In-situ chlorine radical generation from captured Cl- for redox synergy in electrocatalytic hydrodehalogenation.

Electrocatalytic dehalogenation can effectively detoxify chlorinated organic pollutants (COPs) by cleaving C-Cl bonds in wastewater treatment, however, it often fails to achieve complete mineralization. In particular, the fate of the released Cl- has often been overlooked and whether they can be recycled and reutilized to facilitate pollutant degradation has remained unclear. Herein, a reduction-oxidation cascade system is constructed, in which Cl- liberated during electrocatalytic reduction is directly converted into reactive chlorine species (RCS) during the subsequent oxidation step, enabling complete mineralization of organic pollutants. Quenching experiments and electron paramagnetic resonance spectroscopy (EPR) confirm the in situ reutilization of detached Cl-. Laser scanning confocal microscopy (LSCM) visualizes the adsorption and transformation of Cl- on the electrode surface, while ab initio molecular dynamics (AIMD) calculations reveal the interfacial concentration distribution of Cl- and the energy profiles of its migration. This work establishes a cascade electrocatalytic strategy that couples reduction and oxidation, enabling chlorine reutilization and providing a sustainable pathway for the removal and resource recovery of COPs.