Zirconium Cage-Doped Fullerenes

Abstract

Some zirconium containing fullerenes were synthesized by vaporizing a zirconium-containing graphite anode with DC arc discharge technique, extracted by CS2 through low temperature extraction method, and characterized by field desorption mass spectra (FDMS). The results show that these doped fullerenes were zirconium cage-doped fullerenes.     

电弧法制备洋葱状富勒烯的工艺研究

运用纳米Bi2O3微粒作催化剂，在电弧放电条件下，进行了纳米洋葱状富勒烯大量合成的研究。并用透射电镜对产物的形貌、结构进行了观察与分析。结果表明：纳米洋葱状富勒烯的石墨化程度很高，且直径均匀(约为25nm)，结构较完善；同时伴有单核纳米洋葱状富勒烯向多核纳米洋葱状富勒烯的转变。为洋葱状富勒烯的宏量制备提供了有利线索。     

内嵌放射性金属同位素富勒烯的制备及生物学研究

综述了内嵌放射性金属同位素富勒烯的制备及医用研究现状。内嵌金属富勒烯的制备目前主要采用电弧放电法,但产率还较低;而放射性内嵌金属富勒烯的合成,主要是利用镧系区域的钬、钐和镥等具有合适的中子捕获截面及适当的半衰期的元素首先由电弧法制备,然后在中子的辐照下形成。因中子辐照会破坏碳笼,故放射性内嵌金属富勒烯的产率更低。动物实验是利用BALB/c小鼠和Fischer大鼠进行活体代谢实验,结果表明,放射性钬内嵌金属富勒烯主要分布于骨骼和肝脏,毒性低而靶向性高。放射性内嵌金属富勒烯有望成为新型放射性药物或示踪剂。     

金属氮化物富勒烯的研究现状

内嵌金属氮化物簇富勒烯的发现极大地扩展了内嵌富勒烯家族。内嵌金属氮化物富勒烯是一类将含有金属原子的氮化物(Mx-N,AxM3-x-N)包裹在富勒烯碳笼中的化合物,因其具有独特的分子结构和性质而受到人们广泛的研究和关注。阐述了合成金属氮化物富勒烯的方法,着重介绍了电弧法,探讨了氮源对电弧法合成金属氮化物富勒烯产量的影响,介绍了金属氮化物富勒烯常用的分离提纯方法,最后讨论了金属氮化物富勒烯的结构特点、性质和潜在应用。     

Ordered fullerene nanocylinders in large-diameter carbon nanotubes

A new ordered fullerene phase encapsulated by large-diameter CNTs is systematically investigated by combining a growth technique by chemical vapour deposition, high-resolution transmission electron microscopy and molecular-dynamics simulations. In contrast to fullerenes in smaller (1-2?nm) diameter CNTs, where fullerenes are packed in linear or helical chains, fullerenes form a nanoscale cylinder in double-walled CNTs with diameters of ～4?nm. The fullerenes were shown to form a nanocylinder with a side wall that resembled the (111) plane of solid C(60). This ordered phase is different from peapods or fullerene solids known so far, and a result of the interaction between the CNT wall and fullerenes. This finding will open up a new field of fullerene science.     

Synthesis of fullerenes from carbon powder by using high power induction thermal plasma

Radio frequency (rf) inductively coupled thermal plasma (ICTP) was used to fabricate fullerenes (C₆₀,C₇₀, etc.) by direct evaporation of carbon powder injected into the plasma. Spectroscopic observation of the plasma was made for molecular band spectra of C₂ and atomic lines of C. The formation of fullerenes C₆₀ and C₇₀ as well as higher fullerenes were checked and recognized by high performance liquid chromatography (HPLC) and time-of-flight mass spectrometer (TFMS). The suitable conditions for the synthesis of fullerenes within the experimental conditions adopted were 10-kPa plasma pressure, with a considerably higher flow rate of approximately 150 l/min for mixed-gas condition of Ar, He and CO₂, with carbon powder of average diameter 20 μm. The results showed that the productivity of fullerenes has a relation to the intensity of C₂ molecular and C atomic spectra from the induction plasma. Mixing of Si with C particles has a kind of role in enhancing the synthesis rate of fullerenes C₆₀, as well as the higher order fullerenes.     

Structural and electronic properties of C and BN nanotubes based on periodic fullerenes: A density functional theory study

The structural and electronic properties of C and BN nanotubes based on periodic fullerenes were studied using density functional theory. It was shown that these tubular structures are stable. The electronic band structures and density of states indicated that the C nanotubes based on periodic fullerenes are metals. The energy band gap was appeared by substitution of C atoms with B and N atoms. The BN nanotubes based on periodic fullerenes show semiconducting properties. Our results suggest that the nanotubes based on periodic fullerenes can be used to design of nanoelectronic devices.     

Extraction of Exotic Fullerenes and Purification of Single-Walled Nanotubes

In this report, we presented a novel and simple extraction method, namely Hydrothermally Initiated Dynamic Extraction (HIDE) method, which allows the extraction of exotic fullerenes remaining in the fullerene soot. In the HIDE method, the soot was treated in boiling water that neither dissolved fullerenes nor produced minimal by-products but untangles the fullerenes from the soot, prior to the extraction by organic solvent. As a result, the HIDE method allowed the extraction of exotic fullerenes, such as dimeric fullerene oxides, higher fullerenes having a low symmetry and oxidized higher fullerenes. Accordingly, the single walled nanotubes (SWNTs) with a purity of 99% by wt was achieved for the first time with the application of the HIDE method.     

Synthesis of C60-NBN and C70-NBN(N=L, 2) by DC arc Burning Method

Macroscopic quantities of boron-doped fullerenes, such as C_60-nB_n and C_70-nB_n(n = 1, 2), were successfully synthesized by DC arc burning method, extracted by CS₂, and characterized by field desorption mass spectra. Among them C₅₈B₂ and C₆₈B₂ were extracted for the first time. The boron-doped fullerenes were found to be less stable than their pristine fullerene analogs. When the electric current becomes too high, no boron doped fullerene, but more higher fullerenes, were formed.     

富勒烯制备方法研究的进展

评述了近几年来富勒烯物质的发展过程。论述了不同形态的富勒烯的各种制备方法及其提纯分离工艺,并对各种制备工艺进行了分析和探讨性研究,在此基础眩指出了每种方法的优缺点,就富勒烯的基础研究、宏量制备和应用研究提出了一些看法,并简述了本研究小组采用电子束辐照法,金属纳米微粒诱发催化非晶炭膜转变成泮葱头状富富勒烯的工作。     

A novel hybrid carbon material

Both fullerenes and single-walled carbon nanotubes (SWNTs) exhibit many advantageous properties. Despite the similarities between these two forms of carbon, there have been very few attempts to physically merge them. We have discovered a novel hybrid material that combines fullerenes and SWNTs into a single structure in which the fullerenes are covalently bonded to the outer surface of the SWNTs. These fullerene-functionalized SWNTs, which we have termed NanoBuds, were selectively synthesized in two different one-step continuous methods, during which fullerenes were formed on iron-catalyst particles together with SWNTs during CO disproportionation. The field-emission characteristics of NanoBuds suggest that they may possess advantageous properties compared with single-walled nanotubes or fullerenes alone, or in their non-bonded configurations.     

Extraction of Exotic Fullerenes and Purification of Single-Walled Nanotubes

Abstract

In this report, we presented a novel and simple extraction method, namely Hydrothermally Initiated Dynamic Extraction (HIDE) method, which allows the extraction of exotic fullerenes remaining in the fullerene soot. In the HIDE method, the soot was treated in boiling water that neither dissolved fullerenes nor produced minimal by-products but untangles the fullerenes from the soot, prior to the extraction by organic solvent. As a result, the HIDE method allowed the extraction of exotic fullerenes, such as dimeric fullerene oxides, higher fullerenes having a low symmetry and oxidized higher fullerenes. Accordingly, the single walled nanotubes (SWNTs) with a purity of 99% by wt was achieved for the first time with the application of the HIDE method.     

巴基葱及其电学特性研究

利用直流弧光放电法制备了巴基葱,高分辨透射电子显微镜分析表明这种巴基葱为空心椭球形,由11层富勒烯组成。利用超高真空原子力显微镜和扫描隧道显微镜研究了巴基葱在高定向石墨基底上的行为和电学特性。巴基葱的扫描隧道谱结果表明,巴基葱的电学特性介于石墨和单层富勒烯之间。     

New Approach in Synthesis of Carbon Allotropes in Large Quantities

This work proposes a new method for mass production of carbon allotropes synthesis by arc-plasma. In particular, carbon vapor is produced from graphite electrode by introducing a buffer gas into the electrode gap to generate an intense gas outflow and fast evacuation of the produced vapor from the hot plasma zone. Study of the influence of the gas flow dynamics differently supplied to the hot plasma zone during the fullerenes synthesis was studied and the relationships between different gas flow rates, applied power, diameters of used electrodes and fullerenes productivity and yield were established. The new proposed method allows a significant increase of fullerenes productivity.     

Interaction between fullerenes and single-wall carbon nanotubes: the influence of fullerene size and electronic structure

A series of fullerenes and endohedral metallofullerenes peapods have been synthesized by supercritical method in high filling rate. The interaction between SWNTs and various kinds of fullerenes (C60, C70, C78, C84) and metallofullerenes (Gd@C82, Er@C82, Ho@C82, Y@C82) has been further investigated. The slight blue shift of G-band in Raman spectra with respect to pristine SWNTs was attributed to the charge transfer from SWNTs to fullerenes cage. The obvious RBM shift strongly depended on the distance between the inner wall of the SWNTs and the fullerene cage and also partly associated with the electronic structure of the fullerene. These results indicated that the interaction between fullerenes and SWNTs, which was considered to be the van de walls interaction, can be influenced by the cage size and the kind of fullerenes.     

Synthesis of zirconium diboride–zirconium nitride composite powders by self-propagating high-temperature synthesis

Formation of zirconium diboride–zirconium nitride composite powders by self propagating high temperature reaction of zirconium, boron and hexagonal boron nitride powders was investigated. Zirconium diboride–zirconium nitride powder mixtures with varying proportions were produced by changing the amount of boron nitride in the reactants. Products were subjected to powder X-ray diffraction analysis; and grain size and morphology was examined by scanning electron microscope. It was seen that the velocity of the wave front, adiabatic temperature of the reaction and grain size of the products decreased by increasing the boron nitride amount in the reactants. It was deduced from the scanning electron microscope examinations and crystal size calculations performed from the broadening of the peaks on the X-ray diffractions patterns that zirconium nitride grains were much finer than zirconium diboride grains.     

Comparative study of carbon nanotubes- and fullerenes-doped liquid crystal for different electrophoretic parameters

This research focuses on the study of different electrokinetic parameters of carbon nanotubes (CNTs) and fullerene aggregates in liquid crystal (LC) host medium, which are investigated in the homogeneously aligned nematic LC cells driven by in-plane field. The colloidal CNTs in LC medium are observed to move towards the negative electrodes whereas the fullerenes in LC medium are observed to move towards positive electrode at low frequencies. We propose a model to estimate the charge and zeta potential of colloidal particles by incorporating both the dielectrophoresis and electrophoresis forces in order to probe the reason of moving the colloidal particles in opposite direction. Interestingly, charge and zeta potential values on CNTs and fullerenes estimated from given model were positive and negative, respectively. The CNTs and fullerenes at high frequency and field are found to stretch along the direction of electric field. The CNTs dispersed whereas fullerenes start to move in perpendicular direction to the applied electric field with increasing electric field at high frequency.     

A New Molecular Mechanics Computer Program for Giant Fullerenes and Nanotubes

The molecular mechanics computer program is designed to study the structure of fullerenes with icosahedral symmetry and carbon nanotubes. The program takes full advantage of symmetry. The program predicts meaningful conformations, energies of formation for symmetrical fullerenes as well as for the carbon nanotubes for which also the elastic properties are calculated.

The systematic IUPAC nomenclature of fullerenes and fullerenes derivatives is discussed. Comments are made on terminology questions and on the chemical non-aromaticity of fullerenes.     

Transport properties in a mixed inorganic ion exchanger—zirconium phosphomolybdate—in comparison to its single salt counterparts

Amorphous inorganic ion exchangers zirconium phosphate, zirconium molybdate and zirconium phosphomolybdate have been prepared and characterized by elemental analysis, TGA, FTIR and surface area measurements. The protonic conductivity in these materials were determined at various temperatures and compared. It was found that the mixed material zirconium phosphomolybdate showed maximum conductivity at all temperatures.