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

Abstract

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 Sr₂CoMo_1-<i>x</i>Fe_<i>x</i>O_6-δ (<i>x</i> = 0, 0.05, 0.1) double perovskite oxides under a reducing condition at 850 °C. The exsolved nanoparticles from the Sr₂CoMo_0.95Fe_0.05O_6-δ (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 H₂ 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 H₂ and CH₄ at 850 °C, respectively, while maintaining superior stability (∼50 h at 700 °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 H₂ and CO. The findings in this work may provide a new insight for the design of highly active and durable anode catalysts in SOFCs.