Mechanism of M ferrites (M = Cu and Ni) in the CO2 decomposition reaction

Abstract

M ferrites (M = Ni and Cu) were prepared for the CO2 decomposition reaction. The mechanisms of reduction and oxidation of M ferrites were investigated by thermogravimetric analysis and X-ray diffraction experiments, Cu ferrite showed excellent redox properties compared to those of Ni ferrite, Cu ferrite lost its oxygen atoms from the lattice lay the H-2 reduction at 473 K, which was 150 K lower than the temperature at which Ni ferrite did. The reduction of Cu ferrite at 1073 K formed the mixture of metallic Cu, FeO, and alpha -Fe, while Ni ferrite gave a Ni-Fe alloy at the same temperature. Reaction of the reduced ferrites with CO2 oxidized the ferrites by suppling oxygen atoms from CO2. The oxidation temperature of the reduced Cu ferrite was 200 K lower, and the weight recovery was faster than that of Ni ferrite. The oxidation with CO2 at 1073 K could not regenerate their original states and produced the mixture of Fe3O4 and metallic Cu and Ni, On the basis of the understanding of the Cu ferrite redox behaviors, a new mechanism for the CO2 decomposition reaction was proposed.