Chapter 3
In Situ PM IRRAS Studies
of Redox-Inactive Molecular Films
Adsorbed on Electrodes
Adsorption of ions or neutral molecules on electrode surfaces leads to changes in the
macroscopic properties of surfaces such as the surface energy, contact angle, surface
charge density or surface potential. Potential-dependent adsorption-desorption process of ions or neutral molecules on electrode surfaces belongs to an important
research topic in electrochemistry. Some ions have the ability to adsorb specifically
on electrode surfaces, influencing the surface charge density and surface energy of
the electrode|electrolyte interface [1–3]. The phenomenon of specific adsorption of
ions on metallic electrode surfaces (e.g. Au, Pt or Ag) has been intensively studied
[4–9]. These studies were followed by investigations of the adsorption process of
small, water-soluble, redox-inactive molecules on electrode surfaces [3, 10–18]. The
process of adsorption of ions and molecules on the electrode surface may be
understood at the molecular level, when structure analyzing techniques are applied
to the electrochemical interface. Since the first application of PM IRRAS to the
electrochemical interface [19] the picture of potential-dependent changes in the
structure, composition, and orientation of molecules present on metallic electrode
surfaces is available in the literature.
3.1 Adsorption of Inorganic Ions on Metal Electrode
Surfaces: First Application of PM IRRAS
with Electrochemical Control
In 1984 Kunimatsu et al. [20] published the results of the first in situ PM IRRAS
study of the adsorption of inorganic ions on a metallic electrode surface. In this work
the adsorption of cyanide ions from 0.1 M KCN in 1 M K 2 SO 4 electrolyte solution
on the Ag electrode was investigated. Figure 3.1 shows the PM IRRA spectra in the
ν(CN) stretching mode spectral region at potentials marked in the figure.
© Springer Nature Switzerland AG 2020
I. Brand, Application of Polarization Modulation Infrared Reflection Absorption
Spectroscopy in Electrochemistry, Monographs in Electrochemistry,
https://doi.org/10.1007/978-3-030-42164-9_3
47
In Situ PM IRRAS Studies
of Redox-Inactive Molecular Films
Adsorbed on Electrodes
Adsorption of ions or neutral molecules on electrode surfaces leads to changes in the
macroscopic properties of surfaces such as the surface energy, contact angle, surface
charge density or surface potential. Potential-dependent adsorption-desorption process of ions or neutral molecules on electrode surfaces belongs to an important
research topic in electrochemistry. Some ions have the ability to adsorb specifically
on electrode surfaces, influencing the surface charge density and surface energy of
the electrode|electrolyte interface [1–3]. The phenomenon of specific adsorption of
ions on metallic electrode surfaces (e.g. Au, Pt or Ag) has been intensively studied
[4–9]. These studies were followed by investigations of the adsorption process of
small, water-soluble, redox-inactive molecules on electrode surfaces [3, 10–18]. The
process of adsorption of ions and molecules on the electrode surface may be
understood at the molecular level, when structure analyzing techniques are applied
to the electrochemical interface. Since the first application of PM IRRAS to the
electrochemical interface [19] the picture of potential-dependent changes in the
structure, composition, and orientation of molecules present on metallic electrode
surfaces is available in the literature.
3.1 Adsorption of Inorganic Ions on Metal Electrode
Surfaces: First Application of PM IRRAS
with Electrochemical Control
In 1984 Kunimatsu et al. [20] published the results of the first in situ PM IRRAS
study of the adsorption of inorganic ions on a metallic electrode surface. In this work
the adsorption of cyanide ions from 0.1 M KCN in 1 M K 2 SO 4 electrolyte solution
on the Ag electrode was investigated. Figure 3.1 shows the PM IRRA spectra in the
ν(CN) stretching mode spectral region at potentials marked in the figure.
© Springer Nature Switzerland AG 2020
I. Brand, Application of Polarization Modulation Infrared Reflection Absorption
Spectroscopy in Electrochemistry, Monographs in Electrochemistry,
https://doi.org/10.1007/978-3-030-42164-9_3
47