CO2 decomposition to carbon with ferrite-derived metallic phase at 300 °C Original Research Article

CO2 decomposition to carbon was studied on α-Fe and Fe-Ni alloy formed by H2-reduction of magnetite and Ni(II)-bearing ferrite at 300 °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 H2 reduction and CO2 decomposition 9 times. The decomposition of CO2 on the H2-reduced magnetite was kept nearly constant at 72–86%, irrespective of the run number. A small portion of the α-Fe was transformed to carbide in the 1st run; however, the formation of carbide scarcely proceeded by repeating these processes on magnetite. The decomposition reactivity of H2-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 H2-reduced Ni(II)-bearing ferrite for CO2 decomposition will be due to the formation of carbide.