Résumé
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•CuO supported on MgO, Al2O3 and MgAlO catalysts were compared.•The most reducible CuO species were involved in the methane combustion.•Both strong acid and basic sites lead to higher catalytic activity.•The most active catalyst corresponds to CuO on a mixture of γ-alumina and periclase phases.
Copper oxide supported on Al2O3, MgO and Mg(Al)O mixed oxides with Mg/Al atomic ratios of 1, 3 and 5 were prepared by coprecipitation followed by calcination at 750°C. These catalysts have been characterized by XRD, EDX, N2 adsorption, TG-DTG, NH3-TPD, CO2-TPD and H2-TPR, and their catalytic properties in the total oxidation of methane were investigated. Correlations between the physico-chemical properties and the catalytic activities were established. The best activity was obtained for the catalyst presenting a distribution of CuO species going from well distributed and aggregated CuO particles to CuAl2O4 phase on a Mg(Al)O support composed of a mixture of γ-alumina and periclase phases. It also possesses high relative amounts of strong acid and of medium and strong basic sites in this series. All the catalysts tested exhibited very good stabilities for the reaction conditions chosen and time-on-stream up to more than 50h.