Barium carbonate nanoparticle as high temperature oxygen reduction catalyst for solid oxide fuel cell

•BaCO3 nanoparticles can greatly enhance high-temperature oxygen reduction.•It could greatly reduce the low frequency resistance as well as increase oxygen surface exchange coefficient.•Its catalytic improving factor is higher than those reported for Pd, Rh and Pt.

BaCO3 nanoparticles are demonstrated as outstanding electrocatalysts to enhance the high temperature oxygen reduction reaction (ORR) in solid oxide fuel cells (SOFCs). BaCO3 nanoparticles are formed from thermal decomposition of barium acetate, Ba(Ac)2 infiltrated to porous cathode skeleton and shows good chemical compatibility with cathode materials. BaCO3 nanoparticles can greatly reduce the area specific resistance (ASR) of typical SOFC cathode materials, including La0.8Sr0.2FeO3 -δ (LSF), La0.6Sr0.4Co0.2Fe0.8O3 -δ (LSCF) and La0.8Sr0.2MnO3 -δ (LSM). For example at 700 °C, ASR for LSF on yttria-stabilized zirconia (YSZ) electrolyte decreases from 2.95 Ω cm2 to 0.77 Ω cm2 when 12.9 wt.% BaCO3 nanoparticles are deposited on the surface of the porous LSF electrode. Impedance spectra analysis shows that the decrease in ASR mainly comes from the reduction of the low frequency resistance. Furthermore, BaCO3 nanoparticles are found to greatly enhance the oxygen chemical exchange coefficient. Most importantly, it has been found that the catalytic activity of BaCO3 nanoparticles is even higher than those of the precious metals such as Pd, Rh, Pt and Ag, infiltrated into LSF, LSCF and LSM electrodes supported on YSZ electrolytes.