New Triclinic Perovskite-Type Oxide Ba5CaFe4O12for Low-Temperature Operated Chemical Looping Air Separation

We present the discovery of Ba5CaFe4O12, a new iron-based oxide with remarkable properties as a low-temperature driven oxygen storage material (OSM). OSMs, which exhibit selective and rapid oxygen intake and release capabilities, have attracted considerable attention in chemical looping technologies. Specifically, chemical looping air separation (CLAS) has the potential to revolutionize oxygen production as it is one of the most crucial industrial gases. However, the challenge lies in utilizing OSMs for energy-efficient CLAS at lower temperatures. Ba5CaFe4O12, a cost-competitive material, possesses an unprecedented 5-fold perovskite-type A5B5O15−δstructure, where both Fe and Ca occupy the Bsites. This distinctive structure enables excellent oxygen intake/release properties below 400 °C. This oxide demonstrates the theoretical daily oxygen production rate of 2.41 mO23kgOSM–1at 370 °C, surpassing the performance of the previously reported material, Sr0.76Ca0.24FeO3−δ(0.81 mO23kgOSM–1at 550 °C). This discovery holds great potential for reducing costs and enhancing the energy efficiency in CLAS.