Catalytic decomposition of N2O and catalytic reduction of N2O and N2O + NO by NH3 in the presence of O2 over Fe-zeolite

The decomposition of N₂O, and the catalytic reduction by NH₃ of N₂O and N₂O + NO, have been studied on Fe-BEA, -ZSM-5 and -FER catalysts. These catalysts were prepared by classical ion exchange and characterized by TPR after various activation treatments. Fe-FER is the most active material in the catalytic decomposition because “oxo-species” reducible at low temperature, appearing upon interaction of Fe^II-zeolite with N₂O (-oxygen), are formed in largest amounts with this material. The decomposition of N₂O is promoted by addition of NH₃, and even more with NH₃ + NO in the case of Fe-FER and -BEA. It is proposed that the NO-promoted reduction of N₂O originated from the fast surface reaction between -oxygen O^* and NO^* to yield NO₂^*, which in turn reacts immediately with NH₃.