Abstract: A catalyst is made of at least two metal foil strips, the transverse corrugations having been formed in at least one of them. The metal foil strips are formed into a honeycomb containing channels. The strips are coated with a support or with supports, and at least one catalytically active agent such as a noble metal is added to the coated strips in order to produce a catalytic surface. In this case the catalytic surface has the physical structure derived from the coating. The honeycomb has at least two catalytic surfaces differing from each other with respect to at least the support or the physical structure.

Abstract: The invention relates to a method for impregnating alumina-containing catalyst support with platinum. In the method a platinum-containing solution is prepared by using a compound which contains bivalent platinum. The method comprises a stage during which the said platinum-containing solution is oxidized in order to form a solution which contains tetravalent platinum, from which solution platinum is adsorbed on the support.

Abstract: The invention relates to a catalyst intended for purifying diesel exhaust gases, the catalyst comprising a honeycomb and a support which has been prepared by using titanium dioxide and an inorganic sol, and at least one catalytically active agent.