On the Pt/V/MCM-41 catalyst with 1wt% Pt and 4wt% V, the maximum conversion of NO reduction into N2+N2O by C3H6 was about 73%, which was 10% higher than on 1wt% Pt/silica, and this maximum conversion was maintained over a temperature range of 70.DEG.C. between 270 and 340.DEG.C.. (author abst.)