Electrodeposition of cobalt nanoparticles: An analysis of the mechanisms behind the deviation from three-dimensional diffusion-control

Electrochemical nucleation and growth of cobalt nanoparticles on aluminium was investigated by potentiostatic electrodeposition from cobalt sulphate solutions buffered with boric acid. At sufficiently low overpotential, the experimental current transients could be fairly reproduced by a mathematical...

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Bibliographic Details
Published in:Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2019-10, Vol.851, p.113413, Article 113413
Main Authors: Altimari, Pietro, Schiavi, Pier Giorgio, Rubino, Antonio, Pagnanelli, Francesca
Format: Article
Language:English
Subjects:
Aluminum
Charge transfer
Cobalt nanoparticles
Cobalt sulfate
Deviation
Diffusion control
Diffusion rate
Electrodeposition
Mathematical models
Mixed kinetic-diffusion control
Nanoparticles
Nucleation
Three-dimensional growth
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Summary:Electrochemical nucleation and growth of cobalt nanoparticles on aluminium was investigated by potentiostatic electrodeposition from cobalt sulphate solutions buffered with boric acid. At sufficiently low overpotential, the experimental current transients could be fairly reproduced by a mathematical model describing nucleation and growth under mixed kinetic-diffusion control, yielding an estimated number of particles per surface area in agreement with the SEM analysis of the deposits. However, the model gave estimates for the charge-transfer kinetic constant several orders of magnitude lower as compared to the Tafel analysis of cobalt electrodeposition on a previously electrodeposited cobalt film. This deviation can be explained by the inhibition of the direct attachment of metal ions, which can be induced by the adsorption of hydrogen onto cobalt particles and/or the formation of stable nanocluster aggregates. The implemented model failed to reproduce the current transients generated at larger overpotential values. A revision of the implemented mathematical model overcoming this limitation is proposed. •Cobalt particles are electrodeposited on aluminium from solutions with boric acid.•Diffusion control cannot explain the potentiostatic current transients.•A model-based analysis is presented yielding reliable nucleation kinetic parameters.•Direct attachment is inhibited inducing mixed kinetic-diffusion control.•A model revision is proposed to improve the description of the current transients.
ISSN:1572-6657
1873-2569
DOI:10.1016/j.jelechem.2019.113413