METHANATION OF CO2 WITH H2-REDUCED MAGNETITE

The methanation reaction of CO2 was studied with H-2-reduced magnetite. A high conversion ratio of about 0.9 (in 30 min of the reaction time) with a selectivity of nearly 100% was obtained at 300-degrees-C and at 0.1 MPa for H2-reduced magnetite which had been prepared by passing H-2 gas for 1-5 h at 300-degrees-C. From the results of X-ray diffractometry and Mossbauer spectroscopy, and from chemical analysis of the deposited carbon, H-2-reduced magnetite is considered to decompose adsorbed CO2 into carbon, and to incorporate the oxygen of the CO2 into the spinel-type structure of the magnetite, associated with oxidation of the Fe2+ ion into Fe3+ ion in the magnetite. The high conversion ratio in the methanation reaction is considered to come from a higher reactivity of the elementary carbon deposited on the surface of the H-2-reduced magnetite.