Calixarene-mediated assembly of water-soluble C60-attached ultrathin graphite hybrids for efficient activation of reactive oxygen species to treat neuroblastoma cells

Unprecedented nano-carbon hybrids consisting of exfoliated ultrathin graphite (or single-walled carbon nanotubes) with pristine C₆₀ molecules attached on the surfaces have been produced in water in the presence of p-phosphonic acid calix[8]arene. The amphiphilic calixarene plays multiple roles in these processes to provide water dispersibility and π-π interactions with flexible conformations complementing curvatures of the carbon surfaces. The significantly increased water solubility and area of exposure of C₆₀ enable efficient activation of reactive oxygen species for enhanced phototoxicity to SH-SY5Y human neuroblastoma cell line under laser irradiation.

Calix[n]arene/Pillar[n]arene-Functionalized Graphene Nanocomposites and Their Applications

Calix[n]arenes and pillar[n]arenes, which contain repeating units of phenol and methane, are class of synthetic cyclic supramolecules. Their rigid structure, tunable cavity size, flexible functionalization, and rich host-guest properties make them ideal surface modifiers to construct functional hybrid materials. Introduction of the calix[n]arene/pillar[n]arene species to the graphene may bring new interesting or enhanced physicochemical/biological properties by combining their individual characteristics. Reported methods for the surface modification of graphene with calix[n]arene/pillar[n]arene utilize either covalent or non-covalent approaches. This mini-review presents the recent advancements in the functionalization of graphene nanomaterials with calix[n]arene/pillar[n]arene and their applications. At the end, the future outlook and challenges for the continued research of calix[n]arene/pillar[n]arene-functionalized graphene nanohybrids in the development of applied nanoscience are thoroughly discussed.

p-Phosphonic acid calix[8]arene mediated synthesis of ultra-large, ultra-thin, single-crystal gold nanoplatelets

Large, ultrathin, single-crystal gold platelets are produced in the presence of p-phosphonic acid calix[8]arene as both a catalyst and stabiliser.

One-pot synthesis of single-crystal Pt nanoplates uniformly deposited on reduced graphene oxide, and their high activity and stability on the electrocalalytic oxidation of methanol

We demonstrate a one-pot thermoreduction approach towards the preparation of single-crystal Pt nanoplates, which were uniformly deposited on the reduced graphene oxide (RGO) using polyvinylpyrrolidone (PVP) as a stabilizer. The size of Pt nanoplates can be tuned from 6.8 to 10.1 nm by controlling Pt loading. The as-prepared Pt/PVP/RGO catalysts show high stability and activity towards the methanol oxidation reaction (MOR). Their MOR current can reach up to 401 mA mg(-1) Pt and MOR current can maintain 89.4% of its initial value after 10 000 potential cycles.

Size-selective electrocatalytic activity of (Pt)n/MoS2 for oxygen reduction reaction

In the present work, we have investigated the electrocatalytic activity of the oxygen reduction reaction (ORR), O₂ + 4H⁺ + 4e⁻ → 2H₂O, for (Pt)_n clusters (n = 1, 2, 3, 5, 7, 10 and 12) adsorbed on semiconducting (2H) and metallic (1T) MoS₂ monolayers using first principles density functional theory.

Synthesis of graphene-supported one-dimensional nanoporous Pt based catalysts, and their enhanced performance on methanol electro-oxidation

A novel approach is developed to synthesize PtIr or Pt nanowires (NWs) supported on the reduced graphene oxide (RGO) using Te NWs as template based on the replacement reaction. The resulting RGO-supported PtIr and Pt electrocatalysts are characterized by transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy and electrochemical techniques. TEM images show that these Pt based catalysts are uniformly distributed in the matrix of graphene with a characteristic of one-dimensional (1D) nanoporous structure. As one of promising anode materials used in the direct methanol fuel cells, these 1D nanoporous PtIr/RGO (or Pt/RGO) hybrids exhibit an enlarged electroactive surface and enhanced catalytic activity toward the methanol reaction relative to those PtIr or Pt NWs without graphene support.

Continuous flow Fischer esterifications harnessing vibrational-coupled thin film fluidics

Organic synthesis under shear: high yielding, acid catalysed, continuous flow synthesis of esters involves coupling of vibrations in thin film fluidics, as rapid environmentally friendly organic methodology.

Facile synthesis of electrochemically active Pt nanoparticle decorated carbon nano onions

Well dispersed platinum nanoparticles (∼2 nm) on carbon nano-onions are accessible using a simple and scalable one-step batch method.

p-Phosphonic acid calix[8]arene assisted dispersion and stabilisation of pea-pod C60@multi-walled carbon nanotubes in water

Pristine C₆₀ and MWCNTs are non-covalently stabilised in water by p-phosphonic acid calix[8]arene, additionally with ‘pea-pod’ encapsulation of C₆₀ inside the MWCNTs.

Palladium nanoparticles on β-cyclodextrin functionalised graphene nanosheets: a supramolecular based heterogeneous catalyst for C–C coupling reactions under green reaction conditions

Palladium nanoparticles on β-cyclodextrin functionalised graphene based supramolecular heterogeneous catalyst are used for Suzuki–Miyaura and Heck–Mizoroki coupling reactions under green reaction conditions.

Amphiphilic graphene oxide stabilisation of hexagonal BN and MoS2 sheets

A simple and scalable method has been developed for directly forming water-dispersible heterolaminar solids involving mixing aqueous solution of amphiphilic graphene oxide with hexagonal boron nitride or molybdenum disulphide in N-methylpyrrolidone.

Facile preparation of ultralong dendritic PtIrTe nanotubes and their high electrocatalytic activity on methanol oxidation

A facile wet chemical approach was developed to prepare ultralong PtIrTe nanotubes (NTs) using Te nanowires (NWs) as template. These PtIrTe NTs were made up of Pt nanodendrites uniformly arrayed on the surface of IrTe NTs and interweaved with each other to nanopores. Their morphology, structure, and composition were investigated by transition electron microscopy, X-ray powder diffraction, and X-ray photoelectron spectroscopy. As expected, these PtIrTe NTs catalysts show a larger surface area, a stronger CO tolerance, and a higher catalytic activity toward electrochemical oxidation of methanol relative to the commercial Pt catalysts due to the 1D porous core-shell structure and the modification of the electronic effect by Ir.

Hydrogen induced p-phosphonic acid calix[8]arene controlled growth of Ru, Pt and Pd nanoparticles

Monodispersed Ru, Pt and Pd nanoparticles with narrow size distributions (2, 12 and 20 nm respectively) have been synthesised via bubbling hydrogen gas into aqueous solutions of the noble metal ions in the presence of p-phosphonic acid calix[8]arene, at room temperature. Molecular modelling of the Ru nanoparticles provides insight into the role of the calixarene in controlling the size and stabilisation of the metal nanoparticles.

Sonochemical fabrication of gold nanoparticles-boron nitride sheets nanocomposites for enzymeless hydrogen peroxide detection

A simple sonochemical route was developed for the preparation of gold nanoparticles/boron nitride sheets (AuNPs/BNS) nanocomposites without using reducing or stabilizing agents. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and UV-vis absorption spectra were used to characterize the structure and morphology of the nanocomposites. The experimental results showed that AuNPs with approximately 20nm were uniformly attached onto the BNS surface. It was found that the AuNPs/BNS nanocomposites exhibited good catalytic activity for the reduction of H2O2. The modified electrochemical sensor showed a linear range from 0.04 to 50mM with a detection limit of 8.3μM at a signal-to-noise ratio of 3. The findings provide a low-cost approach to the production of stable aqueous dispersions of nanoparticles/BNS nanocomposites.

Self-assembled calixarene aligned patterning of noble metal nanoparticles on graphene

Patterns of noble metal nanoparticles (NMNPs) of ruthenium and platinum are formed on p-phosphonic acid calix[8]arene stabilised graphene in water. This involves hydrogen gas induced reduction of metal ions absorbed on the stabilised graphene, with TEM revealing the patterns being comprised of domains of parallel arrays of NMNPs ∼7 nm apart. The domains are orientated in three directions on each graphene sheet at an angle of ∼60° or ∼120° with respect to each other. AFM of self-assembled p-phosphonic acid calix[8]arene on the surface of a highly ordered pyrolytic graphite (HOPG) revealed a similar pattern, implying that the orientation of the assembly of p-phosphonic acid calix[8]arene is governed by the hexagonal motif of graphite/graphene.

Nitrate uptake by p-phosphonic acid or p-(trimethylammonium)methyl calix[8]arene stablized laminar materials

Graphite, BN, MoS₂ and WS₂ are exfoliated and stablized in water with positively or negatively charged non-toxic calix[8]arenes. All 2D materials adsorb nitrate from waste effluent, precipitating once nitrate is bound, and can be regenerated.

Continuous flow vortex fluidic production of biodiesel

Vortex fluidic synthesis of biodiesel from sunflower oil under continuous flow at room temperature, with spontaneous phase separation.

Shear flow assisted decoration of carbon nano-onions with platinum nanoparticles

Aqueous based controlled decoration of platinum nanoparticles on plasma treated carbon nano-onions (CNOs) occurs within the shear flow generated by a vortex fluidic device (VFD), using ascorbic acid as the reducing agent, with the electrocatalytic potential of the resulting Pt-NPs@CNOs nano-composites demonstrated.