Exsolution of Cu nanoparticles in (LaSr)0.9Fe0.9Cu0.1O4 Ruddlesden-Popper oxide as symmetrical electrode for solid oxide cells.

• A highly active layered perovskite LSFCu could be used for symmetrical SOCs as the fuel electrode and the oxygen electrode. • The Cu nanoparticles-decorated LSFCu could be simply prepared by a reducing procedure. • The exsolution of Cu in LSFCu is studied via DFT calculations. In this work, we report a highly active Ruddlesden-Popper oxide as a symmetrical electrode for solid oxide cells through in-situ exsolution strategy. The Cu nanoparticles-decorated (LaSr) 0.9 Fe 0.9 Cu 0.1 O 4 (LSFCu) oxide can be simply fabricated by a reducing procedure. The exsolved mechanism of Cu nanoparticle is investigated by the density functional theory (DFT) method. The calculation demonstrates that oxygen releasing is present more energetic in the rocksalt layers, causing the accelerated kinetics of exsolution. The (1 0 0) surface could be the preferential surface for exsolution where take place because of the lowest surface energy. The LSFCu shows a highly electrocatalytic activity as fuel electrode and oxygen electrode simultaneously toward oxygen reduction reaction (ORR) and fuel oxidation reaction (FOR) respectively. In fuel cell (FC) mode, the peak power densities are 573 mW cm−2 and 396 mW cm−2 at 800 °C using humidified H 2 and CH 4 as fuels, respectively. Moreover, a very high current density of 1.02 A cm−2 can also be accomplished at a voltage of 1.2 V in electrolysis cell (EC) mode, implying that this Ruddlesden-Popper oxide decorated by Cu nanoparticles is highly active as the catalyst for the steam electrolysis in symmetrical solid oxide cells. [ABSTRACT FROM AUTHOR]