Palladium Electrodeposition Onto a Carbon Fiber Ultramicroelectrode

In the present work, it was conducted an electrochemical and kinetic study of Pd electrodeposition onto a 7 [micro]m diameter CF (carbon fiber) ultramicroelectrode from an aqueous solution containing 1 mM of Pd[Cl.sub.2] and 1 M N[H.sub.4]Cl as supporting electrolyte, at 25 [degrees]C and pH = 4.5. The voltammetric study suggests that at slow scan rates, radial diffusion is favored. The experimental current density transients obtained from the potentiostatic study were well predicted by an instantaneous nucleation and growth mathematical model, that considers the formation of separated hemispherical nuclei. The number of nuclei formed on the electrode surface is potential dependent, and increases as the applied potential diminishes. Keywords: palladium, kinetics, electrodeposition, carbon fiber.