Insights into the enhanced performance of NiCo-LDH modified Pd/NF cathode for electrocatalytic hydrodechlorination

To obtain an electrocatalytic hydrodechlorination (ECH) cathode with low noble metal content, low energy consumption and high catalytic activity, a novel electrode that arming Pd with NiCo-layered double hydroxide (Pd/NiCo-LDH/NF) was prepared. The Pd/NiCo-LDH/NF electrode shows excellent ECH activity, having a mass activity of 32.80 min−1 gPd−1 for dechlorination of 2,4-dichlorophenol (2,4-DCP), which is 5 ∼ 10 times higher than other reports on ECH cathodes. The higher ECH activity is due to the synergistic effect between NiCo-LDH interlayer and Pd2+. The influence of preparation parameters on morphology, composition, conductivity and hydrogen evolution performance of the NiCo-LDH was investigated by means of scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma emission spectrometer, cyclic voltammetry, electrochemical impedance spectroscopy, and linear scanning voltammetry. Density functional theory (DFT) analysis results showed that the NiCo-LDH containing OH− vacancies enhanced the generation of Hads*, weakened the toxicity of phenol to the electrode, and improved the ECH activity of the electrode. This work designed a robust electrocatalytic cathode with low energy consumption, low cost and high efficiency for the ECH of chlorinated phenols.