Limited oxygen surface exchange for oxygen transport membrane (OTM) material in humid atmosphere, correlated with Sr surface segregation identified using isotopic exchange and mass spectrometry.

Mixed ionic and electronic conducting (MIEC) perovskite oxides (ABO 3 ) have a substantial role in carbon-neutral clean energy conversion and storage technologies. Owing to their favorable catalytic properties, high ionic and electronic conductivity, and chemical and redox stability, MIEC perovskite oxides are promising electrode materials in multiple applications, such as solid oxide fuel/ electrolysis cells, oxygen transport membranes, metal−air batteries, electrochemical sensors, and electrocatalysts for water splitting. Here, taking (La 0.8 Sr 0.2 ) 0.95 Cr 0.5 Fe 0.5 O 3−δ (LSCrF8255) as a model MIEC perovskite oxide, we demonstrate that the oxygen mass transport properties are significantly enhanced under a humid reducing water vapor environment (pO 2 < 1 mbar, pH 2 O = 30 mbar) by up to 4 orders of magnitude compared to those measured under dry (pO 2 = 200 mbar) and wet (pO 2 = 200 mbar, pH 2 O = 30 mbar) oxygen atmospheres. A 0.8 eV decrease in the activation energy for oxygen bulk diffusion was also found under water vapor, and a decrease in activation energy of 0.7 eV for water surface exchange compared to oxygen surface exchange was found. The mechanisms underpinning these enhancements were explored. Furthermore, LSCrF8255 has also exhibited a consistent surface composition evolution regarding Sr segregation and phase separation and an excellent bulk stability under both oxidizing and reducing environments at elevated temperatures.

The effect of operating conditions on the surface composition and evolution of (La0.8Sr0.2)0.95Cr0.5Fe0.5O3-δ (LSCrF8255) as a model perovskite oxide was investigated. LSCrF8255 pellets were annealed under dry oxygen (pO2 =...

The understanding of protonic defect transport mechanism in Ba(Ce,Zr)O3 perovskites oxides and its proper temperature range of conductivity are fundamentals for materials design and their technological applications as electrolyte for...

A channel prediction scheme based on federated learning is proposed to achieve channel pre-compensation for a low-cost design of FSO communication system. The proposed scheme is demonstrated effective in simplifying system structural and operational cost.