Abstract

Catalytic filters for the simultaneous removal of soot and nitrogen oxides were prepared by means of coating cordierite monoliths with alumina-based suspensions containing Cu, Co or V and K as the catalytically active phase. Textural and chemical properties of the coated monoliths were determined by means of N 2-physisorption, XRD, SEM-EDX and temperature programmed reduction. Activity of the catalytic filters in the simultaneous removal of soot and nitrogen oxides was tested in a fixed bed installation in absence and in presence of steam and CO 2. Complete soot oxidation was measured for some of the assayed catalytic filters, with high selectivity to CO 2 formation. NO reduction was preceded by a peak of NO 2 formation, which corresponded to maximum soot oxidation rate, pointing to the formation of NO 2 as a key step in the reaction mechanism for the simultaneous removal. Presence of steam and CO 2 diminished catalytic activity and selectivity for soot oxidation. © 2011 Elsevier B.V.