Boosting CO 2 Electrolysis via a Metal-Free F/Gd Co-doped CeO 2 Cathode for Solid Oxide Electrolysis Cells

Abstract

As an efficient device for energy conversion, solid oxide electrolysis cells (SOECs) can utilize renewable energy to efficiently convert CO2 into CO, realizing both CO2 resource utilization and chemical storage of renewable energy. Traditional nickel-yttria-stabilized-zirconia (Ni-YSZ) fuel electrodes face issues such as Ni agglomeration and carbon deposition in practical applications. In this study, pure ceramic fuel electrode of fluorine and gadolinium co-doped CeO2 with mixed ionic-electronic conducting and enhanced electrocatalytic activity is investigated. The results reveal that F and Gd co-doped CeO2 exhibits enhanced catalytic activity and CO2 adsorption capacity. The cell with F0.1Gd0.1Ce0.9O2−δ fuel electrode can achieve a maximum electrolysis current density of 1.45 A·cm−2 at 1.5 V at 850 °C, with Rp of 0.023 Ω·cm2. Furthermore, the cell exhibits excellent durability for 200 h at 0.5 A·cm−2 without significant degradation. This work shows that F and Gd co-doped CeO2 provides a feasible way for the development of nickel-free SOEC cathodes.