Lanthanum Manganite Perovskites with Ca/Sr A‐site and Al B‐site Doping as Effective Oxygen Exchange Materials for Solar Thermochemical Fuel Production

Perovskite oxides have recently been proposed as promising redox intermediates for solar thermochemical splitting of H 2 O and CO 2 , offering the benefit of significantly reduced operating temperatures. We present a systematic experimental screening of doped lanthanum manganites within the composition space La 1− x (Ca,Sr) x Mn 1− y Al y O 3 and identify several promising redox materials. In particular, La 0.6 Sr 0.4 Mn 0.6 Al 0.4 O 3 and La 0.6 Ca 0.4 Mn 0.6 Al 0.4 O 3 boast a five‐ to thirteen‐fold improvement in the reduction extent compared to the state‐of‐the‐art material CeO 2 in the temperature range 1200–1400 °C. The materials are shown to be capable of splitting CO 2 into CO fuel when isothermally cycled between low‐ p O 2 and high‐ p CO 2 environments at 1240 °C and to approach full reoxidation in CO 2 with temperature swings as low as 200 °C, with mass‐specific fuel yields up to ten times that of CeO 2 . The underlying material thermodynamics are investigated and used to explain the favorable redox behavior.