present in the solution layer. After 10 min of the ethanol electrooxidation reaction
new IR absorption bands appear in the R.F. surface spectrum. Two strong IR absorption modes at 1560 and 1423 cm
À1 (Fig. 4.12a) are assigned to ν as (COO
À ) and
ν s (COO
À
) modes. This result indicates that the electrooxidation of ethanol leads to
the formation of acetate ions, which accumulate on the surface of the Pd/CeO 2 NPs.
A weak IR absorption mode at 2345 cm
À1 indicates that CO 2 is another product of
the ethanol oxidation reaction. With elapsing time a negative broad absorption band
in the 3000–2800 cm
À1 spectral region appears in the spectra (Fig. 4.12a). It is
assigned to the CH stretching modes in ethanol. A negative sign of the CH stretching
modes indicates that ethanol is consumed in the reaction and its content on the
surface decreases. The R.F. bulk spectrum (Fig. 4.12b) reveals the presence of the
ν(C¼O) modes in CO 2 (2345 cm
À1 ) and in ketone (1724 cm
À1 ) species. The two
ν as (COO
À ) and ν s (COO
À
) modes are seen in the R.F. bulk spectrum, indicating that
the carboxylate species are also present in the electrolyte solution. The ν(C¼O)
mode in CO 2 is significantly stronger in the bulk than in the surface spectrum,
indicating that CO 2 formed on the electrode surface is immediately desorbed into the
solution phase. This example illustrates clearly that the proceeding of the PM IRRA
proposed by Monyoncho provides information about the dynamics of complex
redox reactions and may become a useful analytical tool to detect in situ structural
changes occuring during complex redox reactions directly on the electrode surface as
well as in the solution phase [18, 19]. This approach extends the applicability of PM
IRRAS with electrochemical control to thick disordered films, making this excellent
technique very attractive for wide applications in electrochemistry.
References
1. Golden WG, Kunimatsu K, Seki H (1984) Application of polarization-modulated Fourier
transform infrared reflection-absorption spectroscopy to the study of carbon monoxide adsorption and oxidation on a smooth platinum electrode. J Phys Chem 88:1275–1277
2. Brand I, Juhaniewicz J, Verani CN, Wickramasinghe L (2018) An in situ
spectroelectrochemical study on the orientation changes of an [Fe
III
L
N2O3 ] metallosurfactant
deposited as LB films on gold electrode surfaces. Dalton Trans 47:14218–14226
3. Tagliazucchi M, Méndez De Leo LP, Cadranel A, Baraldo LM, Völker E, Bonazzola C, Calvo
EJ, Zamlynny V (2010) PM IRRAS spectroelectrochemistry of layer-by-layer self-assembled
polyelectrolyte multilayers. J Electroanal Chem 649:110–118
4. Hosseini P, Wittstock G, Brand I (2018) Infrared spectroelectrochemical analysis of potential
dependent changes in cobalt hexacyanoferrate and copper hexacyanoferrate films on gold
electrodes. J Electroanal Chem 812:199–206
5. Roberts G (1990) Langmuir–Blodgett films. Plenum, New York
6. Allard MM, Sonk JA, Heeg MJ, McGarvey BR, Schlegel HB, Verani CN (2012) Bioinspired
five-coordinate iron(III) complexes for stabilization of phenoxyl radicals. Angew Chem Int Ed
51:3178–3182
7. Wickramasinghe LD, Mazumder S, Kpogo KK, Staples RJ, Schlegel HB, Verani CN (2016)
Electronic modulation of the SOMO–HOMO energy gap in iron(III) complexes towards
unimolecular current rectification. Chem Eur J 22:10786–10790
References
113
new IR absorption bands appear in the R.F. surface spectrum. Two strong IR absorption modes at 1560 and 1423 cm
À1 (Fig. 4.12a) are assigned to ν as (COO
À ) and
ν s (COO
À
) modes. This result indicates that the electrooxidation of ethanol leads to
the formation of acetate ions, which accumulate on the surface of the Pd/CeO 2 NPs.
A weak IR absorption mode at 2345 cm
À1 indicates that CO 2 is another product of
the ethanol oxidation reaction. With elapsing time a negative broad absorption band
in the 3000–2800 cm
À1 spectral region appears in the spectra (Fig. 4.12a). It is
assigned to the CH stretching modes in ethanol. A negative sign of the CH stretching
modes indicates that ethanol is consumed in the reaction and its content on the
surface decreases. The R.F. bulk spectrum (Fig. 4.12b) reveals the presence of the
ν(C¼O) modes in CO 2 (2345 cm
À1 ) and in ketone (1724 cm
À1 ) species. The two
ν as (COO
À ) and ν s (COO
À
) modes are seen in the R.F. bulk spectrum, indicating that
the carboxylate species are also present in the electrolyte solution. The ν(C¼O)
mode in CO 2 is significantly stronger in the bulk than in the surface spectrum,
indicating that CO 2 formed on the electrode surface is immediately desorbed into the
solution phase. This example illustrates clearly that the proceeding of the PM IRRA
proposed by Monyoncho provides information about the dynamics of complex
redox reactions and may become a useful analytical tool to detect in situ structural
changes occuring during complex redox reactions directly on the electrode surface as
well as in the solution phase [18, 19]. This approach extends the applicability of PM
IRRAS with electrochemical control to thick disordered films, making this excellent
technique very attractive for wide applications in electrochemistry.
References
1. Golden WG, Kunimatsu K, Seki H (1984) Application of polarization-modulated Fourier
transform infrared reflection-absorption spectroscopy to the study of carbon monoxide adsorption and oxidation on a smooth platinum electrode. J Phys Chem 88:1275–1277
2. Brand I, Juhaniewicz J, Verani CN, Wickramasinghe L (2018) An in situ
spectroelectrochemical study on the orientation changes of an [Fe
III
L
N2O3 ] metallosurfactant
deposited as LB films on gold electrode surfaces. Dalton Trans 47:14218–14226
3. Tagliazucchi M, Méndez De Leo LP, Cadranel A, Baraldo LM, Völker E, Bonazzola C, Calvo
EJ, Zamlynny V (2010) PM IRRAS spectroelectrochemistry of layer-by-layer self-assembled
polyelectrolyte multilayers. J Electroanal Chem 649:110–118
4. Hosseini P, Wittstock G, Brand I (2018) Infrared spectroelectrochemical analysis of potential
dependent changes in cobalt hexacyanoferrate and copper hexacyanoferrate films on gold
electrodes. J Electroanal Chem 812:199–206
5. Roberts G (1990) Langmuir–Blodgett films. Plenum, New York
6. Allard MM, Sonk JA, Heeg MJ, McGarvey BR, Schlegel HB, Verani CN (2012) Bioinspired
five-coordinate iron(III) complexes for stabilization of phenoxyl radicals. Angew Chem Int Ed
51:3178–3182
7. Wickramasinghe LD, Mazumder S, Kpogo KK, Staples RJ, Schlegel HB, Verani CN (2016)
Electronic modulation of the SOMO–HOMO energy gap in iron(III) complexes towards
unimolecular current rectification. Chem Eur J 22:10786–10790
References
113