Performance and mechanism of palladium-based binary nanowires for electrocatalytic removal of halogenated PPCPs

In order to enhance the catalytic activity of Pd nanoparticles and reduce the amount of Pd, the present study was carried out to construct nanowire structures by surfactant-directed hydration method to further increase the active sites on the surface of Pd and improve the yield of atomic hydrogen (H^⁎). The introduction of cheap metal Ni effectively reduced the Pd dosage and increased the utilization of Pd. Nitrogen-doped ordered mesoporous carbon (NOMC) was incorporated to facilitate the dispersion of Pd particles and improve the stability of the catalyst while ensuring the catalytic activity. The prepared palladium-nickel nanowires/nitrogen-doped ordered mesoporous carbon/carbon (Pd-Ni NWs/NOMC/C) electrodes showed excellent efficiency for the removal of halogenated pharmaceuticals and personal care products (PPCPs). The combination of palladium-nickel nanowires (Pd-Ni NWs) with NOMC enhanced the electron transfer capability at the electrode surface and improved the H^⁎ yield. The results showed that the removal efficiency of this electrode for lornoxicam reached 97.2 % at 270 min. The electrode reduced the amount of Pd while stabilizing the electrocatalytic effect. The dechlorination mechanism of Pd-Ni NWs/NOMC/C electrode for lornoxicam was also proposed, and the reaction products and their toxicity were analyzed. This study provided a new idea for designing and synthesizing metal composite catalysts, reduced the cost of catalyst preparation, and had a good application prospect in the treatment of wastewater containing halogenated organic compounds.