Promoting Effect of Coexisting H2O on the Activity of Ir/WO3/SiO2Catalyst for the Selective Reduction of NO with CO

The catalytic activity of Ir/WO3/SiO2 for the selective reduction of NO with CO (CO-SCR) in the presence of excess O2 was significantly increased by the presence of coexisting H2O, whereas NO reduction hardly occurred in the absence of H2O. Coexisting H2O plays an important role preventing catalyst deactivation caused by oxidation of the catalytically active Ir sites at high temperatures.