Ostwald Ripening in Metallic Nanoparticles: Stochastic Kinetics

This paper looks at the factors that control Ostwald ripening in a bimodal silver nanocolloid system containing tabular particles having one dimension equal to or less than 5 nm. The test system was based on a seeded process using the staged addition of sodium borohydride and hydroquinone (HQ) to silver nitrate. The result was a blend of 20 nm spheres and 30 nm/4–5 nm nanodiscs. The mixture of morphologies allows for a greater differentiation in free energy stability between particles and consequently an accelerated rate of ripening. The rate of the ripening process is shown to be heavily dependent on the relative amount of spherical receptor particles as well as on the presence of hydroquinone as a redox catalyst. A stochastic model is proposed for stepwise adatom kinetics.