Fe-decorated on Sm-doped CeO2 as cathodes for high-temperature CO2 electrolysis in solid oxide electrolysis cells

Electrocatalytic CO 2 reduction in solid oxide electrolysis cells (SOECs) can simultaneously convert CO 2 to valuable chemicals or fuels by integrating with renewable energy so as to alleviate the greenhouse effects and energy crisis. Cerium oxide (CeO 2 ) with high redox stability and catalytic activity toward CO 2 reduction is considered a promising SOEC cathode. However, CeO 2 is rarely directly employed as cathodes due to its unsatisfactory electrical properties. Suitable modification of CeO 2 becomes essential to improve its electrocatalytic activity . Herein, Fe-decorated on Sm-doped CeO 2 via a simple mechanical milling process was employed as cathodes for high-temperature CO 2 electrolysis in SOEC. The addition of Fe species on Sm-doped CeO 2 can greatly enhance the CO 2 electrolysis efficiency, mainly attributing to the increased catalytic active sites, electronic pairs, and oxygen vacancy concentrations, which facilitated the CO 2 adsorption and dissociation as well as the electron-ion transportation. The 1.0 wt.% Fe-decoreated on Sm-doped CeO 2 showed the highest current density of 0.57 A cm −2 at 1.9 V under 800 °C. Moreover, the co-existence of doped and surface coated Fe species on Sm-doped CeO 2 with moderate oxygen vacancies and adequate electronic transportation paths facilitate the high-temperature CO 2 electrolysis.