Enhanced Carbon Dioxide Electrolysis in Zr-Doped Ceria

In solid oxide electrolysis cells (SOECs), the ionic conductivity of the electrode significantly affects the polarization resistance. Therefore, enhancing the ionic conductivity can effectively optimize the performance. In this study, we select cerium oxide, which is known for its excellent redox properties and ability to disperse metal nanoparticles, and we incorporated Zr ions to significantly improve its ionic conductivity. The experimental results indicate that the cathode polarization resistance of a symmetric cell using Ce0.85Zr0.15O2 cathode material is 0.085 Ω cm–2 at 850 °C and 1.8 V. Furthermore, the Ce0.85Zr0.15O2 cathode exhibits a current density of 0.78 A cm–2, which is markedly higher than that of the CeO2 SOEC (0.45 A cm–2). The Ce0.85Zr0.15O2 cathode also achieves a CO yield of 5.4 mL cm–2 min–1, which is considerably higher than that of the pure CeO2 cathode. Incorporating Zr ions into CeO2 enhances the ionic conductivity, reduces the cathode polarization resistance, and improves the electrochemical performance and catalytic efficiency of SOECs. Thus, this study demonstrates the effectiveness of Zr ion doping in enhancing the ionic conductivity of cerium oxide.