Fractal growth of platinum electrodeposits revealed by in situ electron microscopy

Lifen Wang, Jianguo Wen, Huaping Sheng and Dean J. Miller, 2016

Image courtesy of Nanoscale

Abstract

Fractals are commonly observed in nature and elucidating the mechanisms of fractal-related growth is a compelling issue for both fundamental science and technology. Here we report an in situ electron microscopy study of dynamic fractal growth of platinum during electrodeposition in a miniaturized electrochemical cell at varying growth conditions. Highly dendritic growth – either dense branching or ramified islands – are formed at the solid-electrolyte interface. We show how the diffusion length of ions in the electrolyte influences morphology selection and how instability induced by initial surface roughness, combined with local enhancement of electric field, gives rise to non-uniform branched deposition as a result of nucleation/growth at preferred locations. Comparing the growth behavior under these different conditions provides new insight into the fundamental mechanisms of platinum nucleation.

Impact Statement

Platinum electrodeposition onto the surface of glassy carbon electrodes during cyclic voltammetry experiments was characterized. Fractal growth of platinum occurred during early growth and surface roughnesss of the electrode and ion diffusion were found to be integral to the resulting deposited platinum structures.
Keywords: Electrochemistry; Plating