Highly oxygen reduction activity and CO2 resistance of Fe-based cathode electrocatalysts for solid oxide fuel cells

Abstract

The insufficient electrocatalytic activity and CO2 resistance hinder the application of cathode material for solid oxide fuel cells (SOFCs). In this study, we introduce a series of Pr-doped perovskite Bi0.8–xPrxCa0.2FeO3–δ (BPCFx, x=0, 0.10, 0.15, 0.20) as candidate cathode materials, with a focus on its phase structure, oxygen desorption ability, catalytic activity, and electrochemical reduction kinetics. Among all the components, the Bi0.6Pr0.2Ca0.2FeO3–δ (BPCF0.20) catalyst shows impressive oxygen reduction reaction (ORR) activity, with a low polarization resistance of 0.06 Ω cm2 at 700 °C and peak power density of 810 mW cm−2 at 800 °C. Moreover, the BPCF0.20 cathode shows outstanding CO2 resistance in different CO2 concentrations (1% ∼ 10%) due to the larger average bond energy and higher relative acidity of Bi, Pr, and Fe ions. These findings demonstrate that BPCFx are advanced cathode electrocatalysts for SOFCs.