Air separation via two-step solar thermochemical cycles based on SrFeO and (Ba,La)SrFeO perovskite reduction/oxidation reactions to produce N: rate limiting mechanism(s) determination.

Two-step solar thermochemical cycles based on reversible reactions of SrFeO and (Ba,La)SrFeO perovskites were considered for air separation. The cycle steps encompass (1) the thermal reduction of SrFeO or (Ba,La)SrFeO perovskites driven by concentrated solar irradiation and (2) oxidation in air to remove O and produce N. Rate limiting mechanisms were examined for both reactions using a combination of isothermal and non-isothermal thermogravimetry for temperature-swings between 673 and 1373 K, heating rates of 10, 20, and 50 K min, and O pressure-swings between 20% O/Ar and 100% Ar at atmospheric pressure.

An A- and B-Site Substitutional Study of SrFeO Perovskites for Solar Thermochemical Air Separation.

An A‑ and B‑site substitutional study of SrFeO perovskites (A'AB'BO, where A = Sr and B = Fe) was performed for a two‑step solar thermochemical air separation cycle. The cycle steps encompass (1) the thermal reduction of A'SrB'FeO driven by concentrated solar irradiation and (2) the oxidation of A'SrB'FeO in air to remove O, leaving N. The oxidized A'SrB'FeO is recycled back to the first step to complete the cycle, resulting in the separation of N from air and concentrated solar irradiation.