Heterointerface Engineering of Bismuth Nanosheets/Nitrogen‐Doped Carbon Nanoleaves Enables High‑Performance Electrochemical Dechlorination

ABSTRACT Chloride ion capture from industrial wastewaters presents a persistent challenge, constrained by the corrosive characteristics of accumulated Cl ⁻ and the limitations of conventional dechlorination technologies. Herein, we introduce a MOF‑mediated 2D‑on‑2D heterointerface engineering strategy to fabricate bismuth nanosheets coupled with nitrogen‐doped carbon nanoleaves (BiNS/NCL). As a Faradaic dechlorination anode in capacitive deionization (CDI), the rationally designed BiNS/NCL heterointerface delivers an impressive chloride adsorption capacity of 108.7 mg g ⁻¹ with an adsorption rate of 24.8 mg g ⁻¹ min ⁻¹ , along with remarkable charge efficiency (86.9%) and low energy consumption (0.39 Wh g ⁻¹ ). The BiNS/NCL electrode also demonstrates exceptional chloride selectivity over competing anions and maintains stable performance over extended cycling. Integrated ex situ/in situ characterizations and density functional theory simulations reveal that a built‑in electric field formed at the BiNS/NCL interface thermodynamically favors chloride electrosorption, accelerates ion transport kinetics, and stabilizes the reversible Bi/BiOCl phase transformation. This study elucidates an interface‐mediated dechlorination mechanism and provides a generalizable heterointerface‑engineering strategy for energy‑efficient electrochemical dechlorination systems.