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Perovskite structured mixed metal oxides (ABO 3 ) are one promising category of redox materials widely investigated for applications in various sustainable processes. In this study, we monitored the compositional and surface structural evolution of CaMnO 3 under redox conditions at selected temperatures. The redox efficiency and stability of CaMnO 3 was found to be temperature dependent. Despite enhanced sintering resistance and phase stability at 600 8C, the amount of oxygen release/uptake was low. At 750 8C, phase changes were found to diminish the redox efficiency in the long run. In contrast, at higher temperatures (900 8C) a stable oxygen uptake/release capacity was observed despite significant sintering and the associated structural and phase changes. The present study indicates that material composition and temperature determine the redox chemistry of CaMnO 3 perovskite oxides. Interestingly, no noticeable amount of surface carbon deposition was detected under any stages of operation for this material.

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