Synergistic Surface Engineering of RuPd Nanocatalysts: Orchestrating Reactive Hydrogen Formation, and 2-Chlorophenol Adsorption Dynamics for Enhanced Electrocatalytic Hydrodechlorination

Electrocatalytic hydrodechlorination (EHDC) is a promising strategy for remediating chlorinated organic pollutants by utilizing reactive hydrogen (H*) to cleave C–Cl bonds. Addressing the challenge of simultaneously optimizing H* generation and targeted pollutant adsorption/activation, this work introduces synergistic surface engineering of RuPd alloy nanocatalysts. Compositionally controlled RuPd nanoparticles (RuPd2, Ru2Pd3, and Ru2Pd) were synthesized via seed-mediated growth, yielding uniform sub-3.5 nm nanoparticles with homogeneous elemental distribution. The optimal RuPd2 electrocatalysts achieved 97.1% 2-chlorophenol conversion within 6 h at −0.85 V vs Ag/AgCl, exhibiting a mass activity of 28.3 min–1 g–1Pd, representing a 5.6-fold enhancement over monometallic Pd. Moreover, RuPd2 demonstrated enhanced durability, maintaining performance with less than 5% efficiency loss over 10 cycles. This enhanced EHDC performance originated from dual synergistic effects. Electron transfer from Ru to Pd facilitated H* generation kinetics, evidenced by a near-optimal ΔGH* (−0.25 eV) at Pd–Pd–Pd hollow sites, while Ru-rich surface domains significantly strengthened 2-chlorophenol adsorption and elongated the C–Cl bond to facilitate dechlorination. These spatially separated synergistic sites collectively achieve higher EHDC efficiency, establishing a unified catalyst design strategy that effectively orchestrates coupled surface processes, and provides a significant advance for efficient EHDC technology with broad environmental remediation implications.