Rational Design of Pd Anchored Rough Nickel Foam Modulated Through Mofs(Nife) Interlayer for High-Efficiency Electrochemical Dechlorination: The Importance of Ni-O-Fe Bonds

Abstract

A nickel-iron bimetallic organic framework (MOFs(Ni3Fe1)) served as an interlayer to modify Pd@RNF in the synthesis of a Pd@MOFs(Ni3Fe1)/RNF electrode, which was used for ECH of TCAA. Compared to monometallic MOFs(Ni) and MOFs(Fe), the introduction of MOFs(Ni3Fe1) with interfacial Ni-O-Fe bonding markedly enhanced electron transfer capability, consequently boosting the electrode's electrocatalytic activity. Besides, MOFs(Ni3Fe1) also showed optimal surface morphology and the largest specific surface area, which increased the electron density and improved utilisation of Pd. Here the Pd@MOFs(Ni3Fe1)/RNF electrode exhibited superior TCAA dechlorination performance with a removal efficiency of 92.1% in 60 min and positive stability over five consecutive cycles. This enhanced performance is primarily due to the cooperative interaction between Pd and Ni, which was further bolstered by the formation of Ni-O-Fe bonds. Furthermore, the scavenger experiments and ESR analysis revealed that the reduction process involving H*ads was the primary factor responsible for the removal of TCAA. Theoretical calculations were employed to analyze the impact of the adsorption strength of H*ads at various electrode surfaces for the dechlorination of TCAA. This study presents new perspectives on development of electrodes with high levels of electrocatalytic activity and exceptional stability for the dechlorination treatment.

Keywords: Electrocatalytic hydrodechlorination, MOF(NiFe), Ni-O-Fe bonding, TCAA