Biomedical Engineering Reference
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Besides, ILs unit could be attached to the sidewall of CNTs by
radical grafting, in which acid-oxidation pretreatment of CNTs could
be avoided. Chen et al. reported that thermal-initiation free radical
polymerization of the IL monomer 3-ethyl-1-vinylimidazolium
tetrafluoroborate ([VEIM]BF
) on the CNT surface (Fig. 4.18a) [62].
Then under similar method, the Pt and PtRu nanoparticles with
narrow size distribution (average diameter: (1.3
4
±
0.4) nm for PtRu,
±
(1.9
0.5) nm for Pt) are dispersed uniformly on the CNTs and
show better performance in methanol electrooxidation than that
without ILs units (Fig. 4.18b).
4.6 ILs-PROTECTED NANOSTRUCTURES AS
ELECTROCATALYSTS FOR SOME KEY REACTIONS
It was noted that without CNTs, very small Au NPs with an
average diameter 1.7 nm could be obtained, where the Au NPs
were presumably stabilized by amine-terminated ILs (Fig. 4.19a)
[63]. They could be kept stable without any special protection
and showed much better electrocatalysis toward reduction of
dioxygen (ORR) comparing with those stabilized by thiol or citrate
(Fig. 4.19b, c). Moreover, by further immobilizing IL-protected
Au NPs on carbon nanostructures, e.g., carbon nanotubes
or graphene nanosheets, by static interactions, the ORR current
increased up to 6 times, in which the unique electronic property
of carbon nanostructures as well as their large active surface
areas were believed to play key roles [64, 65]. Here, not only
Au NPs but also other noble metal NPs, such as Pt [66], and even
graphene nanosheets themselves (Fig. 4.20) [67] could be stabilized
by amine-terminated IL, and high electrocatalytic activity toward
ORR and oxidation of methanol was also observed.
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