1.1 The “Nano” Era
5
Although the vision of the atomic-scale manipulation of materials, including the
molecular-level drive of the chemical reactions [1] is very appealing, the big majority
of the electrochemical processes involving nanomaterials is based on classical electrochemical techniques and do not require nanoscale tools at all. This is why the
understanding of both the formation of nanostructures and their electrochemical
background should go along with each other.
As it was emphasized also by Feynman [1], nanostructuring is by far not only
about miniaturization. Manufacturing a device in a miniature form can save material
and energy, but nanostructuring often leads us to a field where the counterparts of
the effects occurring cannot be found in the conventional macroscopic world. The
increase of the efficiency of a nanostructured catalyst can be explained simply by the
reduced transfer time of the intermediate from one active center to another, and the
process is easily elucidated by a downscaling. However, it is rather unusual that the
charging of a metal nanoparticle is accompanied by a step in the electrical potential,
although this behavior is a direct consequence of the change of the density of the
surface charge. Here, the quantized nature of the charge is of importance, while the
description of the potential—charge density relationship can be fully classical. The
mechanical behavior of a defect-free single crystal cannot be described by the same
manner as the dislocation slipping and elongation is treated in the mechanics of
macroscopic objects. Similarly, the magnetic behavior of a single-domain particle
is different from a macroscopic multidomain magnet. The electrical resistivity of
a metallic structure also changes as the characteristic length in the nanostructure
becomes comparable to the mean free path of the electrons (quantum confinement).
Magnetic objects in the close vicinity of each other may also exhibit a magnetic
coupling interaction that is not known in any sense in the macroscopic world—this
gives rise to the special magnetoresistance behavior of nanometric magnetic/nonmagnetic multilayers. A nanostructured metal surface may interact with the light in
a manner that has no parallel phenomenon on a plain metal surface and what can be
explained by the relevant surface plasmon effects.
The above examples clearly show that “nanostructuring”, if treated in the right
way, always must have the thoughtful background. It is not enough to see that in
the field of electrochemical publications the ratio of nanostructure-related papers
grew from 20 to 50% in the decade between 2005 and 2015. Should this make
nanostructuring a fashionable field, the works with high-quality and long-lasting
impact will be those which can validate the necessity of nanostructuring without any
autotelism.
1.2 The Concept of This Book
The family of nanostructures prepared by means of either a method fully relying on
electrochemistry or an electrochemistry-assisted preparation procedure is very wide.
Not only do these nanomaterials differ a lot in the fine details of the preparation
methods and basic class of materials (like metal or ceramics), but the composition,
5
Although the vision of the atomic-scale manipulation of materials, including the
molecular-level drive of the chemical reactions [1] is very appealing, the big majority
of the electrochemical processes involving nanomaterials is based on classical electrochemical techniques and do not require nanoscale tools at all. This is why the
understanding of both the formation of nanostructures and their electrochemical
background should go along with each other.
As it was emphasized also by Feynman [1], nanostructuring is by far not only
about miniaturization. Manufacturing a device in a miniature form can save material
and energy, but nanostructuring often leads us to a field where the counterparts of
the effects occurring cannot be found in the conventional macroscopic world. The
increase of the efficiency of a nanostructured catalyst can be explained simply by the
reduced transfer time of the intermediate from one active center to another, and the
process is easily elucidated by a downscaling. However, it is rather unusual that the
charging of a metal nanoparticle is accompanied by a step in the electrical potential,
although this behavior is a direct consequence of the change of the density of the
surface charge. Here, the quantized nature of the charge is of importance, while the
description of the potential—charge density relationship can be fully classical. The
mechanical behavior of a defect-free single crystal cannot be described by the same
manner as the dislocation slipping and elongation is treated in the mechanics of
macroscopic objects. Similarly, the magnetic behavior of a single-domain particle
is different from a macroscopic multidomain magnet. The electrical resistivity of
a metallic structure also changes as the characteristic length in the nanostructure
becomes comparable to the mean free path of the electrons (quantum confinement).
Magnetic objects in the close vicinity of each other may also exhibit a magnetic
coupling interaction that is not known in any sense in the macroscopic world—this
gives rise to the special magnetoresistance behavior of nanometric magnetic/nonmagnetic multilayers. A nanostructured metal surface may interact with the light in
a manner that has no parallel phenomenon on a plain metal surface and what can be
explained by the relevant surface plasmon effects.
The above examples clearly show that “nanostructuring”, if treated in the right
way, always must have the thoughtful background. It is not enough to see that in
the field of electrochemical publications the ratio of nanostructure-related papers
grew from 20 to 50% in the decade between 2005 and 2015. Should this make
nanostructuring a fashionable field, the works with high-quality and long-lasting
impact will be those which can validate the necessity of nanostructuring without any
autotelism.
1.2 The Concept of This Book
The family of nanostructures prepared by means of either a method fully relying on
electrochemistry or an electrochemistry-assisted preparation procedure is very wide.
Not only do these nanomaterials differ a lot in the fine details of the preparation
methods and basic class of materials (like metal or ceramics), but the composition,