CO 2 decomposition over freshly reduced nanocrystalline Fe 2O 3

Abstract

The decomposition of CO 2 was investigated as a process of both industrial and environmental considerable importance. Nanocrystallines Fe 2O 3 was obtained by the thermal evaporation of iron acetate. Fe 2O 3 compacts were isothermally reduced in H 2 flow at 450–600 °C. The isothermal reduction profiles obtained in this study showed that the reaction proceeded through a topochemical mode of reduction. Metallic iron produced from the complete reduction of nanocrystallines Fe 2O 3, were subjected to direct reoxidation in CO 2 flow at 400–600 °C. CO 2 decomposed to carbon nanotubes during the reoxidation of freshly reduced nanocrystallines Fe 2O 3. The reoxidation process was found to be mainly governed by both the reduction and reoxidation temperatures. The prepared, completely reduced and reoxidized Fe 2O 3 compacts, were characterized by X-ray diffraction analysis, scanning electron microscopy and reflected light microscope examinations. For the reoxidation process, it was found that the initial reaction stages were controlled by the interfacial chemical reaction mechanism. On the other hand at the intermediate and final stages the mechanism by which the reoxidation process proceeded was found to be the solid-state diffusion.