Improving the Performance for Direct Electrolysis of CO2 in Solid Oxide Electrolysis Cell with Sr1.9Fe1.5Mo0.5 O6 - δ Electrode Via Infiltration of Pr6O11 Nanoparticles

Abstract

High temperature direct CO2 electrolysis based on solid oxide electrolysis cell (CO2-SOEC) is a promising technology to convert carbon dioxide to carbon monoxide with a high current density and Faradaic efficiency. The exploration for suitable cathodes with desirable catalytic activity is a grand challenge for the development of CO2-SOEC. Sr2Fe1.5Mo0.5O6 - δ is often used as the cathode material for SOEC, but suffers from insufficient activity for CO2 reduction reaction (CO2RR). In this work, nanoscale Pr6O11 was infiltrated into the Sr1.9Fe1.5Mo0.5O6 - δ (SFM) electrode to promote the CO2RR performance in SOEC. The optimal loading of Pr6O11 is systematically investigated. At 800°C, the current density of the Pr6O11 infiltrated SFM cathode with a Pr6O11 loading of 13.4wt.% reaches 1.58 A/cm2 at 1.5V, which is 2.5 times higher than that of SFM cathode (0.63 A/cm2) at the same operating conditions. X-ray photoelectron spectroscopy characterization and temperature-programmed desorption of CO2 measurements indicate that the adsorption and desorption ability of CO2 of SFM cathode are improved by the infiltration of Pr6O11. Further, the polarization resistance of SFM cathode has significantly decreased with the infiltrated Pr6O11. These results demonstrate that the infiltration of Pr6O11 is a promising approach for increasing CO2RR activity. Acknowledgements Financial support from the U.S. Department of Energy (DE-EE0009427) and NASA EPSCoR (Grant # 80NSSC20M0233) is greatly appreciated.