2 wt% Ag- and 2 wt% Ag-1.5 wt% Nb mesoporous alumina catalysts were prepared by non-hydrolytic sol-gel process. Silver accessibility is enhanced by calcination at high temperature. By performing calcination in presence of water vapour, silver particles are well dispersed and interact more strongly with the alumina surface and activity in n-decane-SCR of NOx is greatly improved. Moreover, the addition of niobium in the starting material leads to more efficient catalysts and enhances mainly the low temperature activity. (C) 2013 Published by Elsevier B.V.