CaCoxZr1−xO3−δ Perovskites as Oxygen‐Selective Sorbents for Air Separation

ABO3−δ perovskites are ideal for high‐temperature thermochemical air separation for oxygen production because their oxygen nonstoichiometry δ can be varied in response to changes in temperature and oxygen partial pressure [pO2 ]. Herein, the outstanding oxygen‐sorption performance of CaCoxZr1−xO3−δ perovskites and their potential application as oxygen‐selective sorbents for air separation is reported. In situ thermal X‐ray diffraction was used to study the materials’ structural changes in response to temperature variations in air and inert atmosphere. Temperature‐programmed reduction was employed to elucidate the relationship between perovskite composition and redox property. O2 sorption performance was evaluated by isothermal analyses at various temperature and pO2 along with long‐term absorption–desorption cycle tests. The high oxygen‐sorption capacity was mainly attributed to Co at B‐site, whereas partial substitution of Co by Zr enhanced the structural crystallinity and thermal stability of the perovskite. A stable oxygen production of 2.87 wt % was observed at 900 °C during 5 min‐sorption cycles for 100 cycles. Take a deep breath: CaCoxZr1−xO3−δ perovskites are explored as potential candidates for thermochemical air separation for O2 production. By varying the ratio of Co/Zr ions at the B‐site, the oxygen‐sorption capacity, crystallinity, and thermal stability can all be improved. The proposed perovskites can produce a stable performance over extended periods of time.