Ce<sup>4+</sup>-Doped CuO Mesoporous Nanosheets for CO<sub>2</sub> Electroreduction to C<sub>2</sub>H<sub>6</sub> with High Selectivity under a Wide Potential Window in a Flow Cell
Nannan Zhu, Xingyue Zhang, Peng Wang, Nannan Chen, Jiahui Zhu, Xinyue Zheng, Zheng Chen, Tian Sheng, Zhengcui Wu
Abstract
CO 2 electrocatalytic reduction (CO 2 ER) to multiple carbonous products is a valuably sustainable way to obtain fuels and chemicals. However, its practical application is still hindered by low selectivity and activity under large current density. A flow cell enables CO 2 ER to operate at high current densities by mitigating the CO 2 mass transport limitation issue. Here, we report Ce 4+ -doped CuO mesoporous nanosheets affording high selectivity and activity toward CO 2 ER to C 2 H 6 in a flow cell. Ce 4+ doping induces oxygen vacancies and modulates the electron distribution of CuO, which enhances the adsorption intensity and coverage of a *CO intermediate for further C–C coupling to finally produce C 2 H 6 . Moreover, Ce 4+ doping can well protect Cu 2+ species from being reduced during CO 2 ER, which guarantees high selectivity and stability for C 2 H 6 generation. As a result, the optimal Ce 0.03 Cu 0.97 O 0.83 exhibits large partial current densities of 55.3 ± 1.6–235.5 ± 4.3 mA cm –2 with Faradaic efficiencies over 50% for ethane under a wide potential window of −0.5 to −0.9 V in a flow cell. This work clarifies that the CuO nanostructure doped with lanthanide metal ions can modulate the reaction pathway of CO 2 ER to C 2 H 6 in a flow cell.