The interactions NO-CO and O-2-NO-CO have been studied on CuCo2O4/gamma-Al2O3 and on gamma-Al2O3- and CuCo2O4/gamma-Al2O3-supported Pt, Rh and Pt-Rh catalysts. The deposition of noble metals (Pt, Rh and Pt-Rh) on CuCo2O4/gamma-Al2O3 instead of gamma-Al2O3 is beneficial in : lowering the temperature at which maximum N2O is formed and decreasing the maximum N2O concentration attained; lowering the onset temperature of NO to N-2 reduction, and increasing the N-2 selectivity; preserving the activity towards NO to N-2 reduction on a higher level following the concentration step NO + CO/O-2 + NO + CO and changing the conditions from stoichiometric to oxidizing (50% excess of oxidants). The reason for this behaviour of the CuCo2O4/gamma-Al2O3-based noble metal catalysts is the formation (reversible) of a reduced surface layer on the CuCo2O4 supported spinel under the conditions of a stoichiometric NO + CO mixture.