Highly efficient electrocatalytic treatment of high-concentration 4-chlorophenol wastewater on Pd-Cu/PPy/NF composite cathode

Exploring highly active cathode materials for electrocatalytic hydrodechlorination (ECH) of chlorinated organic pollutants is of significant significance in terms of remediating environmental pollution and keeping ecological balance. In this work, polypyrrole (PPy) modified Ni foam (NF) was utilized as an efficient porous skeleton to fabricate Pd-Cu/PPy/NF composite cathode through electro-polymerization and subsequent chemical replacement method. The introduction of PPy interlayer on NF greatly improved the interfacial affinity of the substrate, facilitating to the uniform deposition of Pd-Cu particles. This enabled the formation of a compact and uniform microstructure with intimate contact Pd-Cu interface in the target Pd-Cu/PPy/NF composite electrode. Such structure feature vastly decreased charge transfer resistance and provided an abundance of close-contact Pd-Cu entities for yielding of activated hydrogen, thereby effectively enhancing the electrocatalytic performance of Pd-Cu/PPy/NF electrode for ECH of 4-chlorophenol with a high-concentration (>200 mg·L−1). Noticeably, a high ECH efficiency of approximately 96.9 % was obtained over Pd-Cu/PPy/NF cathode within 60 min. This study provides a simple, facile, and effective pathway to prepare high-performance composite cathode for electroreductive remediation of chlorophenol pollutants with high concentration.