In situ growth of copper-iron bimetallic nanoparticles in A-site deficient Sr2Fe1.5Mo0.5O6-δ as an active anode material for solid oxide fuel cells

The design of active anode materials with abundant active sites for fuel oxidation reaction is highly desirable. In-situ exsolution of nanoparticles from perovskite oxides is an effective approach to maintain its nanoscale dimensions and provide efficient active sites. Herein, a promising anode material decorated with copper-iron bimetallic nanoparticles is prepared by in-situ exsolution from A-site deficient Sr1.9Fe1.5Mo0.5−xCuxO6-δ double perovskite. With the doping of Cu, the agglomeration of iron nanoparticles is highly inhibited under reducing environment and copper-iron bimetallic nanoparticles can be uniformly formed. Through high temperature reduction, Sr1.9Fe1.5Mo0.5O6-δ substrate is transferred to heterostructure consisting of a Ruddlesden-Popper phase (Sr3FeMoO6.5) and a perovskite phase. The in-situ exsolved copper-iron bimetallic nanoparticles on the heterostructure can provide abundant active sites for fuel oxidation and lead to an improvement of polarization resistance from 0.41 Ω·cm2 to 0.22 Ω·cm2 at 800 °C under H2. In addition, the maximum power density is increased to 574 mW cm−2, which is about 37% higher than that of Sr1.9Fe1.5Mo0.5O6-δ. The present study provides a potential strategy for developing efficient anode materials for solid oxide fuel cells.