A Study on the Redox Characteristics of Oxygen Carriers CaSnO₃ and Materials Partially Substituted with Co and Ce for Chemical Looping Combustion

As a transition metal to be used for oxygen carrier, Sn-based oxides were expected to have high theoretical oxygen transfer capacity and have potential, and despite the low melting point, cycle stability was secured by forming a Ca–Sn perovskite structure. Nevertheless, it was also confirmed that high structural stability leads to a lower oxygen transfer rate compared to other oxygen carriers, that is, a relatively late reduction reaction completion time. In this study, in order to improve the oxygen transfer rate in the reduction reaction of Ca–Sn oxygen carriers, it was confirmed whether it was actually improved by partially replacing Co and Ce at the Ca site and whether it was applicable as oxygen carriers. It was confirmed that the substances that partially substituted Ce did not improve the oxygen transfer rate, and at the same time, the oxygen transfer capacity was partially reduced compared to CaSnO₃. However, Ca_0.9Co_0.1SnO₃ reduced the reduction reaction time by 20% compared to CaSnO₃. These findings suggest that Co is a promising candidate for improving the oxygen transfer rate of CaSnO₃-based oxygen carriers in CLC processes.