Enhancing the hydrogen tolerance of La_0.6Ca_0.4Co_0.2Fe_0.8O_3–d oxygen transport membranes with the substitution of 10 % Mn at the B site for plasma assisted CO₂ conversion

The tendency of mixed ionic electronic conducting (MIEC) materials to be highly selective towards oxygen allows for their use as oxygen transport membranes (OTMs). To be used as OTMs in plasma assisted CO₂ conversion and H₂ utilisation applications, requires high oxygen permeability, structural stability against reducing atmospheres (such as CO₂, CO, H₂, etc.) and suitable mechanical properties. La_0.6Ca_0.4Co_1–xFe_xO_3–d (LCCF) has already shown excellent tolerance against CO₂ and recently, in our previous work, its specific variant, La_0.6Ca_0.4Co_0.2Fe_0.8O_3–d (LCCF_6428) showcased hydrogen tolerance for upto 25 hours at 600 °C. In this work, we aim to further improve the hydrogen tolerance of LCCF_6428 by the introduction of strong Mn⁴⁺-O bonds into the material structure. To achieve this, 10 % Fe was substituted with manganese (Mn) at the B site of LCCF_6428. The resulting composition La_0.6Ca_0.4Co_0.2Fe_0.7Mn_0.1O_3–d (LCCF_64271) was chosen and synthesized with ultrasonic spray synthesis (USS). The presence of strong Mn⁴⁺-O bonds led to a two-fold increase in the hydrogen tolerance of the membrane material with respect to LCCF_6428 with a slight 5 % decrease in oxygen permeability.