Functionalizing Robust (La,Sr)(Cr,Fe,Ni)O3 Mixed Ionic-Electronic Conducting Electrocatalysts through Bimetallic FeNi-Based Exsolution for Solid Oxide Electrolysis

Solid oxide electrolysis cells (SOECs) are a promising alternative for highly efficient syngas production due to their ability to couple with renewable electricity (e.g. solar or wind power) and utilization of waste heat from industrial processes. To unlock their full potential a primary challenge is the development of redox stable, coking tolerant and catalytically active mixed ionic and electronic conducting (MIEC) materials. Here, we have functionalized a robust lanthanum strontium iron chromate by introducing both A-site deficiency to increase the number of oxygen vacancies and surface exchange kinetics, as well as Ni-doping at the B-site to boost catalytic properties by exsolving FeNi-based alloy nanoparticles. The morphological analysis revealed the high thermal stability of the host perovskite and the successful decoration of its surface with an Fe-rich, FeNi alloy as identified by the HRTEM analysis after reduction at 900 °C for 12 h. The physicochemical characterizations revealed a significant enhancement of the electrocatalytic properties of the modified samples that resulted in an >40% decrease in electrode polarization resistance in CO2/H2O co-electrolysis conditions. Our approach shows that simple yet rational modifications of highly stable perovskite oxides in combination with nano-engineering through exsolution could have a significant effect for advancing MIEC electrodes in SOECs.