Exsolved Alloy Nanoparticles Decorated Ruddlesden-Popper Perovskite as Sulfur-Tolerant Anodes for Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) based on Ni-based cermet anodes suffer from severe sulfur poisoning when operated on H2S-containing fuels (<10 ppm of H2S). Thus, the development of alternative anodes is of great importance. Perovskite oxides with Ruddlesden-Popper (RP) structure show great potential as sulfur-tolerant anodes in SOFCs; however, the electrocatalytic activity has not been satisfied until now. Herein, we propose a design strategy for the fabrication of alloy nanoparticles decorated RP perovskite through in situ exsolution using La0.6Sr0.4Ni0.2Mn0.2Fe0.6O3-δ and La0.6Sr0.4Co0.2Mn0.2Fe0.6O3-δ as the precursors. The formation of FeNi/FeCo alloy nanoparticles and their atomic ratios (Fe3Co2, Fe3Ni2) is confirmed. The Fe3Co2/La1.2Sr0.8Mn0.4Fe0.6O4-δ (RP-LSMF) anode displayed superior electro-activity for H2 oxidation and excellent sulfur resistance to those of Fe3Ni2/RP-LSMF due to the higher amount of exsolved nanoparticles and the stronger interaction between exsolved nanoparticles and perovskite host. An electrolyte-supported SOFC with Fe3Co2/RP-LSMF anode delivers high peak power densities of 632 and 566 mW cm-2 when operated on H2 and 200 ppm of H2S-H2 at 800 °C, respectively. Furthermore, the cell with Fe3Co2/RP-LSMF anode delivers a superior operational stability to that of Fe3Ni2/RP-LSMF in 200 ppm of H2S-H2 fuel. This work can present some useful guidance for the rational design of sulfur-resistant RP perovskite-based anodes for SOFCs.