Comparative investigation of simultaneous removal of NO and N2O on supported Pt catalysts: effect of thermal ageing

Introduction The abatement of NOx and N2O is a great challenge for stationary source applications since no catalytic formulation active at moderate temperature around 300°C can remove both pollutants from exhaust gas simultaneously in a complex atmosphere. The replacement of ammonia by hydrogen as reducing agent has many potential applications as suggested by recent studies which show high efficiency for NOx conversion at low temperature on Pt/La0.7Sr0.2Ce0.1FeO3 [1]. Noble metals are currently used for such applications but generally suffer from a poor selectivity in O2 excess. It was also found that the perovskite structure is able to preserve a high degree of dispersion in severe temperature conditions [2]. Unfortunately, no relevant comparison with alumina based catalysts is available in the literature. Our work was focused on the comparison of Pt/Al2O3 and Pt/LaFeO3 catalysts before and after several thermal treatments including ageing under reaction conditions. The influence of the support and metal loading was investigated and characterised with TPR, XPS, TEM and temperature-programmed reaction under the following mixture of He+0.1%NO+0.1%N2O+0.5%H2+0.5%H2O +3%O2. Ageing thermal treatments were applied under reaction mixture at 500°C overnight.