Surface Reconstruction of La<sub>2</sub>CuO<sub>4</sub> during the Electrochemical Reduction of Carbon Dioxide to Ethylene and Its Benefits for Enhanced Performance
Yuchen Sha, Jaka Sunarso, Ngie Hing Wong, Yuxing Gu, Xinhao Wu, Yu Li, Ran Ran, Wei Zhou, Zongping Shao
Abstract
Electrochemical reduction (ECR) of CO 2 to C 2 H 4 has a potential key role in realizing the carbon neutral future, which ultimately relies on the availability of an efficient electrocatalyst that can exhibit a high Faradaic efficiency (FE) for C 2 H 4 production and robust, long-term operational stability. Here, for the first time, we report that upon applying reductive potential and electrolyte to the benchmark La 2 CuO 4 catalyst, surface reconstruction occurred, i.e., the appearance of a distinctive phase evolution process over time, which was successfully monitored using ex situ powder XRD and operando Mott–Schottky (M–S) measurements of La 2 CuO 4 samples that were soaked into the electrolyte and subjected to CO 2 -ECR for different durations. At the end of such a reconstruction process, an outermost layer consisting of lanthanum carbonate, a thin outer layer made of an amorphous Cu + material formed over the core bulk La 2 CuO 4, as confirmed by various characterization techniques, which resulted in the redistribution of interfacial electrons and subsequent formation of electron-rich and electron-deficient interfaces. This contributed to the enhancement in FE for C 2 H 4, reaching as much as 58.7%. Such surface reconstruction-induced electronic structure tuning gives new explanations for the superior catalytic performance of La 2 CuO 4 perovskite and also provides a new pathway to advance CO 2 -ECR technology.