Electrodeposition of particles electrokinetic vs. diffusion control

Early work on single particle nucleation and growth involved the use of either Pt or carbon microelectrodes on which was deposited a material which had a suitably low nucleation density, for instance, Ag, Hg, or Cu (11-13). Later work expanded this to look at other systems such as Pb02 on carbon (37), or PbS04 on Pb (34). Working with single particles allows analysis of the electrokinetics of deposition without the complication due to overlap of growing particles or their diffusion spheres. 

After the induction period, growth of the particle may be measured by following the current transient. Typically, analyses of current transients during the single nucleation and growth of a particle have been performed either at low overpotentials so that growth is assumed under electrokinetic control (34) 

Comparison of mass transport coefficient for particles of different sizes 

Note Also shown are the disk rotation rates required to produce the same mass transport coefficient in a rotating disk experiment. Calculations assume D = 1.00 X 10 cm s and v = 0.01 cm s .  

A more complete analysis of single particle and growth suggests that under combined electrokinetic and diffusion control, and taking into account the concentration overpotential due to depletion of reactant at the surface, the radius and current associated with the growth of a particle as a function of time should foUow (40) 

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