Unveiling the mechanism and performance of electrocatalytic hydrodechlorination of chlorinated PPCPs by electron-rich palladium electrode modulated through PANI-rGO interlayer

Abstract

In order to simultaneously achieve higher dispersion, smaller particle size, and better catalytic performance of Pd, a Pd/Polyaniline-reduced graphene oxide/Nickel foam (Pd/PANI-rGO/NF) electrode is synthesized by introducing conductive PANI-rGO interlayer for electrocatalytic hydrodechlorination (ECH) of typical chlorinated pharmaceuticals and personal care products (PPCPs). 99.3% diclofenac (DCF) and 94.6% clofibric acid (CA) are removed by this electrode within 180 min and the results of risk assessment show that the toxicities of the two typical chlorinated PPCPs are significantly reduced in the aqueous environment. The electrode is characterized and analyzed. The scanning electron microscopy (SEM) and transmission electron microscope (TEM) results indicate that the introduction of PANI-rGO effectively enhances the dispersion of Pd and reduces the size of Pd particle. Meanwhile, the combined analyses of X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and density functional theory (DFT) calculation suggest that electron transfer occurs between the PANI-rGO interlayer and Pd, leading to the formation of electron-rich Pd. Cyclic voltammetry (CV) curve indicates that the PANI-rGO interlayer improves the yield of active adsorbed hydrogen (H*ads). Therefore, the catalytic activities of Pd particles are synergistically improved. This work can provide a beneficial choice for the effective treatment of typical chlorinated PPCPs in the water environment.