A process for oxidizing and reducing with the use of platinum metal catalysts of the perovskite - type

摘要

1489786 Exhaust gas purification catalysts E I DU PONT DE NEMOURS & CO 10 Oct 1974 [10 Oct 1973 25 April 1974 26 April 1974] 43934/74 Heading B1E [Also in Division Cl] A catalyst which may be contacted with a gaseous stream comprising at least one oxidizable and one reducible component selected from O 2 , H 2 , CO, hydrocarbons and nitrogen oxides under conditions to convert the components into at least one of H 2 O, CO 2 , N 2 and NH 3 comprises a metal oxide having the general formula ABO 3 and a perovskite crystal structure in which from 1% to 50% of the B cation sites are occupied by cations of a platinum group metal, wherein the B cation sites have at least one of the following composition characteristics: (a) at least 5% of the non platinum group B cation sites are occupied by a metal present in a first valence and at least 5% of the non platinum group B sites are occupied by the same metal present in a second valence; (b) the platinum group metal is platinum, palladium or rhodium; (c) a major proportion of the non platinum group B sites are occupied by the ions of aluminium; and (d) the non platinum group B sites are occupied by ions consisting essentially of trivalent iron, cobalt or nickel. Reference is made to Specification 1489785.