Ni-based layered metal-organic frameworks with palladium for electrochemical dechlorination

Electrocatalytic hydrogenolysis (ECH) appears to be an effective method for remediation of toxic contaminants in natural water. In this work, metallic palladium was loaded on Ni-based layered metal-organic frameworks (NiMOF) using adsorption followed by an electroreduction method. Benefiting from high dispersion of palladium and enhanced adsorption of NiMOF towards 2,4-dichlorophenoxyacetic acid (2,4-D), the as-obtained electrode (Pd-NiMOF/Ni) offers large amounts of active hydrogen and high surface concentration of 2,4-D in the ECH process. Consequently, Pd-NiMOF/Ni displays enhanced activity and selectivity compared to traditional electrodes. In addition, the Pd-NiMOF/Ni cathode was extremely stable, as verified by six successive cycling tests. Co-existing ions, including NO3-, HCO3-, CO32- and Ca2+ exert a negative impact on the electrocatalytic dechlorination, whereas no effect of Cl- on the process. Nonetheless, the electrochemical dechlorination of 2,4-D in Evian water remained effective, demonstrating the potential application of this electrode in efficient dechlorination of chlorinated aromatic compounds.