143
activity in between of Pt ML /Pd/C and Pt ML /Au/C, which also suggested a tunable
activity can be obtained from Pt ML by manipulating its lateral strain.
In situ infrared reflection absorption spectroscopy (IRRAS) study was carried
out to identify the reaction intermediates and products during methanol and ethanol
oxidation on Pt ML /Au(111), to gain insights into the substrate-induced change in the
selectivity of Pt ML , and into the mechanism of the greatly enhanced reaction kinetics. Figure 8.32 displays in situ IRRAS spectra during ethanol oxidation. The main
feature was the absence of both the CO ads and CO 2 bands (see Table 8.5), denoting
that ethanol dissociative adsorption on Pt ML /Au(111) did not occur and that the EOR
followed the partial oxidation pathway without cleavage of the C-C bond. Therefore,
the high ethanol oxidation reaction (EOR) activity on Pt ML /Au(111) was ascribed to
the fast kinetics of partial oxidation pathway generating acetic acid and acetaldehyde. The complete oxidation of ethanol requires full dehydrogenation and C-C
bond splitting, which might not be favored on stretched Pt ML on Au(111). However,
Brankovic and Strasser et al. [45] found a compete oxidation of ethanol on Pt ML on
Au nanoparticles, which was confirmed by Li et al. [44].
A significant enhancement in the EOR was found in Pt/Rh/SnO 2 ternary catalyst,
where Pt and Rh formed alloy nanoparticles (about 3 nm diameter) on top of larger
SnO 2 particles. It was found that the addition of Rh to Pt/SnO 2 bimetallic catalyst
enhances the catalysts’ selectivity in C-C bond splitting and CO 2 production during
the oxidation of ethanol [46].
Fig. 8.32 In situ IRRAS
spectra for identifying the
intermediates and products
of ethanol electrooxidation
on Pt ML /Au(111) in 0.1 M
HClO 4 containing 0.5 M
ethanol. One hundred
twenty-eight
interferograms (resolution
8 cm
−1
) were co-added to
each spectrum [44].
At open access at
Electrochemical Society.
8.4 Ethanol Electrooxidation on Platinum Monolayer Electrocatalysts
activity in between of Pt ML /Pd/C and Pt ML /Au/C, which also suggested a tunable
activity can be obtained from Pt ML by manipulating its lateral strain.
In situ infrared reflection absorption spectroscopy (IRRAS) study was carried
out to identify the reaction intermediates and products during methanol and ethanol
oxidation on Pt ML /Au(111), to gain insights into the substrate-induced change in the
selectivity of Pt ML , and into the mechanism of the greatly enhanced reaction kinetics. Figure 8.32 displays in situ IRRAS spectra during ethanol oxidation. The main
feature was the absence of both the CO ads and CO 2 bands (see Table 8.5), denoting
that ethanol dissociative adsorption on Pt ML /Au(111) did not occur and that the EOR
followed the partial oxidation pathway without cleavage of the C-C bond. Therefore,
the high ethanol oxidation reaction (EOR) activity on Pt ML /Au(111) was ascribed to
the fast kinetics of partial oxidation pathway generating acetic acid and acetaldehyde. The complete oxidation of ethanol requires full dehydrogenation and C-C
bond splitting, which might not be favored on stretched Pt ML on Au(111). However,
Brankovic and Strasser et al. [45] found a compete oxidation of ethanol on Pt ML on
Au nanoparticles, which was confirmed by Li et al. [44].
A significant enhancement in the EOR was found in Pt/Rh/SnO 2 ternary catalyst,
where Pt and Rh formed alloy nanoparticles (about 3 nm diameter) on top of larger
SnO 2 particles. It was found that the addition of Rh to Pt/SnO 2 bimetallic catalyst
enhances the catalysts’ selectivity in C-C bond splitting and CO 2 production during
the oxidation of ethanol [46].
Fig. 8.32 In situ IRRAS
spectra for identifying the
intermediates and products
of ethanol electrooxidation
on Pt ML /Au(111) in 0.1 M
HClO 4 containing 0.5 M
ethanol. One hundred
twenty-eight
interferograms (resolution
8 cm
−1
) were co-added to
each spectrum [44].
At open access at
Electrochemical Society.
8.4 Ethanol Electrooxidation on Platinum Monolayer Electrocatalysts