The development of electrode materials that combine high capacity with high anion selectivity is critical for chloride separation from complex aqueous matrices. Here, a NiFe LDH/BiOCl composite film electrode was fabricated on carbon paper via sequential electrodeposition and employed for electrically switched ion exchange (ESIX) of chloride. The composite delivers higher reversible chloride uptake than either NiFe LDH or BiOCl alone under identical electrochemical conditions, together with enhanced selectivity in mixed−anion solutions. Mechanistically, the synergy originates from the combination of (i) the high anion−exchange capacity and redox−tunable layer charge of NiFe LDH and (ii) halide−affinitive BiOCl domains that facilitate voltage−gated uptake/release; the heterointerface further improves charge/ion transport, enabling more effective electrochemical utilization. The electrode maintains stable cycling performance with high regeneration efficiency over repeated ESIX operation. Compared with representative LDH− or BiOX−based ESIX electrodes reported for halide capture, the proposed composite shows competitive chloride selectivity and reversible cycling, supporting its potential for electrochemical separations and water treatment.
Li et al. (Tue,) studied this question.