CO 2 decomposition over freshly reduced nano-crystallite Cu 0.5Zn 0.5Fe 2O 4 at 400–600 °C

Abstract

The decomposition of CO 2 was investigated as a process of both industrial and environmental importance. The decomposition of CO 2 over nano-crystalline oxygen-deficient Cu 0.5Zn 0.5Fe 2O 4 was tested through simultaneously reduction–reoxidation technique. The experiments were carried out isothermally using thermo-gravimetric apparatus. The prepared, completely reduced and reoxidized Cu 0.5Zn 0.5Fe 2O 4 compacts were characterized by XRD, SEM, TEM, carbon content analysis and reflected light microscope. The influence of the experimental conditions on the structural characteristics of the products was extensively studied to get clear comprehension of re-oxidation process. The experimental measurements were used to elucidate the re-oxidation mechanism under isothermal conditions. For the re-oxidation process, it was found that at the initial stages, the reaction is controlled by the interfacial chemical reaction mechanism with some contribution to the gaseous diffusion mechanism. On the other hand, the mechanism of reaction was found to be solid-state diffusion at the final stages. Carbon nanotubes were extensively formed on the surface of the reduced samples as a result of the decomposition of CO 2.