Kinetics and Thermodynamics of Metal
Cluster Nucleation Over Graphene Oxide
Abhay Gupta and Chandan Srivastava
Abstract An assessment of nucleation and growth mechanism of tin and cobalt
over graphene oxide (GO) substrate is performed using the cyclic voltammetry (CV)
and chronoamperometry (CA) techniques. The CV tests revealed that deposition
of tin and cobalt on GO is an irreversible and diffusion-controlled process. From
the CA tests, it was deduced that the deposition process involved the formation of
adatom layer at the substrate-electrolyte interface prior to nucleation and growth.
Proton reduction reaction over the deposited metal nuclei also took place simultaneously with three-dimensional diffusion-controlled nucleation and growth. While
the deposition mechanism for both metals exhibits similarity, the kinetic parameters
like nucleation rate constant (A) and number density of active nucleation sites (N 0 )
varied tremendously for both metals. Application of classical and atomistic theory
of nucleation revealed that the Gibb’s free energy required for the formation of critical nucleus for Sn and Co deposition was comparable to room temperature thermal
energy and the size of supercritical nucleus is one atom. This meant that under the
experimental conditions of deposition, every Sn and Co atom that deposited over GO
is a supercritical nucleus that can grow irreversibly.
Keywords Nucleation · Tin · Cobalt · Chronoamperometry · Cyclic voltammetry
Introduction
Electrodeposition of metal/alloy coatings is very essential for the corrosion protection of underlying substrates. An important field of study is the addition of secondary
phase in the metal/alloy coating to improve the electrochemical properties [1–4].
Carbonaceous materials like carbon nanotubes (CNTs), graphene, or graphene oxide
(GO) have been extensively used in this regard because of their inherent inert nature
towards the corrosive medium and their ability to influence the crystallographic
A. Gupta · C. Srivastava (B)
Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
e-mail: csrivastava@iisc.ac.in
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_15
229
Cluster Nucleation Over Graphene Oxide
Abhay Gupta and Chandan Srivastava
Abstract An assessment of nucleation and growth mechanism of tin and cobalt
over graphene oxide (GO) substrate is performed using the cyclic voltammetry (CV)
and chronoamperometry (CA) techniques. The CV tests revealed that deposition
of tin and cobalt on GO is an irreversible and diffusion-controlled process. From
the CA tests, it was deduced that the deposition process involved the formation of
adatom layer at the substrate-electrolyte interface prior to nucleation and growth.
Proton reduction reaction over the deposited metal nuclei also took place simultaneously with three-dimensional diffusion-controlled nucleation and growth. While
the deposition mechanism for both metals exhibits similarity, the kinetic parameters
like nucleation rate constant (A) and number density of active nucleation sites (N 0 )
varied tremendously for both metals. Application of classical and atomistic theory
of nucleation revealed that the Gibb’s free energy required for the formation of critical nucleus for Sn and Co deposition was comparable to room temperature thermal
energy and the size of supercritical nucleus is one atom. This meant that under the
experimental conditions of deposition, every Sn and Co atom that deposited over GO
is a supercritical nucleus that can grow irreversibly.
Keywords Nucleation · Tin · Cobalt · Chronoamperometry · Cyclic voltammetry
Introduction
Electrodeposition of metal/alloy coatings is very essential for the corrosion protection of underlying substrates. An important field of study is the addition of secondary
phase in the metal/alloy coating to improve the electrochemical properties [1–4].
Carbonaceous materials like carbon nanotubes (CNTs), graphene, or graphene oxide
(GO) have been extensively used in this regard because of their inherent inert nature
towards the corrosive medium and their ability to influence the crystallographic
A. Gupta · C. Srivastava (B)
Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, India
e-mail: csrivastava@iisc.ac.in
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_15
229