CATALYST CONTAINING PLATINUM ON A SUPPORT CONSISTING OF MAGNESIUM OXIDE AND CERIUM OXIDE FOR THE REDUCTION OF NO TO N2 WITH HYDROGEN UNDER NOx OXIDATION CONDITIONS

摘要

The invention relates to a novel catalyst having excellent activity, selectivity and stability for reducing nitric oxide to gas nitrogen, with hydrogen being used as a reducing agent, in the low temperature range 100-200 DEG C and in the presence of an excess of oxygen (e.g. 5 % vol), H2O (5 % vol) and/or SO2 (20 ppm) in the supply. The inventive catalyst consists of platinum crystals which are in contact with the phases of a mixed MgO and CeO2 medium or in the form of platinum supported on the mixed MgO-CeO2 medium which has already been sulphated in a selective manner. The Pt/MgO-CeO2 catalyst can be used to obtain NO conversion levels which are greater than 40 % and nitrogen selectivity values of greater than 80 % under NOx oxidation conditions in the 100-400 DEG C temperature range and for a surface contact time of 0.045 s. In particular, full NO conversion is obtained as well as N2 selectivity levels of 83 % at 150 DEG C with a reaction mixture of 0.25 % NO / 1 % H2 / 5 % O2 / 5 % H2O / He.