Monolayer formation by instantaneous two-dimensional nucleation in the case of electrolytic crystal growth

Abstract

The formation kinetics of monoatomic layers on a (100) screw-dislocation free face of a silver single crystal is investigated experimentally by means of the double-pulse potentiostatic method. Two-dimensional nuclei are formed with an initial pulse at a higher overpotential and are grown at a lower overpotential to complete a monolayer. The current transients recorded are in good agreement with the theoretical model of monolayer deposition by instantaneous two-dimensional nucleation and growth. From each transient the number of nuclei participating in the monolayer formation and the nucleation rate are determined. From sets of transients with different nucleation pulses the time dependence of the number of nuclei and the overpotential dependence of the nucleation rate are obtained. The kinetics of two-dimensional nucleation is found to be stationary. The overpotential dependence of the nucleation rate is in good agreement with the theory, giving the possibility of evaluation of kinetic parameters.