Fluorine-Driven Interfacial Reconfiguration for pH-Universal CO₂ Electrolysis at High Current Densities via Enhanced...

High-rate CO₂ electroreduction is challenged by the conflict between sluggish CO₂ activation and hydrogen evolution at high currents, particularly under pH-universal and dilute CO₂ 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-Bi₂O₃), 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 CO₂ feed of 15 vol% CO₂/N₂. 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, CO₂ accumulation, and rapid proton transfer. Density functional theory (DFT) further indicates that F-Bi surface, combined with the K⁺/H₂O microenvironment, facilitates charge redistribution, enhances *CO₂ and *OCHO adsorption, and then lowers the reaction energy barrier. This work overcomes the intrinsic activity-selectivity trade-off in CO₂ electrolysis, offering a promising strategy for designing high-performance pH-universal electrocatalysts.