ROLE OF PROPENE IN THE SELECTIVE REDUCTION OF NITROGEN MONOXIDE IN COPPER-EXCHANGED ZEOLITES

Gas switching experiments, examining the first few minutes of reaction, have been used to study the selective reduction of nitrogen monoxide by propene on a Cu-ZSM-5 catalyst in an oxygen-rich gas mixture. It has been found that the conversion of nitrogen monoxide to nitrogen reaches a steady-state activity in a very short period of time. It is concluded that carbon deposition is not responsible for the conversion of nitrogen monoxide into nitrogen. It is proposed instead that the hydrocarbon and oxygen act to maintain the active copper sites in an oxidation state suitable for direct nitrogen monoxide decomposition.