Electrochemical Nucleation and Growth of Rhenium on Glassy Carbon in the KF-KBF4-B2O3-KReO4 Melt

The initial stages of rhenium electrocrystallization on the glassy carbon electrode from the KF-KBF 4 -B 2 O 3 -KReO 4 (0.88 wt% Re) melt at 773 K were studied using cyclic voltammetry, chronoamperometry, and scanning electron microscopy (SEM). Cyclic voltammetry data indicated the presence of a nucleation process. Analysis of potentiostatic current transients and SEM images demonstrated that the electrocrystallization process occurs by the three-dimensional instantaneous nucleation with diffusion-controlled growth under the studied conditions. The Scharifker–Hills and Scharifker–Mostany theoretical models were used to calculate the nucleation parameters and the diffusion coefficient of rhenium ions.