Surface Exchange Reaction of Mixed Conductive LaCaFeO during Oxygen Evolution and Incorporation as Traced by Operando X-ray Photoelectron Spectroscopy.

High oxygen permeability of mixed conductive LaCaFeO (LCF) is applicable to pure oxygen gas generators and cathodes for solid oxide fuel cells, etc.; however, lower surface exchange reactions at temperatures below 800 °C reduce permeability. To understand the microscopic surface reaction mechanism, operando soft X-ray photoelectron spectroscopy of an LCF film surface was conducted during the evolution and incorporation of oxygen.