Chapter 9
Electrosynthesis of Nanostructures
Without a Coating Formation
on Electrodes
9.1 Synthesis of Nanoparticles on Electrodes
9.1.1 Metal Nanoparticle Formation by Direct
Electrochemical Reduction of Metal Ions
The common goal of electroplating is the production of a compact, well-adherent
layer on the substrate material. Although various additives are used in conventional
industrial plating processes to tune the properties of the deposits, these additives
should never make a film that prevents the deposition of the metal atoms on the
substrate surface. In contrast to the metal film formation, the cathodic nanoparticle
production is based on the application of stabilizers that, on the one hand, prevent
the formation of a compact deposit film on the cathode; and, on the other hand, act
as stabilizer of the metal particles formed.
Here we have to recall Fig. 2.2 where the electrical double layer structure is
depicted with strongly adsorbing ions that are comparable in size with both the
solvent molecules and the cations that can be reduced on the electrode. The difference
between this classical case and the studies discussed in this chapter is as follows:
For metal particle production, the charge on the metal is negative, and the ions
electrostatically attached to the electrode are bulky cations that prevent the metal
cations to approach the metal surface itself, and the charge transfer is likely to take
place through the fairly thick cationic film on the negatively charged metal.
In all studies published so far, tetraalkylammonium salts with different alkyl chain
lengths were applied as adsorbent layer. If the alkyl groups are identical, tetrabutylammonium is the smallest cation applied [1–3], but the alkyl chain may be significantly
larger, too (like the octyl group [4]). If an asymmetrical cation is used, the common
solution is the application of alkyltrimethylammonium cations, most frequently with
a cetyl group as the long-chained part of the cation [5–9]. Salts with hydrophobic
cations having unusually large alkyl chains are applied as growth modifiers [10, 11]
that result in the growth of elongated nanoparticles. Unfortunately, in the majority of
© Springer Nature Switzerland AG 2021
L. Péter, Electrochemical Methods of Nanostructure Preparation,
Monographs in Electrochemistry, https://doi.org/10.1007/978-3-030-69117-2_9
303
Electrosynthesis of Nanostructures
Without a Coating Formation
on Electrodes
9.1 Synthesis of Nanoparticles on Electrodes
9.1.1 Metal Nanoparticle Formation by Direct
Electrochemical Reduction of Metal Ions
The common goal of electroplating is the production of a compact, well-adherent
layer on the substrate material. Although various additives are used in conventional
industrial plating processes to tune the properties of the deposits, these additives
should never make a film that prevents the deposition of the metal atoms on the
substrate surface. In contrast to the metal film formation, the cathodic nanoparticle
production is based on the application of stabilizers that, on the one hand, prevent
the formation of a compact deposit film on the cathode; and, on the other hand, act
as stabilizer of the metal particles formed.
Here we have to recall Fig. 2.2 where the electrical double layer structure is
depicted with strongly adsorbing ions that are comparable in size with both the
solvent molecules and the cations that can be reduced on the electrode. The difference
between this classical case and the studies discussed in this chapter is as follows:
For metal particle production, the charge on the metal is negative, and the ions
electrostatically attached to the electrode are bulky cations that prevent the metal
cations to approach the metal surface itself, and the charge transfer is likely to take
place through the fairly thick cationic film on the negatively charged metal.
In all studies published so far, tetraalkylammonium salts with different alkyl chain
lengths were applied as adsorbent layer. If the alkyl groups are identical, tetrabutylammonium is the smallest cation applied [1–3], but the alkyl chain may be significantly
larger, too (like the octyl group [4]). If an asymmetrical cation is used, the common
solution is the application of alkyltrimethylammonium cations, most frequently with
a cetyl group as the long-chained part of the cation [5–9]. Salts with hydrophobic
cations having unusually large alkyl chains are applied as growth modifiers [10, 11]
that result in the growth of elongated nanoparticles. Unfortunately, in the majority of
© Springer Nature Switzerland AG 2021
L. Péter, Electrochemical Methods of Nanostructure Preparation,
Monographs in Electrochemistry, https://doi.org/10.1007/978-3-030-69117-2_9
303