Methane as alternative in the selective reduction of NO over supported palladium catalysts in lean conditions:role of redox properties of support materials

摘要

The reduction of CH_4 by NO has been investigated in the presence of oxygen on palladium supported on alumina,ceriazirconia mixed oxides and perovskite materials,mainly LaCoO_3.The activation procedure,under oxygen or hydrogen,drastically influences the catalytic performances of both catalysts.The stabilisation of a metallic or oxidic Pd phase leads to poor activity in the conversion of NO in the absence of oxygen.On the other hand,oxygen enhances the activity,particularly on the reduced Pd/ LaCoO_3,in the CH_4+NO reaction.Such results have been explained by different interactions between palladium and the support.