Construction of Pd/Ni2P-Ni foam nanosheet array electrode by in-situ phosphatization-electrodeposition strategy for synergistic electrocatalytic hydrodechlorination

[Display omitted] •Pd/Ni2P-Ni foam electrode was prepared by in-situ phosphating-electrodeposition and applied to EHDC.•The electrode has 3D foam structure, porous skeleton surface and high Pd dispersion.•The Pd/Ni2P-Ni foam electrode delivered an unprecedented high mass activity.•Substitution of Ni2P for majority Pd0 provides Habs for EHDC reaction and improves the utilization of Pd. Designing a high-efficiency electrocatalyst with low Pd loading on the electrodes is the key to the electrocatalytic hydrodechlorination (EHDC) of chlorophenols (CPs) but still challenging. Herein, a novel three-dimensional network structure Pd/Ni2P-Ni foam nanosheet array electrode with Pd loading content only 1 wt% was prepared by an in-situ phosphatization-electrodeposition strategy for robust EHDC. The EHDC performance of the constructed Pd/Ni2P-Ni foam electrode was tested with 4-CP as the model pollutant. Complete dechlorination is achieved within 90 min, and the consumption of Pd is reduced by 50 %. The mechanism study shows that the improvement of EHDC performance can be attributed to the synergistic effect of Ni2P nanosheets and Pd NPs, in which Ni2P replaces Pd0 to produce atomic hydrogen (Hads), and promotes more Pd2+ generation, which is beneficial to the fracture of the C-Cl bond, thus improving the mass activity of Pd and the EHDC performance simultaneously. This work provides a simple and practical strategy for designing low noble metal supported catalysts with high EHDC performance.