PALLADIUM-CONTAINING, CERIA-SUPPORTED PLATINUM CATALYST AND CATALYST ASSEMBLY INCLUDING THE SAME

摘要

A catalyst composition includes a catalytic materialcontaining a platinum catalytic component dispersed on abulk ceria and a palladium catalytic component; the palla-dium catalytic component may be dispersed either on theceria or on another support, such as an activated aluminasupport. The catalytic material, which may include a re-fractory binder, such as alumina, may be dispersed as awashcoat on a suitable carrier, e.g., a cordierite honey-comb-type carrier having a plurality of fine gas flowpassages extending therethrough. The bulk ceria may bestabilized with a zirconia stabilizer and/or a lanthanastabilizer. The catalyst composition has utility as anoxidation catalyst and as a three-way conversion catalyst.In the latter case, its activity for the reduction of ni-trogen oxides may optionally be supplemented either byadding a rhodium-containing catalytic overcoat or by pro-viding a catalyst assembly in which the above-describedcatalyst composition is placed in series with any suitablenitrogen oxides reduction catalyst.