Enhancing CO2 catalytic activation and direct electroreduction on in-situ exsolved Fe/MnOx nanoparticles from (Pr,Ba)2Mn2-yFeyO5+δ layered perovskites for SOEC cathodes

Perovskite-based oxides with exsolved nanoscale transition metal particles are promising cathode materials for direct electrocatalytic reduction of CO2 in the conversion from electrical power to chemical energy through solid oxide electrolysis cells (SOECs). In this paper, a facile method for the in-situ growth of Fe/MnO2 nanoparticles from double-layered perovskite (Pr,Ba)(2)Mn2-yFeyO5+delta substrate was developed and the mechanism of enhanced CO2 catalytic activation was studied by combined experimental characterization and first-principle calculations. We have showed that introducing A-site deficiencies in (Pr,Ba)(2)Mn1-xFexO3+delta can promote in-situ exsolution of Fe from a nonspontaneous process to a spontaneous one thermodynamically. The exsolved Fe particles exhibit significantly enhancement effect, contributing to a highly catalytic performance of direct CO2 electrolysis (638 mA/cm(2) current density under 1.60 V). Such an enhancement is attributed to the promotion of CO2 chemical adsorption, as well as the facilitation of electron transfer from the exsolved nano-particles to CO2.