Emission and Transmission Mössbauer Spectroscopic (EMS and TMS) Study of Perovskite Oxides, (Ba, Ca)(Fe, Co)O3-δ, Absorbed with CO2

Perovskite oxides, (Ba0.95,Ca0.05) (Co1-x,Fex) O3-δ, are prominent materials for CO2 absorption at high temperature. The substitution of Ba sites with Ca ion, and the mixed valence states of Fe and Co ions due to the formation of oxygen vacancies at high temperatures are effective for CO2 absorption. Especially Co ions are more active for CO absorption than Fe ions. These oxides were analyzed by EMS and TMS before and after treatment in CO2 atmospheres. The difference between EMS and TMS spectra is found to be observed not only due to the oxygen affinity, but also to the different reactivity of Co and Fe ions in the B site towards CO2.