Three-Dimensional Pine-Needle-like Ni-MoC Heterostructure Enable Efficient C-Cl Bond Activation for Electrocatalytic Hydrodechlorination

Abstract

Electrocatalytic hydrodechlorination (EHDC) has emerged as a promising technology for simultaneous pollutant remediation and valorization. However, the scarcity of electrocatalysts exhibiting high activity and selectivity has hindered its practical application. Herein, a three-dimensional (3D) pine-needle-like nickel-molybdenum carbide heterostructure supported on nickel foam (Ni-MoC/NF) was constructed for EHDC, which features a large specific surface area and abundant Ni-MoC heterointerfaces. Benefiting from these structural merits, Ni-MoC/NF efficiently catalyzes the EHDC of 4-chlorophenol (4-CP) to phenol with high conversion efficiency (96% in 120 min), a superior current efficiency of 29.9%, and a large reaction rate constant of 2.5×10-2 min-1, rivaling those of advanced Pd-based materials. Mechanistic investigations and DFT calculation reveal that the synergistic effect between Ni and MoC induces electron-deficient Ni active sites, which facilitate the nucleophilic attack of active atomic hydrogen (H*) on the C-Cl bond by reducing the energy barrier. The electron-deficient Ni sites interact with the 4-CP, disrupting its p-π conjugation and thereby activating the C-Cl bond. This work demonstrates that engineering the electronic states of catalytic active sites can effectively activate C-Cl bonds, thereby enhancing EHDC performance and providing a promising strategy for developing non-palladium catalysts.