A Kinetic and AFM Study of the Electrodeposition of Palladium Nanoclusters onto Highly Oriented Pyrolytic Graphite (HOPG)

In the present work we have carried out a kinetic and morphological study of the palladium electrodeposition onto highly oriented pyrolitic graphite electrode from an aqueous solution [0.001 M PdCl 2 + 1 M NH 4 Cl (pH 7)]. From the potentiostatic study were calculated the diffusion coefficient (3.2 × 10 −6 cm 2 s −1 ), the number of active nucleation sites ( N 0 ), the nucleation rate ( A ) and the rate constant of the proton reduction process ( k PR ). A , N 0 and k PR values were potential dependent and they increased with an augment in the applied overpotential. At higher overpotential, it is possible to induce the formation of small Pd clusters with 5 nm in height and an average size of 20–30 nm in diameter.