Solvation-Mediated Ammonia Synthesis in a Nanoheterogeneous Liquid Alloy

Abstract

Liquid catalysts challenge the conventional notion of active site, because reactivity can arise from transient solvation environments formed within dynamically structured liquids. Here, we investigate this effect for ammonia synthesis in a liquid Li–Na alloy using machine learning-accelerated molecular dynamics and enhanced sampling simulations. We show that Li0.64Na0.36, close to its consolute point, forms nanoscale Li-rich and Na-rich domains separated by fluctuating interfaces. These transient environments play distinct and cooperative roles along the reaction pathway. Molecular nitrogen is preferentially activated in Li-rich coordination environments, where strong electron donation weakens the N–N bond and promotes dissociation. In contrast, progressive hydrogenation of nitrogen intermediates is accompanied by increasing stabilization in Na-rich regions. Ammonia formation, therefore, proceeds through a solvation-mediated mechanism in which chemical transformations are coupled to the redistribution of reactive species across dynamically evolving liquid domains. These findings suggest that liquid alloy catalysts can be designed by controlling nanoscale heterogeneity, allowing dynamic solvation environments to orchestrate the sequence of catalytic steps.