Oxygen adsorption capability and electrochemical properties induced by oxygen vacancies in cerium-doped LaFeO3 perovskite oxide

The effect of Ce doping on the electrochemical properties of LaFeO3 perovskite oxides was investigated in terms of the oxygen adsorption capability and polarization resistance. The Ce-doped LaFeO3 perovskite oxide had a single perovskite phase with an orthorhombic structure. The presence of oxygen vacancies was confirmed by EPR spectra and O 1 s core-level spectra. An O2 temperature-programmed desorption profile demonstrated an increase in the quantity of surface-active oxygen species, with LCFO5 exhibiting the highest oxygen adsorption capability. The area-specific resistance gradually decreased with the cerium doping from 11.36 Ωcm2 (LFO) to 4.65 Ω cm2 (LCFO5). A notable decrease of 68 % was confirmed in the polarization resistance related to the mass transfer, from 7.66 Ωcm2 (LFO) to 2.44 Ωcm2 (LCFO5). This significant decrease indicates an enhanced oxygen reduction reaction activity, which is attributed to the accelerated oxygen adsorption reaction.