259
can be explained by host-guest interactions between 4-nitrophenol and
β-cyclodextrin.
In an attractive research, Li et al. (2014) benefited from the hybrid of
β-cyclodextrin and graphene nanosheets as a support for the synthesis of Pt nanoparticles. This hybrid material was prepared through a simple wet chemical method
which included the formation of graphene nanosheets-cyclodextrin material via
reduction of graphene in the presence of cyclodextrin and hydrazine followed by the
addition of PtCl 6
2and its subsequent reduction by sodium borohydride or formic
acid leading to a heterogeneous catalyst with a hydrangea-like morphology. The
authors believed that combination of cyclodextrin and graphene nanosheets could
furnish a support with high surface area, conductivity, and recognition property.
Noteworthy, the content of cyclodextrin was estimated to be 32 wt% which made
the hybrid system water soluble. The hybrid system was successfully used as an
electrocatalyst for the oxidation of MeOH with the catalytic activity and CO tolerance superior to those of conventional catalysts such as Pt/graphene nanosheets and
Pt/Vulcan X72R. The higher catalytic activity, which made this electrocatalyst very
promising for the use in direct methanol fuel cell, was attributed to the well dispersion of Pt nanoparticles and their specific morphologies.
Patil et al. (2018) prepared ruthenium nanoparticles supported on cyclodextrinmodified graphene oxide for the selective aerobic oxidation of alcohols in aqueous
medium but also in stilbene derivatives’ hydrogenation. NaBH 4 reduced both ruthenium precursor and graphene oxide in the presence of RaMe-β-cyclodextrin in a
one-pot strategy. RaMe-β-cyclodextrin not only acted as a capping agent for Ru
nanoparticles but also intercalated between the layers of graphene oxide and functionalized the surface of reduced graphene oxide by H bonding. The amount of
RaMe-β-cyclodextrin in rGO@Ru-RaMe-β-cyclodextrin was found to be 42.33 wt%
by thermogravimetric analysis when the amount of Ru, determined by ICP-AES
analysis, was about 2.5%. The best catalytic results related to the piperonyl alcohol
oxidation were obtained with rGO@Ru-RaMe-β-cyclodextrin in the presence of
K 2 CO 3 . After this optimization step, the catalyst was tested for a wide range of benzylic alcohols with various substituents such as Cl, NO 2 , NH 2 , or OMe. Yields ranging from 88% to 94% were obtained with selectivities higher than 99%. This
heterogeneous catalyst was also active in the reduction of several alkenes such as
stilbene and its derivatives. The recyclability of rGO@Ru-RaMe-β-cyclodextrin
was studied, and a slight decrease of the catalytic activity was observed after five
runs which could came from the leaching of Ru, confirmed by ICP-AES, and also
the leaching of RaMe-β-cyclodextrin, confirmed by thermogravimetric analysis.
The group of Montazer studied the influence of the amount of native β-cyclodextrin
in the synthesis of a nanocomposite. Ag/TiO 2 was prepared by addition of a solution
containing cyclodextrin and silver to a TiO 2 dispersion under irradiation (Attarchi
et al. 2013). They studied the influence of the amount of β-cyclodextrin, and according to dynamic light scattering experiments, the average hydrodynamic diameter in
water increased with the amount of cyclodextrin which was still present in the composite. The methylene blue photodegradation was studied with these composite
nanomaterials, and the reactivity was faster with Ag/TiO 2 /β-cyclodextrin (65% of
5 Metal Nanoparticles and Cyclodextrins for Catalytic Applications
can be explained by host-guest interactions between 4-nitrophenol and
β-cyclodextrin.
In an attractive research, Li et al. (2014) benefited from the hybrid of
β-cyclodextrin and graphene nanosheets as a support for the synthesis of Pt nanoparticles. This hybrid material was prepared through a simple wet chemical method
which included the formation of graphene nanosheets-cyclodextrin material via
reduction of graphene in the presence of cyclodextrin and hydrazine followed by the
addition of PtCl 6
2and its subsequent reduction by sodium borohydride or formic
acid leading to a heterogeneous catalyst with a hydrangea-like morphology. The
authors believed that combination of cyclodextrin and graphene nanosheets could
furnish a support with high surface area, conductivity, and recognition property.
Noteworthy, the content of cyclodextrin was estimated to be 32 wt% which made
the hybrid system water soluble. The hybrid system was successfully used as an
electrocatalyst for the oxidation of MeOH with the catalytic activity and CO tolerance superior to those of conventional catalysts such as Pt/graphene nanosheets and
Pt/Vulcan X72R. The higher catalytic activity, which made this electrocatalyst very
promising for the use in direct methanol fuel cell, was attributed to the well dispersion of Pt nanoparticles and their specific morphologies.
Patil et al. (2018) prepared ruthenium nanoparticles supported on cyclodextrinmodified graphene oxide for the selective aerobic oxidation of alcohols in aqueous
medium but also in stilbene derivatives’ hydrogenation. NaBH 4 reduced both ruthenium precursor and graphene oxide in the presence of RaMe-β-cyclodextrin in a
one-pot strategy. RaMe-β-cyclodextrin not only acted as a capping agent for Ru
nanoparticles but also intercalated between the layers of graphene oxide and functionalized the surface of reduced graphene oxide by H bonding. The amount of
RaMe-β-cyclodextrin in rGO@Ru-RaMe-β-cyclodextrin was found to be 42.33 wt%
by thermogravimetric analysis when the amount of Ru, determined by ICP-AES
analysis, was about 2.5%. The best catalytic results related to the piperonyl alcohol
oxidation were obtained with rGO@Ru-RaMe-β-cyclodextrin in the presence of
K 2 CO 3 . After this optimization step, the catalyst was tested for a wide range of benzylic alcohols with various substituents such as Cl, NO 2 , NH 2 , or OMe. Yields ranging from 88% to 94% were obtained with selectivities higher than 99%. This
heterogeneous catalyst was also active in the reduction of several alkenes such as
stilbene and its derivatives. The recyclability of rGO@Ru-RaMe-β-cyclodextrin
was studied, and a slight decrease of the catalytic activity was observed after five
runs which could came from the leaching of Ru, confirmed by ICP-AES, and also
the leaching of RaMe-β-cyclodextrin, confirmed by thermogravimetric analysis.
The group of Montazer studied the influence of the amount of native β-cyclodextrin
in the synthesis of a nanocomposite. Ag/TiO 2 was prepared by addition of a solution
containing cyclodextrin and silver to a TiO 2 dispersion under irradiation (Attarchi
et al. 2013). They studied the influence of the amount of β-cyclodextrin, and according to dynamic light scattering experiments, the average hydrodynamic diameter in
water increased with the amount of cyclodextrin which was still present in the composite. The methylene blue photodegradation was studied with these composite
nanomaterials, and the reactivity was faster with Ag/TiO 2 /β-cyclodextrin (65% of
5 Metal Nanoparticles and Cyclodextrins for Catalytic Applications