spectral features originate from the water vibrations (around 1700 cm
À1 ) and CO 2
vibrations (around 2345 cm
À1 ). Figure 4.12 shows the R.F. surface and R.F. bulk spectra
calculated using Eqs. (4.7) and (4.8). Large differences are observed between the
calculated R.F. surface and R.F. bulk spectra for ethanol electrooxidation at E ¼ À0.3 V
at time t ¼ 0 min and t ¼ 10 min (Fig. 4.12). Changes in the spectral features indicate
that the electrooxidation of ethanol is a complex reaction in which different chemical
species are produced.
Differences between the R.F. surface and R.F. bulk spectra indicate that the composition of the species present on the electrode-catalyst surface differs from the species
0.2
0.1
Sam_0 min
Sam_10 min
Sam_0 min
Sam_10 min
Pd/CeO 2
Pd/CeO 2
0.0
–0.1
–0.2
0.1
0.0
3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200
Wavenumber / cm
-1
3400 3200 3000 2800 2600 2400 2200 2000 1800 1600 1400 1200
Wavenumber / cm
-1
R.F.
(surf)
R.F.
(bulk)
CO 2
C-H
C=O
OC=O
Fig. 4.12 PM IRRAS (a) R.F. surface and (b) R.F. bulk spectra for ethanol electrooxidation on
Pd/CeO 2 nanoparticles on the GCE in 1 M ethanol and KOH solution. Copied with permission
from [19]
112
4 In Situ PM IRRAS Studies of Redox-spi1;Active Molecular Films...