Reduction of NO 2 in Flue Gas by CO and Propylene over CuO‐CeO 2 /SiO 2 in the Presence of O 2

Catalytic reduction of NO 2 with CO and/or propylene in the presence of NO and excess oxygen, a model mixture for flue gas, was studied over a series of CuO‐CeO 2 /SiO 2 catalysts between 120–260 °C. The effect of HCl, an impurity in flue gas, on the activity of the catalysts was evaluated. It was found that a binary oxide catalyst, 2% CuO‐8% CeO 2 /SiO 2 , was active for the reduction of NO 2 by CO and/or propylene. CO was effective for selective reduction of NO 2 in the presence of NO and O 2 in a temperature window between 160–200 °C while propylene was effective at temperature higher than 200 °C. In the presence of HCl, the activity of the catalyst for reduction of NO 2 with CO was irreversibly deactivated. However, the activity for reduction of NO 2 with propylene was not influenced by HCl.