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NO conversion to N 2 in the presence of methane and oxygen over 0.03 at.% Rh/Al 2 O 3 , 0.51 at.% Pt/Al 2 O 3 and 0.34 at.% Pt-0.03 at.% Rh/Al 2 O 3 catalysts was investigated. δ-Alumina and precious metal-aluminum alloy phases were revealed by XRD and HRTEM in the catalysts. The results of the catalytic activity investigations, with temperature-programmed as well as steady-state methods, showed that NO decomposition occurs at a reasonable rate on the alloy surfaces at temperatures up to 623 K whereas some CH 4 deNO x takes place on δ-alumina above this temperature. A mechanism for the NO decomposition is proposed herein. It is based on NO adsorption on the precious metal atoms followed by the transfer of electrons from alloy to antibonding π orbitals of NO (ads.) molecules. The CH 4 deNO x was shown to occur according to an earlier proposed mechanism, via methane oxidation by NO 2(ads.) to oxygenates and then NO reduction by oxygenates to N 2 .