CO2 absorption properties and characterization of perovskite oxides, (Ba,Ca) (Co,Fe) O3−δ Original Research Article

Perovskite oxides, Ba0.95Ca0.05Co1−xFexO3−δ, were found to be useful as materials for CO2 absorption at high temperatures between 900 to 1123 K, and CO2 absorbed perovskite oxides were characterized by Mössbauer spectrometry. Before absorption of CO2, a magnetic sextet with sharp peaks and two paramagnetic doublets due to Fe3+ and Fe4+ were observed for the cubic oxides with x > 0.4. Perovskite oxides with lattice oxygen vacancies, which were produced at high temperature, easily absorbed CO2. After absorption of CO2, the paramagnetic peaks disappeared and magnetic fields were produced due to less interaction of lattice oxygens with iron atoms, where CO2 reacted with lattice oxygen to form CO3− ions. Finally only one magnetic sextet with sharp peaks remained. It was considered to be due to α-Fe2O3 with a small magnetic field, dispersed in BaCO3 matrix.