Engineering Cu-porphyrin interlayer in Pd doped sponge Ni electrode for enhanced electrocatalytic dechlorination of 4-chlorophenol

Tailoring a highly active interlayer in Pd electrodes is critical for determining electrode performance and stability. In this study, an active Cu-porphyrin interlayer is electrodeposited onto the sponge nickel (SN) skeleton. The modified sponge nickel is subsequently used to support Pd particles and fabricate an effective Pd/Cu-P/SN composite electrode. Compared with the initial Pd/SN electrode, the increase in dechlorination efficiency is 3.59 times for the Pd/Cu-P/SN electrode. Furthermore, substantial improvements in both mass activity and current efficiency are achieved, with respective increases of approximately 14.2-fold and 4.2-fold relative to the untreated electrode. These significant enhancements are ascribed to the well-designed active Cu-porphyrin interphase. Specifically, the Cu-porphyrin interlayer on the SN skeleton provides an enlarged specific surface area, thus accommodating a greater dispersion of Pd particles. Additionally, the confinement of Pd particles on Cu-porphyrin regions leads to the establishment of Pd Cu interfaces, and this interfacial intimacy expedites the evolution of active hydrogen, leading to a high electrocatalytic removal rate even at an elevated 4-chlorophenol concentration. The Pd/Cu-P/SN composite electrode presented here shows a great application potential for the electrocatalytic treatment of organic chlorophenol wastewater, which also paves a new avenue for enhancing electrode properties through rational introducing of metal-porphyrin interphase.