In situ exsolved FeNi3 nanoparticles on nickel doped Sr2Fe1.5Mo0.5O6−δ perovskite for efficient electrochemical CO2 reduction reaction

Abstract

Solid oxide electrolysis cells (SOECs) have attracted increasing attention as a promising device for the electrochemical CO₂ reduction reaction (CO₂RR) due to their high efficiency and fast kinetics. Exploring active cathode catalysts for the CO₂RR is highly desirable for the research and development of SOECs. Herein, in situ exsolved FeNi₃ nanoparticles on a Sr₂Fe_1.35Mo_0.45Ni_0.2O_6−δ (SFMN) double perovskite substrate (FeNi₃@SFMN) is developed to efficiently catalyze the CO₂RR in SOECs. The SOEC with the FeNi₃@SFMN–GDC (Gd_0.2Ce_0.8O_1.9) cathode shows a current density of 0.934 A cm⁻² at 1.6 V and 800 °C, as well as high stability and no coke deposition for 40 h at 1.2 V. CO₂-temperature programmed desorption and quasi in situ Fourier-transform infrared spectroscopy measurements verify the intensive adsorption of CO₂ on the FeNi₃@SFMN–GDC cathode. Distribution of relaxation time analysis combined with density functional theory calculations discloses the stimulative activation of CO₂ at the interface between the exsolved FeNi₃ nanoparticles and the SFMN substrate with abundant oxygen vacancies, which improves the CO₂RR performance at the FeNi₃@SFMN–GDC cathode.