air

Abstract

Hybrid photocatalysts based on an adsorbent SiMgOx and a photocatalyst TiO 2 were developed in a plate shape. The ceramic surface was coated with TiO 2 by the slip-casting technique. The effect of the support in the photocatalytic degradation of trichloroethylene (TCE) was analyzed by modifying TiO 2 loading and the layer thickness. Photocatalysts were characterised by N 2 adsorption–desorption, mercury intrusion porosimetry, SEM, UV–vis spectroscopy and XRD. A direct relationship between the TiO 2 content and the photocatalytic activity was observed up to three layers of TiO 2 (0.66 wt.%). Our results indicate that intermediate species generated on the TiO 2 layer can migrate through relatively long distances to react with the OH − surface groups of the support. By increasing the TiO 2 loading of the photocatalyst two effects were observed: trichloroethylene conversion is enhanced, while the efficiency of the oxidation process is decreased at expenses of increasing the selectivity to COCl 2 and dichloroacetylchloride (DCAC). The results are discussed in terms of the layer thickness, TiO 2 amount, TCE conversion and CO 2, and COCl 2 selectivity.