High temperature CO2 electrolysis on La(Sr)Fe(Mn)O₃ oxide cathode by using LaGaO₃ based electrolyte

Electrochemical conversion of carbon dioxide to carbon monoxide (CO₂ → CO) is a potential useful step in the desirable transformation of the greenhouse gas to fuels or useful chemicals. In this study, the electrochemical conversion of CO₂ to CO on oxide cathode was studied in a solid oxide electrolysis cell (SOEC) by using a LaGaO3-based electrolyte (La_0.9Sr_0.1Ga_0.8Mg_0.2O₃, LSGM) at elevated temperature (i.e. 973 - 1173 K), which is a good candidate as electrolyte for electrolysis cell because of the high oxide ion conductivity at intermediate temperatures. It was found that a LaFeO3-d-based perovskite material as cathode (La_0.6Sr_0.4Fe_0.8Mn_0.2O_3-δ, LSFM6482) shows much higher activity for CO₂ electrolysis among the examined oxide and a current density of CO₂ electrolysis is achieved with a value of 0.52 A/cm² at 1.6 V and 1173 K. Doping Sr and Mn to LaFeO₃ is highly effective for increasing the cathode activity for CO₂ electrolysis under the feed gas condition, which is consisted of 50%CO₂, 1%CO, and 49%Ar. Porous structure with fine particle (0.5 μm) and main phase stability of LSFM6482 cathode can be sustained under CO₂ electrolysis condition.