Atomic-Scale Synergy of Dynamic Electric Fields and Ru Catalyst Architectures in Plasma-Catalyst NH3 Synthesis: A ReaxFF MD/DFT Mechanistic Study and Experiment

XY Lu and Q Chen and J Chen and MH Liang and SY Zhou, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, 13, 15016-15026 (2025).

DOI: 10.1021/acssuschemeng.5c05345

Plasma-catalytic ammonia synthesis offers a sustainable pathway for NH3 production under mild conditions. However, interfacial kinetic bottlenecks persist due to competing charge and mass transport limitations. This work elucidates the dynamic interplay between electric field waveforms (direct current/alternating current (AC)/ns-pulsed) and atomic-scale Ru catalyst architectures in governing nitrogen activation and NH3 synthesis through molecular dynamics simulations, further supported by density functional theory calculations and steady-state experimental validation. AC fields synergize with Ru clusters to amplify molecular transport by 1-2 times, while quantum-confined charge transfer at Ru sites reduces H adsorption barriers from 4.016 to 2.855 eV, mitigating hydrogen passivation. Structural optimization reveals Ru clusters achieve a peak NH3 yield via coordinated active-site ensembles, whereas the single-atom configuration alleviates steric hindrance and, in combination with the electric field effect, can increase the turnover frequency (TOF) from 0.06 ns-1 to 0.32 ns-1. The revealed waveform- structure codependency demonstrates maximal efficiency occurs when the AC field oscillates with the catalyst restructuring kinetics of Ru clusters, enabling simultaneous optimization of N2 adsorption and H desorption through dynamic charge polarization. The study establishes universal design principles: atomic dispersion thresholds (>= 16 & Aring; spacing) prevent selectivity loss caused by quantum confinement, while tailored field waveforms engineer surface charge polarization of the catalyst. Bridging plasma physics with catalytic chemistry, these insights provide a predictive framework for next-generation ammonia systems operating at mild conditions, simultaneously addressing efficiency, stability, and scalability challenges in sustainable nitrogen fixation.

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