Test of Nucleation Models from Compiled Data

Abstract

Nucleation models have been tested using reported experimental nucleation data in several systems dealing with electrocrystallization from aqueous solutions, and with a wide range of supersaturations or overpotentials. The critical nucleus size has been calculated and the results obtained with the classical and atomistic models have been compared and discussed. In order to compare these values with those occurring in crystallization, the values of the critical nucleus size for several crystallization systems have also been calculated, and then compared and commented.Keywords: nucleation, electrocrystallization, atomistic model, classical models, critical nucleus size. IntroductionNucleation is an important phenomenon which plays a fundamental role in crystal growth and, especially, in precipitation and electrocrystallization, but also in other fields [1]. Nucleation and its control are going to be very important in the synthesis of nanoparticles and nanostructured materials [2][3][4][5][6][7][8]. Theories of nucleation have been developed along the last century, from both thermodynamic and kinetic points of view [1,[9][10][11][12][13][14]. The phenomenon of electrocrystallization has been treated by several authors [15][16][17][18][19][20][21] and reviewed recently [22][23]. Experimental analysis of nucleation models presents several problems, joined to the control of the system where nucleation occurs or to the nucleation detection technique. As a consequence, notable dispersion is observed in the reported data. Nucleation models predict certain dependence between the nucleation rate and the supersaturation or overpotential acting in the system. To test the classical models as well the atomistic model of nucleation, several systems have been selected dealing with electrochemical nucleation. Not enough systems have been tested in the literature with the atomistic model. One of the points that has deserved less attention in the discussions of the different nucleation