Ca/Cu Co‐doped SmFeO₃ as a Fuel Electrode Material for Direct Electrolysis of CO₂ in SOECs▴

Abstract

The electrochemical conversion of CO 2 to CO by using solid oxide electrolysis cell (SOEC) is an attractive technology for sustainable utilization of greenhouse gas to chemicals. In this work, Ca and/or Cu doped SmFeO 3 perovskite materials in the form of Sm 1-x Ca x Fe 1-y Cu y O 3-d (x = 0, y = 0; x = 0.1, y = 0; x = 0, y = 0.1; x = 0.1, y = 0.1) are evaluated as SOEC fuel electrode for direct electrolysis of CO 2. The Ca and Cu co-doped sample Sm 0.9 Ca 0.1 Fe 0.9 Cu 0.1 O 3-d (SCFCO) presents the highest electrical conductivity value of 15.18 S cm-1 among all of the samples under CO 2 atmosphere at 700°C. The electrochemical impedance spectroscopy analysis reveals that the CO 2 dissociative adsorption and charge transfer of Ca and Cu co-doped fuel electrode are significantly enhanced, resulting in the greatly decrease in polarization resistance compared with that of the undoped sample. The current density of an electrolyte-supported single cell with the SCFCO fuel electrode reaches as high as 1.20 A cm-2 at the applied voltage of 1.5 V and 800°C, which is 60% higher than that of the SmFeO 3-d fuel electrode. Furthermore, the cell shows an impressive stability for the durability test, indicating the excellent electrocatalysis performance and coking tolerance of SCFCO as a promising fuel electrode material for direct electrolysis of CO 2 .