Deactivation and regeneration of titania catalyst supported on glass fiber in the photocatalytic degradation of toluene

Abstract

Two titania photocatalysts supported on glass fiber (GF) were prepared by using anatase-type crystalline P25 powder and dilute titanium isopropoxide solution (DTS). Chemical compositions and characteristics of the surface of the P25/GF and DTS/GF catalysts were examined with an XPS method, and their activities in the photocatalytic degradation of toluene under UV irradiation were discussed. Although a large amount of titania was stably impregnated on glass fiber on the DTS/GF catalyst, low-temperature calcination brought about insufficient oxidation of titanium atoms resulting in a heavy deposit of carbonaceous materials. Both catalysts (P25/GF and DTS/GF) were active in photocatalytic degradation, while their catalytic activity was lowered because of the accumulation of reactant and carbonaceous materials on the surface. Hydrogen peroxide completely regenerated the deactivated P25/GF catalyst by removing contaminants. However, the activity of the used DTS/GF catalyst was considerably enhanced by exposing it to hydrogen peroxide vapor to a level higher than the fresh catalyst due to the increase in the surface concentration of active oxidizing species as well as the removal of carbonaceous materials.