Controllable Synthesis of Metal Nanoparticles Under Non‐Equilibrium Conditions via an Extended LaMer Mechanism

Synthesis of nanomaterials via plasma plume ablation offers a rapid and surfactant-free route for nanoparticles production. However, controlling nucleation under highly non-equilibrium conditions remains a major challenge, often leading to low yield and poor size uniformity. Here we demonstrate that introducing heterogeneous metal ions into the ablation medium provides an effective strategy to regulate plasma plume. Using pulsed laser ablation in liquids as a model system, we show that dissolved metal ions undergo heterogeneous nucleation, thereby simultaneously suppressing plume redeposition. Using silver ions （Ag⁺） as a representative ion, we identify an optimal concentration window (∼1 mm) that maximized nanoparticle yield while producing uniformly small IrAg nanoparticles. A systematic ion library further reveals that the promotion efficiency across different ions correlates strongly with the standard reduction potential (E°), establishing a quantitative link between ion reducibility and plume behavior. These results demonstrate that thermodynamic driving forces bias the relative rates of reduction and nucleation, thereby selecting the dominant condensation pathway under non-equilibrium conditions. This ion-regulated strategy extends the classical LaMer framework into plasma plume synthesis and provides predictive guidelines for scalable, size-controlled nanomaterial production.