Modification of V2O5-WO3/TiO2 catalysts supported on SiC filter for NO reduction at low temperature

Abstract

The catalytic filter, a ceramic filter supported SCR catalyst, is a promising material for treating particulates and NOX simultaneously. Recently, it is found that a SiC filter supported V2O5WO3-TiO2 [commercial catalyst system] shows a reasonable SCR activity around 320 degrees C [1]. In order to improve its catalytic activity at low temperatures, the effects of Pt and MnOX addition on the catalytic filter are investigated. The macro-porous TiO2 film was firstly coated on the pore surface of SiC filter element using the solution composed of the preformed TiO2 particles (P25). Catalytic filters were prepared by the impregnation of TiO2 coated-SiC filter in the solution containing the catalyst components. The MnOX-added catalytic filter showed very wide temperature window from 150-340 degrees C, providing N-X slip concentration less than 20 ppm for the treatment of 700 ppm NO at a face velocity of 2 cm/s. Pt added-catalytic filter shifted the optimum working temperature towards the lower temperatures (180-240 degrees C) compared to the one without Pt (280-330 degrees C). It is understood that MnOX in the catalyst system roles as the main catalyst component while Pt rose as a electron modification additive.