Abstract: A method for the catalytic removal of nitrogen oxides, methane and carbon monoxide out of oxygen-rich exhaust gases emitted from motors that may combust natural gas by contacting the exhaust gas with a zeolite of the NFI structure that contains palladium. The palladium containing zeolite has been activated under oxygen prior to use by calcining the palladium containing zeolite at about 300.degree. C. for about one hour, then calcining the palladium containing zeolite at about 500.degree. C. for about one hour, and cooling the palladium containing zeolite to about 300.degree. C.

Abstract: The present invention concerns a non selective oxidation catalyst resistant to high temperatures and a method of preparation of this catalyst.According to the invention, this catalyst comprises an essentially alumina-based support stabilized with silicon and a precursor of the active phase consisting of a noble metal M in which the active phase is cationic amino-complex of the [M(NH.sub.3).sub.4 ].sup.++ type or a compound selected among the tetrachloropalladic acid.The catalyst of the invention is usable in particular in processes of catalytic combustion of hydrocarbons, of carbone monoxide, of hydrogen or of their mixtures.