Selective catalytic reduction of NOx with methane over indium supported on tungstated zirconia

Selective catalytic reduction (SCR) of NOx with methane was investigated over a series of non-noble metal (cobalt, manganese, nickel, tin, silver, indium) catalysts supported on tungstated zirconia (WZr). A great improvement of catalytic activity was found over the indium-loaded WZr catalysts upon the other WZr. The highest NOx conversion of 70% was achieved over an 1%In/WZr catalyst at 450 °C and 12,000 h−1. InO+ was proposed to be the active site in NO reduction. H2O and SO2 significantly inhibited NO reduction by competing with reactants to adsorb on InO+ site and forming inactive In(OH)2+ and In(SO3)+ species.