Enhanced electrochemical dechlorination of 4-chlorophenol on a nickel foam electrode modified with palladium, polypyrrole and graphene

摘要

A composite electrode of Pd/polypyrrole-reduced graphene oxide/foam nickel (Pd/PPy-rGO/NF) with excellent dechlorination performance was prepared by pulse electrodeposition of Pd nanoparticles on the interlayer of PPy-rGO. The physicochemical properties of the electrode were systematically characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and cyclic voltammetry. 4-chlorophenol (4-CP) was selected as a model chlorinated organic pollutant to investigate the dechlorination property of electrodes and optimize the dechlorination conditions and electrode preparation conditions. The results indicated that the morphology of the Pd/PPy-rCO/NF electrode exhibited porous nano-grids, and the Pd content as low as 0.430 mg/cm(2). By using this electrode, 95.8% of 4-CP could be dechlorinated in 120 min with a relatively high current efficiency of 39.9%. A new parameter named as specific current efficiency (SPCE), which can be calculated through dividing the current efficiency by the Pd content on unit electrode surface, was proposed to estimate the role of Pd in dechlorination. The SPCE obtained in this work was as high as 92.9%/(mg/cm(2)). Compared with the electrode without the interlayer of PPy-rGO, the Pd/PPy-rGO/NF electrode presented higher dechlorination activity and better stability. The studies here may contribute to the development of the electrocatalytic electrode that can be used as a potential candidate for eliminating chlorinated pollutants. (C) 2020 Elsevier B.V. All rights reserved.