CO2 DECOMPOSITION TO CARBON WITH FERRITE-DERIVED METALLIC PHASE AT 300-DEGREES-C

CO2 decomposition to carbon was studied on alpha-Fe and Fe-Ni alloy formed by H-2-reduction of magnetite and Ni(II)-bearing ferrite at 300 degrees C. The metallic phases were transformed to ferrite phase by incorporating oxygen from CO2. The integrated amount of decomposed CO2 reached 30 mmol CO2 g(-1) of Fe3O4 by repeating the H-2 reduction and CO2 decomposition 9 times. The decomposition of CO2 on the H-2-reduced magnetite was kept nearly constant at 72-86%, irrespective of the run number. A small portion of the alpha-Fe was transformed to carbide in the Ist run; however, the formation of carbide scarcely proceeded by repeating these processes on magnetite. The decomposition reactivity of H-2-reduced Ni(II)-bearing ferrite decreased gradually. The integrated amount of decomposed CO2 was 20 mmol CO2 g(-1) of Ni0.39Fe2.61O4 by repeating the processes 11 times. For Ni(II)-bearing ferrite, the formation of carbide proceeded more effectively. The lower reactivity of H-2-reduced Ni(II)-bearing ferrite for CO, decomposition will be due to the formation of carbide.