Semi‐Ionic C‐F Bonds Modulate Hydrogen Dynamics for Selective CO ₂ ‐to‐CH ₄ Electroreduction on Carbon Quantum Dots

Abstract

ABSTRACT Electrochemical CO 2 reduction to CH 4 represents an attractive route for carbon recycling and energy storage, but remains limited by sluggish hydrogenation kinetics and ineffective management of reactive hydrogen species. Herein, we develop a molecular fusion strategy to synthesize fluorine‐rich carbon quantum dots (F1‐CQDs) featuring an unprecedented F content of up to 28.8 at. % in optimized F1‐CQDs. The catalyst delivers a CH 4 Faraday efficiency of 63.2% together with a CH 4 partial current density of 210.8 mA cm −2 in a flow cell. Combined in situ spectroscopy and theoretical calculations reveal that semi‐ionic C‐F bonds create abundant Lewis basic sites that selectively stabilize key CO 2 ‐reduction intermediates, while also regulating hydrogen dynamics by facilitating water activation and transient active hydrogen (*H) formation on neighboring carbon sites. This synergistic dual‐site functionality enhances the effective *H availability for stepwise hydrogenation without excessively favoring the competing hydrogen evolution reaction, as clarified by isotope labeling and *H‐scavenging experiments. This work establishes a clear structure‐activity relationship between C‐F bonding and catalytic performance, and provides a general design principle for metal‐free electrocatalysts through the coupled engineering of intermediate stabilization and hydrogen kinetics.