Catalytic combustion of methane over La2BCoO6perovskites containing Ni, Cu and Fe: impact of B-sites on oxygen species and catalytic activity

The effect of B-site partial substitution on the structure and the catalytic performance of cobalt-based double perovskites (La(2)BCoO(6)where B = Cu, Ni and Fe) was investigated in the catalytic combustion of methane. The synthesized samples were characterized using XRD, XRF, N-2-physisorption, H-2-TPR, O-2-TPD, CH4-TPR and XPS techniques. The XRD results showed the successful synthesis of cobalt-based double perovskites with single phase and rhombohedral structure. The incorporation of Ni, Cu and Fe created abundant oxygen vacancies on the double perovskites which improved oxygen mobility and reducibility and accordingly increased the catalytic activity. The catalytic activity of synthesized samples was in the order of La2CuCoO6 > La2NiCoO6 > La2FeCoO6 > LaCoO3. The better activity of La(2)CuCoO(6)was owing to the presence of the highest oxygen species, the highest reducibility and the highest oxygen mobility.