Mixed spinel-type Ni-Co-Mn oxides: synthesis, structure and catalytic properties

Abstract

Abstract Mixed spinel-type oxides Co1.8Mn1.2O4, Ni0.33Co1.33Mn1.33O4 and Ni0.6Co1.2Mn1.2O4 prepared by thermal decomposition of nitrates have been studied in ethanol steam reforming reaction. Ni0.6Co1.2Mn1.2O4 demonstrated the highest activity among the oxides tested. Specificity of the cation distribution in the samples and their oxygen mobility have been studied by X-ray absorption spectroscopy and oxygen isotope heteroexchange, respectively. Doping of mixed cobalt-manganese spinel with Ni results in Mn redistribution between 3+ and 4+ oxidation states, thus increasing oxygen diffusion coefficient and the catalytic activity.