Mechanoluminescence-Enhanced Ammonia Synthesis via Mechanochemical Nitrate Reduction

Abstract The Haber–Bosch process remains the dominant method for ammonia (NH3) synthesis, but it is highly energy-intensive and environmentally burdensome. Nitrate reduction to ammonia (NRA) presents a promising dual-function alternative, enabling both sustainable NH3 production and environmental remediation. However, current NRA methods, primarily photocatalytic and electrocatalytic, depend heavily on external energy inputs (light or electricity), limiting their deployment in off-grid or distributed settings. Here, we report a mechanoluminescence (ML)-enhanced mechanocatalysis strategy for mechanically driven NRA using Mn-doped CaZnOS (Mn–CaZnOS) as an efficient mechano-catalyst. Under mechanical stimulation, Mn–CaZnOS generates a synergistic cascade of piezoelectric and photoexcitation effects that facilitate the NRA process. This ML-enhanced system achieves a notable NH3 yield rate of 5.4 μmol g–1 h–1 with exceptional stability over 100 h. Mechanistic investigations, including isotope labeling, kinetic isotope effect, and electron spin resonance, confirm the reaction pathway and identify hydrogenation as the rate-limiting step. Kelvin probe force microscopy and density functional theory calculations reveal that mechanical stimuli induce piezopotential, enriching local NO3– concentration and enhancing proton-coupled charge transfer. Additionally, the electronic structure of the active sites is modulated to enhance intermediate adsorption and reduce the energy barrier for NH3 formation. This work establishes ML-assisted mechanocatalysis as a mechanically driven platform for sustainable ammonia synthesis and environmental cleanup.