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 PdCl2 + 1 M NH4Cl (pH 7)]. From the potentiostatic study were calculated the diffusion coefficient (3.2 × 10−6 cm2 s−1), the number of active nucleation sites (N0), the nucleation rate (A) and the rate constant of the proton reduction process (kPR). A, N0 and kPR 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.