Abstract: The process comprises the step of passing the nitrogen oxides through a zone maintained at conditions at which said nitrogen oxides will be reduced, said zone including a substantially rigid catalytic member of a metal support or substrate plated with one or more members selected from the group consisting of copper, nickel, iron, and chromium and having, at least in part, an oxidized surface that catalytically promotes the reduction of the oxides of nitrogen as they pass through said zone.

Abstract: The catalyst comprises a catalytic surface of one or more metallic oxides formed on a substantially rigid, reticulated support or substrate of a tough, strong metal or metal alloy having a melting point in excess of about 2,000.degree. F. The oxides are those of one or more members selected from the group consisting of copper, nickel, iron and chromium.The catalyst is prepared by the method comprising the steps of: (a) plating the surface of the support or substrate with one or more layers of one or more of the members to form a plated support or substrate, (b) heating in an inert atmosphere the plated support or substrate so that the atoms on the surfaces of the members interdiffuse with themselves and with surface atoms of the support or substrate, and (c) exposing the plated support or substrate to oxidizing conditions to oxidize, at least in part, the atoms at or near the surface of the plated support or substrate to form thereat oxides of the members.

Abstract: The process comprises passing the exhaust gas through a reduction zone containing a catalyst comprising a nickel component, a rhodium component, and a monolithic ceramic support and being maintained at a temperature of about 700.degree. to about 1,800.degree. F. The catalyst may also contain a platinum component and/or a palladium component and the monolithic ceramic support may be coated with a wash coat of a ceramic material having a relatively high surface area. The nickel component and the rhodium component are deposited upon the monolithic ceramic support sequentially and in that order.

Abstract: The catalyst comprises a nickel component, a rhodium component, and a monolithic ceramic support. It may also contain a platinum component and/or a palladium component and the monolithic ceramic support may be coated with a wash coat of a ceramic material having a relatively high surface area. The nickel component and the rhodium component are deposited upon the monolithic ceramic support sequentially and in that order.The method of catalyst preparation and a process using such catalyst are also disclosed.