In situ self-reconstructed nanoparticle-coated cathode and anode by nitric acid etching for symmetric solid oxide fuel cells

In this study, we developed an innovative strategy to fabricate highly active cathode and anode materials by acid etching perovskite oxide (ABO3) powder. (CoxFe1-x)3O4 nanoparticles were exsoluted in situ on an etched Pr0.2Sr0.8Co0.2Fe0.8O3-δ (P0.2SCF) catalyst to reconstruct heterojunctions in air. As a result, the exsolution of (CoxFe1-x)3O4 nanoparticles on the P0.2SCF surface led to the formation of perovskite-spinel interfaces in the cathode, and the generation of CoFe alloy and CoO nanoparticles embedded on the surface of the anode in 5 % H2. Two new composite catalysts modified with nanoparticles on the P0.2SCF skeleton were simultaneously prepared through the in situ exsolution of perovskite. At 850 °C, the polarization resistance values of the anode and cathode decreased by 37 % and 57 %, respectively. Furthermore, in a single cell with LSGM electrolyte and P0.2SCF-30-GDC symmetrical electrodes, we achieved a maximum power density of 692 mW/cm2 at 850 °C under wet H2 conditions, demonstrating good electrochemical output performance. The proposed catalyst design, which employed acid etching, was not only suitable for the optimization of symmetrical solid oxide fuel cell (SSOFC) electrodes, but also for the application in other types of catalysis, providing the potential for improving the electro-catalytic activity of perovskite electrodes.