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

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 ferrit e showed excellent redox properties compared to those of Ni ferrite, Cu fer rite 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 re duction 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. Re action of the reduced ferrites with CO2 oxidized the ferrites by suppling o xygen atoms from CO2. The oxidation temperature of the reduced Cu ferrite w as 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 state s 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 t he CO2 decomposition reaction was proposed.