Nucleation mechanism of silver during electrodeposition on a glassy carbon electrode from a cyanide-free bath with 2-hydroxypyridine as a complexing agent

The initial stage of silver electrodeposition on a glassy carbon electrode from a cyanide-free bath with 2-hydroxypyridine (2-HP) as the complexing agent is studied. The influence of polyethyleneimine (PEI) as an additive on the nucleation and growth of silver are also examined. Progressive nucleation mechanism is found for silver deposition according to Scharifker-Hills' model with three-dimensional diffusion-controlled growth nucleation. This mechanism cannot be influenced by adding PEI. However. the diffusion coefficient of the silver-2-HP complexes and the density of nuclei exhibit a remarkable decrease with the addition of PEI. Smoother and brighter silver deposits with progressive nucleation features were obtained in the presence of PEI from the images of scanning electron microscopy. (C) 2009 Elsevier B.V. All rights reserved.