Surface regulating of copper-iron nanoparticles bimetallic exsolution for enhanced performance and durability of double perovskite anode in solid oxide fuel cells

The metallic exsolved ceramic anode for Solid oxide fuel cells (SOFCs) has garnered immense attention owing to its abundant active sites and high catalytic efficacy. However, the performance and durability of nanoparticle decorated ceramic anodes are still hindered by the morphology and size of exsolved nanoparticles, but there are few studies on the specific dissolution rules and conditions. Here, the Cu element is doped into high-performance Sr_1.9Fe_1.5Mo_0.5O_6-δ materials to study the exsolution law of nanoparticles and the change of nanomorphology in the reduced state. Sr_1.9Fe_1.5Mo_0.4Cu_0.1O_6-δ (SFMC0.1), used as an anode for solid oxide fuel cells, can evolve into high-performance composite phases composed of perovskite, Ruddlesden-Popper phase, and copper-iron bimetallic nanoparticles under the condition of 800 °C wet hydrogen. At the same time, the reduction treatment containing water vapor will make the Fe nanoparticles exhibit rare whisker-like nanoparticles, and copper will be wrapped on the iron nanoparticles to form a core–shell structure, which effectively inhibits the high-temperature agglomeration of Fe nanoparticles. When used as an anode in an electrolyte-supported SOFC, it exhibits commendable performance and good durability at 800 °C with a maximum power density increasing from 0.63 to 1.2 W cm⁻² (H₂ fuel) over reduction time due to the influence of phase transition and exsolution morphology. Therefore, the reduction in H₂O environment and the low temperature is an effective method to control the whisker-like Fe nanoparticles to improve the catalytic performance, and the doping of Cu can ensure the formation of Cu-coated core–shell structure to inhibit the agglomeration of nanoparticles.