MOSSBAUER STUDY OF OXYGEN-DEFICIENT ZN(II)-BEARING FERRITES (ZNXFE3-XO4-DELTA, O-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1) AND THEIRREACTIVITY TOWARD CO2 DECOMPOSITION TO CARBON

Oxygen-deficient Zn(II)-bearing ferrites (ZnxFe3-xO4-delta 0 less-than -or-equal-to X less-than-or-equal-to 1, delta > 0) have been synthesiz ed and studied for their reactivity in the decomposition of CO2 to car bon at 300-degrees-C. They were prepared by reducing Zn(II)-bearing fe rrites with H-2 gas at 300-degrees-C. The oxygen-deficient Zn(II)-bear ing ferrites consisted of a single phase of a spinel-type structure wh ich was oxygen-deficient compared with stoichiometric composition. The ir lattice constants were larger than those of the corresponding stoic hiometric spinel. Decomposition of CO2 to carbon was accompanied by an oxidation of the oxygen-deficient Zn(II)-bearing ferrite. The amount of carbon deposited on the solid decreased when the Zn content in the Zn(II)-bearing ferrite increased. The decrease in decomposition rate i s due to changes in the electron conductivity according to the Zn cont ent in the Zn(II)-bearing ferrite. These changes may contribute to its reactivity for decomposition of the CO2 to carbon.