In situ exsolution of FeCo alloy nanoparticles for highly efficient CO2 electrolysis

Abstract

In the context of current energy and environmental issues, the treatment and utilization of the greenhouse gas CO₂ has become a significant area of research. Solid oxide electrolytic cells (SOECs) with straightforward and reliable electrode reactions can effectively harness renewable, clean energy sources to transform CO₂ into valuable carbon-containing chemicals. The focus of research in the field of SOEC cathode materials has been on CeO₂ due to its advantageous properties, including its multifunctionality and tunability. In this work, Fe and Co dopants are dissolved and anchored in CeO₂ on the electrode surface using an in situ exsolution approach, resulting in the formation of FeCo alloy nanoparticles. These particles then generate strong interaction forces with the substrate, leading to the formation of rich and stable active sites. The SOEC comprising Ce_0.9(Fe_0.5Co_0.5)_0.1O_2−δ as the symmetric electrode demonstrated a CO yield of 4.2 mL min⁻¹ cm⁻² at 850 °C and 1.8 V, and a Faraday current efficiency of 90.3%. Following 108 hours of operation at 1.4 V, no significant performance degradation is observed, and the microstructure is found to be well maintained.