Enhanced Anode Performance and Coking Resistance by In Situ Exsolved Multiple-Twinned Co-Fe Nanoparticles for Solid Oxide Fuel Cells

摘要

The broad and large-scale application of solid oxide fuel cells (SOFCs) technology hinges significantly on the development of highly active and robust electrode materials. Here, Ni-free anode materials decorated with metal nanoparticles are synthesized by in situ reduction of Fe-doping Sr2CoMo1-xFexO6-delta (x = 0, 0.05, 0.1) double perovskite oxides under a reducing condition at 850 degrees C. The exsolved nanoparticles from the Sr2CoMo0.95Fe0.05O6-delta (SCMF0.05) lattice are Co-Fe alloys with rich multiple-twinned defects, significantly enhancing the catalytic activity of the SCMF0.05 anode toward the oxidation of H-2 and CH4. The electrolyte-supported single cell with the reuduced SCMF0.05 anode reaches peak power densities as high as 992.9 and 652.3 mW cm(-2) in H-2 and CH4 at 850 degrees C, respectively, while maintaining superior stability (similar to 50 h at 700 degrees C). The reduced SCMF0.05 anode also demonstrates excellent coking resistance in CH4, which can be attributed to the increased oxygen vacancies due to Fe doping and the effective catalysis of multiple-twinned Co-Fe alloy nanoparticles for reforming of CH4 to H-2 and CO. The findings in this work may provide a new insight for the design of highly active and durable anode catalysts in SOFCs.