New Triclinic Perovskite-Type Oxide Ba 5 CaFe 4 O 12 for Low-Temperature Operated Chemical Looping Air Separation.

We present the discovery of Ba 5 CaFe 4 O 12 , 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. Ba 5 CaFe 4 O 12 , a cost-competitive material, possesses an unprecedented 5-fold perovskite-type A 5 B 5 O 15-δ structure, where both Fe and Ca occupy the B sites. This distinctive structure enables excellent oxygen intake/release properties below 400 °C. This oxide demonstrates the theoretical daily oxygen production rate of 2.41 m O2 3 kg OSM -1 at 370 °C, surpassing the performance of the previously reported material, Sr 0.76 Ca 0.24 FeO 3-δ (0.81 m O2 3 kg OSM -1 at 550 °C). This discovery holds great potential for reducing costs and enhancing the energy efficiency in CLAS.