Cyclodextrin Functionalized Graphene Nanosheets with High Supramolecular Recognition Capability: Synthesis and Host−Guest Inclusion for Enhanced Electrochemical Performance

Abstract

Cyclodextrins (CDs) are oligosaccharides composed of six, seven, or eight glucose units (alpha-, beta-, or gamma-CD, respectively), which are toroidal in shape with a hydrophobic inner cavity and a hydrophilic exterior. These interesting characteristics can enable them to bind selectively various organic, inorganic and biological guest molecules into their cavities to form stable host-guest inclusion complexes or nanostructured supramolecular assemblies in their hydrophobic cavity. On the other hand graphene nanosheet (GN), a rising-star material, holds great promise for potential applications in many technological fields due to its high surface areas, low cost, and high conductivity. If GNs are modified with CDs, it is possible to obtain new materials simultaneously possessing unique properties of GNs and cyclodextrins through combining their individual obvious advantages. In this article, we demonstrate for the first time a simple wet-chemical strategy for the preparation of CD-graphene organic-inorganic hybrid nanosheets (CD-GNs), which exhibited high solubility and stability in polar solvent. The obtained CD-GNs were characterized by UV-vis spectroscopy, static contact angle measurement, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy, which confirmed that CD had been effectively functionalized on the surface of GNs. Furthermore, the formation mechanism of CD-GNs was also discussed. Interestingly, GNs here could load a number of CD molecules, which was very important for greatly enhancing the supramolecular function of CDs. Electrochemical results obviously reveal that CD-graphene organic-inorganic hybrid nanosheets could exhibit very high supramolecular recognition and enrichment capability and show much higher electrochemical response toward eight probe molecules (biomolecules and drugs) than unmodified GNs and carbon nanotubes, which is probably caused by the synergetic effects from GNs (high conductivity and high surface area) and CD molecules (host-guest recognition and enrichment).

CuO Nanorods-Decorated Reduced Graphene Oxide Nanocatalysts for Catalytic Oxidation of CO

“…Figure 2 shows the Raman spectrum of the RGO-CuO hybrid nanocatalysts with different RGO contents. From Figure 2, one can see that the broad peaks displayed at 1350 and 1575 cm −1 are assigned to the D band (κ-point phonons of A 1g symmetry) and G band (E 2g phonon of C sp 2 atoms) [30], which confirm the presence of graphene in the hybrid composites. In addition, there are two typical peaks at around 343 and 640 cm −1 observed for the RGO-CuO hybrid nanocatalysts, which are characteristics of a CuO phase [22,31].…”

Adsorption of hexavalent chromium ions from aqueous solution by graphene nanosheets: kinetic and thermodynamic studies

“…1). The bands at 3421, 1565, and 1196 cm -1 are attributed to O-H stretching vibrations of adsorbed water molecules and structural OH groups (Lian et al 2010), the skeletal vibration of graphene nanosheets (Guo et al 2009), and C-C band (Guo et al 2010), respectively.…”

Reduced Graphene Oxide/α-Cyclodextrin-Based Electrochemical Sensor: Characterization and Simultaneous Detection of Adenine, Guanine and Thymine

“…Furthermore, aromatic C=C stretching modes at 1630, 1671 and 1642 cm -1 belongs to GO, rGO and rGO/α-CD, respectively [5]. The characteristic stretching vibrational modes of C=O (1731 cm -1 ), C-O (1219 cm -1 ) and C-O (1051 cm -1 ) bonds were observed in GO spectrum.…”

“…Then, rGO/α-CD nanosheets were obtained by following the previously reported procedure [5]. Briefly, a 40.0 mL of GO dispersion (0.5 mg mL -1 ) was sonicated for 1 h. After that, 40.0 mL of 160 mg mL -1 of α-CD aqueous solution and 600.0 µL of ammonia solution were transferred to the GO solution.…”

“…With its unique features, graphene is considered as an excellent supporting material and it has attracted a great attention of researchers in both academic and industrial fields [2,4]. In recent years, a great interest has grown for investigation of graphene and related materials having various new characteristics by either covalent/non-covalent interactions of metal nanoparticles, polymers or toroidal-shaped macromolecules such as cyclodextrins [5][6][7][8]. Cyclodextrins (CDs) are oligosaccharides (α-, β-, or γ-CD) with a lipophilic inner cavity and a hydrophilic outer surface [9].…”