A Highly Active Ir/WO3 Catalyst for the Selective Reduction of NO by CO in the Presence of O2 or O2+ SO2

Ir/WO3 catalyst is highly active for the reduction of NO by CO even in the presence of either O2 or O2 + SO2. However, the activity of Ir/WO3 is fairly lowered by the presence of SO2 alone. It is believed that the active sites lose their activity by the adsorption of SO2 but O2 promotes the desorption of SO2 from these sites as suggested by TPD, thus the negative effect of SO2 being suppressed by the coexistence of O2