Process parameter optimisation for endohedral metallofullerene synthesis via the arc-discharge method

Fullerenes have a unique structure, capable of both encapsulating other molecules and reacting with those on the exterior surface. Fullerene derivatives have also been found to have enormous potential to address the challenges of the renewable energy sector and current environmental issues, such as in the production of n-type materials in bulk heterojunction solar cells, as antimicrobial agents, in photocatalytic water treatment processes, and in sensor technologies. Endohedral metallofullerenes, in particular, can possess unpaired electron spins, driven by the enclosed metal atom or cluster, which yield valuable magnetic properties. These properties have significant potential for applications in molecular magnets, spin probes, quantum computing, and devices such as quantum information processing,, atomic clocks, and molecular magnets. However, the intrinsically low yield of endohedral fullerenes remains a huge obstacle, impeding not only their industrial utilization but also the synthesis and characterization essential for exploring novel applications. The low yield and difficulty in separation of different types of endohedral fullerenes results in the usage of a large amount of solvents and energy, which is detrimental to the environment. In this paper, we analyse the methodologies proposed by various researchers and identify the critical synthesis parameters that play a role in increasing the yields of fullerenes

Long stokes shifts and vibronic couplings in perfluorinated polyanilines

We report the effect of surfactant addition on the optical properties of perfluorinated polyanilines synthesized through liquid–liquid interfaces. We obtained very long Stokes shifts, 205 nm, for oligomers derived from a hydrofluoroether–water system in the presence of Triton X-100 as a surfactant, and vibronic fine features from a toluene-water system

Redox-dependent Franck–Condon blockade and Avalanche Transport in a Graphene–Fullerene single-molecule transistor

We report transport measurements on a graphene–fullerene single-molecule transistor. The device architecture where a functionalized C60 binds to graphene nanoelectrodes results in strong electron–vibron coupling and weak vibron relaxation. Using a combined approach of transport spectroscopy, Raman spectroscopy, and DFT calculations, we demonstrate center-of-mass oscillations, redox-dependent Franck–Condon blockade, and a transport regime characterized by avalanche tunnelling in a single-molecule transistor

European Survey on Scholarly Practices and Digital Needs in the Arts and Humanities

This report summarizes the statistical analysis of the findings of a web-based survey conducted by the Digital Methods and Practices Observatory (DiMPO), a working group under VCC2 of the DARIAH research infrastructure (Digital Research Infrastructure for the Arts and Humanities). In order to provide an evidence-based, up-to-date, and meaningful account of the emerging information practices, needs and attitudes of arts and humanities researchers in the evolving European digital scholarly environment, the web survey involved a transnational team of researchers from more than a dozen countries, and addressed digitally-enabled research practices, attitudes and needs in all areas of Europe and across different arts and humanities disciplines and contexts

Photocatalytic H-2 evolution, CO2 reduction, and NOx oxidation by highly exfoliated g-C3N4

g-C3N4, with specific surface area up to 513 m(2)/g, was prepared via three successive thermal treatments at 550 degrees C in air with gradual precursor mass decrease. The obtained bulk and exfoliated (1ex, 2ex and 3ex) g-C3N4 were characterized and tested as photocatalysts for H-2 production, CO2 reduction and NOx oxidation. The exfoliated samples demonstrated graphene-like morphology with detached (2ex) and sponge-like framework (3ex) of layers. The surface area increased drastically from 20 m(2)/g (bulk) to 513 m(2)/g (3ex). The band gap (E-g) increased gradually from 2.70 to 3.04 eV. Superoxide radicals (O-center dot(2)-) were mainly formed under UV and visible light. In comparison to the bulk, the exfoliated g-C3N4 demonstrated significant increase in H-2 evolution (similar to 6 times), CO2 reduction (similar to 3 times) and NOx oxidation (similar to 4 times) under UV light. Despite the E-g widening, the photocatalytic performance of the exfoliated g-C3N4 under visible light was improved too. The results were related to the large surface area and low e(-)-h(+) recombination. The highly exfoliated g-C3N4 demonstrated selectivity towards H-2 evolution reactions.Web of Science1010art. no. 114

Electrochemically active water repelling perfluorinated polyaniline films

Water repelling, perfluorinated, polyanilines and their composites with multi-wall carbon nanotubes are synthesized using interfacial polymerization in either flake-like or fibrillar shapes. This class of polyanilines exhibits electrochemical activity, capacitive behaviour, and a contact angle of 119–125° with water. The addition of multi-wall carbon nanotubes facilitates the control of the polymer morphology and increases the specific capacitance of the material. We obtained microfibers or flake-like morphologies depending on the amount of multiwall carbon nanotubes added in the organic phase and through cyclic voltammetry, impedance spectroscopy and galvanostatic charge-discharge, we evaluated the effect of the backbone geometry and the addition of nanotubes on the electrochemical properties of the composites and the pristine polymers. The capacitance of the linear 3-perfluoroctyl polyaniline is consistently better than the cross-linked 4-perfluoroctyl polyaniline, where the para position relative to the amine group is blocked by fluorocarbon chains

Fullerol ionic fluids

http://pubs.rsc.org/en/Content/ArticlePDF/2010/NR/C0NR00307G/2010-06-08?page=SearchWe report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine(R)). The ionic fluid was compared to a control synthesized by mixing the parially protonated from (sodium form) of hte fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine (R) (liquid-like) and the control (solid-like).This publication is based on work supported in part by Award No. KUS-C1-018-02 made by King Abdullah University of Science and Technology (KAUST)

Ultra-stiff large-area carpets of carbon nanotubes

Herewith, we report the influence of post-synthesis heat treatment (≤2350 °C and plasma temperatures) on the crystal structure, defect density, purity, alignment and dispersibility of free-standing large-area (several cm2) carpets of ultra-long (several mm) vertically aligned multi-wall carbon nanotubes (VA-MWCNTs). VA-MWCNTs were produced in large quantities (20–30 g per batch) using a semi-scaledup aerosol-assisted chemical vapour deposition (AACVD) setup. Electron and X-ray diffraction showed that the heat treatment at 2350 °C under inert atmosphere purifies, removes residual catalyst particles, and partially aligns adjacent single crystals (crystallites) in polycrystalline MWCNTs. The purification and improvement in the crystallites alignment within the MWCNTs resulted in reduced dispersibility of the VA-MWCNTs in liquid media. High-resolution microscopy revealed that the crystallinity is improved in scales of few tens of nanometres while the point defects remain largely unaffected. The heat treatment also had a marked benefit on the mechanical properties of the carpets. For the first time, we report compression moduli as high as 120 MPa for VA-MWCNT carpets, i.e. an order of magnitude higher than previously reported figures. The application of higher temperatures (arc-discharge plasma, ≥4000 °C) resulted in the formation of a novel graphite–matrix composite reinforced with CVD and arc-dischargelike carbon nanotubes