Total oxidation of benzene and chlorobenzene with MoO 3- and WO 3-promoted V 2O 5/TiO 2 catalysts prepared by a nonhydrolytic sol–gel route

Abstract

Vanadia–titania oxidation catalysts are highly regarded for the abatement of persistent air pollutants including aromatics, chlorinated aromatics, furans and dioxins in gas effluents. Molybdenum and tungsten oxides are recognized as efficient promoters enhancing the efficiency of vanadia-based catalysts. Classical approaches for the preparation of promoted catalysts involve multi-step processes. Here, binary and ternary mixed oxide xerogels are formed in one step by nonhydrolytic condensation reactions of chloride precursors in non-aqueous medium. Calcination was applied to provoke the migration of active and promoting oxides toward the surface, leading to well-spread vanadium, molybdenum and tungsten oxide species on the surface of anatase particles. The resulting catalysts are mesoporous and their composition is precisely controlled, confirming the versatility and reliability of the preparation route. The samples perform well in the deep oxidation of benzene and chlorobenzene, chosen as model volatile organic compounds (VOC). The performances of ternary catalysts systematically exceed those of binary V 2O 5-TiO 2, highlighting the promoting effect of WO 3 and MoO 3.