The catalytic activity of CuOx/ZrO2 for the abatement of NO with propene or ammonia in the presence of O-2

Samples CuOx/ZrO2 (0.1-8.4 Cu atoms nm(-2)) were prepared by adsorption or impregnation methods. The characterisation of samples by means of XPS, XRD, DRS, ESR, IR and volumetric adsorption of CO, showed copper dispersion up to 2.5 atoms nm(-2), and the presence of CuO in samples with higher Cu cont ent. The selective catalytic reduction of NO with propene or ammonia in the presence of excess oxygen, was studied in a flow apparatus with reactant m ixtures of various composition (NO:C3H6 :O-2 = 0-4000 ppm: 100-2000 ppm: 0- 3.5%; and NO:NH3 :O-2 = 0-700 ppm:700 ppm:3.6%). With both propene and ammo nia, CuOx/ZrO2 catalysts containing up to 2.5 Cu atoms nm(-2) were active, selective and stable as a function of the time on stream. On all catalysts, with ammonia as reducing agents, up to 523 K, NO conversion equalled NH3 c onversion leading to 100% selectivity. With both propene and ammonia, NO mo lecules that were converted to Nz per Cu atom and per second were nearly in dependent of the Cu content up to 2.5 Cu atoms nm(-2). (C) 1999 Elsevier Sc ience B.V. All rights reserved.