Fluorine‐Driven Interfacial Reconfiguration for pH‐Universal CO 2 Electrolysis at High Current Densities via Enhanced CO 2 Enrichment and Proton Fee
Yingzheng Zhang, Bo Huang, Huayi Kuang, Wuyi Feng, Fang Zhang, Botao Hu, Zhicheng Zhang, Jiatao Zhang, Chen Chen, Di ZhaoABSTRACT
High‐rate CO 2 electroreduction is challenged by the conflict between sluggish CO 2 activation and hydrogen evolution at high currents, particularly under pH‐universal and dilute CO 2 conditions. In this study, a defective fluorine‐modified bismuth (F‐Bi) with electron‐rich surface was generated by electrochemical reconstruction of fluorine‐doped bismuth oxide (F‐Bi 2 O 3 ), which exhibits a formate/formic acid Faradaic efficiency (FE HCOO − /HCOOH ) approaching 100% at 1800 mA cm −2 under pH‐universal conditions. In a membrane electrode assembly (MEA), F‐Bi delivers a FE HCOO − of 95.2% at 3.6 V and sustains operation for 120 h at a total current of 1 A. It also maintains a FE HCOO − above 95% at 800–1200 mA cm −2 under a dilute CO 2 feed of 15 vol% CO 2 /N 2 . In situ spectroscopy and ab initio molecular dynamics (AIMD) reveal that surface F species serve as hydrogen‐bond acceptors that reconfigure the interfacial water network, enhancing K + enrichment, local alkalinity, CO 2 accumulation, and rapid proton transfer. Density functional theory (DFT) further indicates that F‐Bi surface, combined with the K + /H 2 O microenvironment, facilitates charge redistribution, enhances *CO 2 and *OCHO adsorption, and then lowers the reaction energy barrier. This work overcomes the intrinsic activity–selectivity trade‐off in CO 2 electrolysis, offering a promising strategy for designing high‐performance pH‐universal electrocatalysts.