Copper-Enhanced CO₂ Electroreduction in SOECs

The development of a Co-free and Ni-free electrocatalyst for carbon dioxide electrolysis would be a turning point for the large-scale commercialization of solid-oxide electrolysis cells (CO₂-SOECs). Indeed, the demand for cobalt and nickel is expected to become critical by 2050 due to automotive electrification. Currently, the reference materials for CO₂-SOEC electrodes are perovskite oxides containing Mn or Co (anodes) and Ni-YSZ cermets (cathodes). However, issues need to be addressed, such as structural degradation and/or carbon deposition at the cathode side, especially at high overpotentials. This work designs the 20 mol % replacement of iron by copper in La_0.6Sr_0.4FeO_3-δ as a multipurpose electrode for CO₂-SOECs. La_0.6Sr_0.4Fe_0.8Cu_0.2O_3-δ (LSFCu) is synthesized by the solution combustion method, and iron partial substitution with copper is evaluated by X-ray powder diffraction with Rietveld refinement, X-ray photoelectron spectroscopy, thermogravimetric analyses, and electrical conductivity assessment. LSFCu is tested as the SOEC anode by measuring the area-specific resistance versus T and pO₂. LSFCu structural, electrical, and electrocatalytic properties are also assessed in pure CO₂ for the cathodic application. Finally, the proof of concept of a symmetric LSFCu-based CO₂-SOEC is tested at 850 °C, revealing a current density value at 1.5 V of 1.22 A/cm², which is remarkable when compared to similar Ni- or Co-containing systems.