Numerical Simulations of the Kinetics of Metal Nanoparticles Formation

The mechanism of the formation of metal nanoparticles in the solutions under the conditions of their homogeneous nucleation is still the subject for the discussion. The classical LaMer's scheme requires the careful supplementation as well as the 2‐step Finke–Watzky mechanism is quite minimalistic. Based on the principles of the “lump” approximation the kinetic schemes for the different variants of LaMer's mechanism were proposed. It was found that the classical LaMer's approach may be used only for the fitting of the kinetic curves of nanoparticles formation under the conditions of the extremely fast reduction of the metal ions to the corresponding atoms. And vice versa, in the case of slow reduction of metal ions the formation of nucleus occurs in quasi‐stationary regime during the whole process of synthesis of nanoparticles and for the fitting of the kinetic curves the use of the Finke–Watzky scheme is preferable. The physical sense of the reaction rate constants of the Finke–Watzky scheme is partially revealed and the boundary conditions of its application are shown. Additionally, the thermodynamics of a new phase formation is discussed and the approach for the calculation of the critical radius is proposed.