Pd-Doped Perovskite Oxides with Phase Transition and Bimetallic Nanocatalyst Exsolution to Achieve Highly Active Bifunctional Fuel Electrodes for Reversible Solid Oxide Electrochemical Cells

Abstract

The reducibility of B-site elements in perovskite (ABO3) structures is one of the important factors that accelerate the in-situ exsolution of metallic nanocatalysts. Herein, a highly catalytically active and durable Pd-doped perovskite-based anode material (La0.6Sr0.4Co0.15Fe0.8-xPdxO3-\U0001d6ff (LSCFP)) was developed for reversible SOCs. Under fuel electrode conditions, the LSCFP material is fully transformed into a stable Ruddlesden-Popper phase decorated with bimetallic Co-Fe nanocatalysts. Highly reducible Pd doping in the perovskite lattice effectively reduces the energy barrier for exsolution and formation of bimetallic catalysts on the electrode surface and promote phase transformation into the stable Ruddlesden-Popper-phase in the reducing atmosphere. The SOC with LSCFP fuel electrode yielded outstanding performances in both fuel cell and electrolysis cell modes at 850 °C, with remarkable reversible-cyclic stability. These results indicate that the novel LSCFP, which can simultaneously perform phase transition and bimetal exsolution under reducing conditions, is a very promising candidate as a bifunctional fuel electrode for reversible SOCs.