Fe-doped NiO nanoarray interlayer-modified Pd/Ni foam cathode for enhanced electrocatalytic hydrodechlorination

Electrocatalytic hydrodechlorination (ECH) is a promising technology that efficiently removes persistent chlorinated organic contaminants from water. Herein, a Fe-doped NiO nanoarray interlayer-modified Pd/Ni foam (Pd/Fe-NiO/NF) was synthesized as an efficient cathode catalyst for ECH of 2,4-dichlorophenoxyacetic acid (2,4-D). Results revealed that the grown Fe-NiO nanoarray on nickel foam increased the electrochemically active surface area of the electrode and improved the dispersion of catalytically active Pd nanoparticles (Pd NPs). More importantly, introducing the Fe-NiO interlayer facilitated water ionization (Volmer reaction) and atomic H* generation, which afforded the anchored Pd NPs more atomic H* for the ECH process. Compared with the conventional Pd/NF electrode, the 2,4-D dechlorination efficiency of Pd/Fe-NiO/NF was enhanced to 100% within 90 min, and its Pd requirement was reduced by 76.7%. In addition, Pd/Fe-NiO/NF exhibited excellent reusability and stability during six consecutive cycles. This study proposes a feasible strategy for designing effective dechlorination electrocatalysts with less precious metals.