共查询到20条相似文献,搜索用时 15 毫秒
1.
Tayfun Vural 《Applied Surface Science》2010,257(2):622-627
In this work, preparation and characterization of single-walled carbon nanotube-chitosan (SWNT-chitosan) modified disposable pencil graphite electrode (PGE) was carried out. Firstly, commercial single-walled carbon nanotube was purified and characterized using thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy dispersive analysis of X-ray (EDX) for this purpose. Purified SWNT was mixed with chitosan polymer for preparing their composite. Then, PGE was modified with this composite. The characterization of the modified electrode was carried out using atomic force microscopy (AFM). The electrochemical behaviour of the obtained electrode was investigated and compared with the electrochemical behaviour of chitosan modified and unmodified PGEs using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and alternative current (AC) impedance spectroscopy. In order to obtain more sensitive electrochemical signals, the effect of SWNT concentration was studied. This modified electrode also showed electrocatalytic effect for hydrogen evolution. 相似文献
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Electric field aligned, single-walled carbon nanotubes are grown between electrodes using thermal chemical vapour deposition (CVD) of methane. The growth occurs on a thin film layered catalyst of aluminium, iron and molybdenum patterned on top of electrodes. The nanotubes bridge 10 μm sized electrode gaps and have a typical diameter of less than 2 nm as measured by Raman spectroscopy and atomic force microscopy. We present electrical transport measurements on a directly grown nanotube which shows p-type semiconducting behaviour. 相似文献
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Leyong Zeng Da Lei Weibiao Wang Jingqiu Liang Ning Yao 《Applied Surface Science》2008,254(6):1700-1704
Carbon nanosheets were synthesized by microwave plasma-enhanced chemical vapor deposition method on carbon nanotubes substrate which was treated by hydrogen plasma. The results showed that the diameters of carbon nanotubes first got thick and then “petal-like” carbon nanosheets were grown on the outer wall of carbon nanotubes. The diameters of carbon nanotubes without and with carbon nanosheets were 100-150 and 300-500 nm, respectively. Raman spectrum indicated the graphite structure of carbon nanotubes/carbon nanosheets. The hydrogen plasma treatment and reaction time greatly affected the growth and density of carbon nanosheets. Based on above results, carbon nanosheets/carbon nanotubes probably have important applications as cold cathode materials and electrode materials. 相似文献
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An electrochemical impedance immunosensor was developed for detecting the immunological interaction between human immunoglobulin
(IgG) and protein A from Staphylococcus aureus based on the immobilization of human IgG on the surface of modified gold-coated magnetic nanoparticles. The nanoparticles
with an Au shell and Fe oxide cores were functionalized by a self-assembled monolayer of 11-mercaptoundecanoic acid. The electrochemical
analysis was conducted on the modified magnetic carbon paste electrodes with the nanoparticles. The magnetic nanoparticles
were attached to the surface of the magnetic carbon paste electrodes via magnetic force. The cyclic voltammetry technique
and electrochemical impedance spectroscopy measurements of the magnetic carbon paste electrodes coated with magnetic nanoparticles–human
IgG complex showed changes in its alternating current (AC) response both after the modification of the surface of the electrode
and the addition of protein A. The immunological interaction between human IgG on the surface of the modified magnetic carbon
paste electrodes and protein A in the solution could be successfully monitored. 相似文献
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The regular adsorption of fluorine atoms on the surfaces of single-walled carbon nanotubes along their cylindrical axes leads to a modification of cylindrical carbon skeletons of these single-walled carbon nanotubes into carbon skeletons that have a nearly “anti-prismatic” shape (anti-prismatic modifications). In the faces of these modified single-walled carbon nanotubes, there can arise quasi-one-dimensional isolated carbon conjugated subsystems (tracks) with different structures. Model fragments of nanotubes of the (n, 0) type that contain up to 360 carbon atoms and their derivatives with regularly adsorbed fluorine atoms on the graphene surface have been calculated using the semiempirical PM3 method. It has been found that the main properties of the single-walled carbon nanotubes modified by the above method are determined by the character of the conjugation of the electrons in isolated carbon tracks, which is close to the character of the conjugation of the electrons in the initial single-walled carbon nanotubes. 相似文献
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We report on the interaction of hydrogen with sp2-bonded carbon which has been investigated on graphite (0001), single-walled carbon nanotubes and C60 multilayer films. These substrates have been chosen to represent a large range of curvature in the carbon network. The photoelectron spectroscopy study of the samples treated with atomic hydrogen and low-energy hydrogen ions reveals that hydrogen is chemisorbed on the basal plane of the sp2-bonded carbon networks, as evidenced by the lowered emission from -derived states and a lowering of the electron work function of up to 1.3 eV. The hydrogen adsorption energy barrier is found to strongly depend on the local curvature of the carbon network whereby the barrier is lowered with increasing curvatures. Whereas in the case of C60 and single-walled carbon nanotubes, hydrogen chemisorption can be achieved by exposure to atomic hydrogen, the chemisorption on graphite (0001) requires hydrogen ions of low kinetic energy (1 eV). Furthermore, the adsorption energy barrier is found to increase with hydrogen coverage.The scanning tunnelling microscopy study of individual adsorption sites on the graphite (0001) surface reveals long-ranged (5 nm) electronic effects observed as a (sqrt(3)×sqrt(3))R30° superstructure in the local density of states. It is shown that this superstructure is due to the scattering of delocalized electron wavefunctions at the point defects. The resulting standing waves induce a redistribution of the local density of states which is directly related to the point-like Fermi surface of graphite. PACS 68.43.-h; 71.20.Tx; 68.37.Ef 相似文献
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R. Krupke F. Hennrich H.B. Weber D. Beckmann O. Hampe S. Malik M.M. Kappes H. v. Löhneysen 《Applied Physics A: Materials Science & Processing》2003,76(3):397-400
Single bundles of carbon nanotubes have been selectively deposited from suspensions onto sub-micron electrodes with alternating
electric fields. We show that it is possible to control the trapping of a single bundle by the use of Ag as electrode material
which, unlike Au, strongly interacts with the carboxyl functionalized carbon nanotubes. Excellent alignment of the bundles
between Au or Ag electrodes occurs at frequencies above 1 kHz, with superior contacts being formed with Ag electrodes.
Received: 22 May 2002 / Accepted: 21 June 2002 / Published online: 28 October 2002
RID="*"
ID="*"Corresponding author. Fax: +49-7247/82-6368, E-mail: ralph.krupke@int.fzk.de 相似文献
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Adsorption on single walled carbon nanotubes (SWCNTs) is a subject of growing experimental and theoretical interest. The possible
adsorbed patterns of atoms and molecules on the single-walled carbon nanotubes vary with the diameters and chirality of the
tubes due to the confinement. The curvature of the carbon nanotube surface enlarges the distance of the adsorbate atoms and
thus enhances the stability of high coverage structures of adsorbate. There exist two novel high-coverage stable structures
of potassium adsorbed on SWCNTs, which are not stable on graphite. The electronic properties of SWCNTs can be modified by
adsorbate atoms and metal-semiconductor and semiconductor-semi-conductor transitions can be achieved by the doping of alkali
atoms. 相似文献
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A. V. Bazhenov T. N. Fursova I. O. Bashkin I. V. Kondrat’eva A. V. Krestinin Yu. M. Shul’ga 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(2):245-248
Single-walled carbon nanotubes containing 5.4 wt% H are prepared under a hydrogen pressure of 50 kbar at the temperature T = 500°C. Analysis of the optical transmission spectra has revealed that the hydrogenation of single-walled carbon nanotubes brings about suppression of high-frequency conduction provided by free charge carriers in the nanotubes, the disappearance of interband electronic transitions, and the appearance of an absorption line at 2845 cm?1 corresponding to stretching vibrations of the C-H bonds. The removal of hydrogen from hydrogenated single-walled carbon nanotubes owing to vacuum annealing at a temperature of 500°C is accompanied by a linear decrease in the intensity of this line as the hydrogen content in the system decreases. This phenomenon indicates that the greater part of the hydrogen atoms in single-walled carbon nanotubes are covalently bonded to the carbon atoms. 相似文献
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O. B. Tomilin I. V. Stankevich E. E. Muryumin S. A. Lesin N. P. Syrkina 《Physics of the Solid State》2011,53(1):201-208
The regular adsorption of fluorine atoms on surfaces of single-walled carbon nanotubes along their axes can lead to a modification
of cylindrical carbon cores of these single-walled carbon nanotubes to carbon cores that have a nearly prismatic shape (prismatic
modification). In faces of these modified single-walled carbon nanotubes, there can arise quasi-one-dimensional isolated carbon
conjugated subsystems (tracks) with different structures. It has been established that the main characteristics of the single-walled
carbon nanotubes thus modified are rather close to the corresponding characteristics of the related isostructural polymer
conjugated systems (such as cis-polyenes, polyphenylenes, poly(periacenes), or polyphenantrenes). Fragments of model nanotubes of the (n, n) and (n, 0) types that contain up to 360 carbon atoms and their derivatives doped with fluorine atoms have been calculated using
the semiempirical parametric method 3. 相似文献
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Flexible polyethylene terephthalate (PET) electrodes based on pristine single-walled carbon nanotubes (SWCNTs) and acid-treated single-walled carbon nanotubes (A-SWCNTs) were prepared by spray coating technique. Flexible A-SWCNTs electrodes showed enhanced electrochemical properties compared to the pristine SWCNTs electrodes. The electrochemical properties of the flexible A-SWCNTs electrodes were optimized with various types of aqueous electrolytes including sulfuric acid (H2SO4), sodium sulfate (Na2SO4), potassium chloride (KCl), sodium hydroxide (NaOH), and potassium hydroxide (KOH). The electrochemical performance of the A-SWCNTs electrodes as a function of bending to 30° were evaluated using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge (GCD) measurements in 1 M H2SO4. The specific capacitance value of the unbent A-SWCNTs electrode was 67 F g?1, which decreased to 63 F g?1 (94% retention) after 1000 GCD cycles. Interestingly, the specific capacitance of the unbent A-SWCNTs electrode with application of the 1000 GCD cycles was retained even after 500 bending to 30° with 6000 GCD cycles. 相似文献
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M. M. Brzhezinskaya E. M. Baitinger E. A. Belenkov L. M. Svirskaya 《Physics of the Solid State》2013,55(4):850-854
Experimental results of studying the electronic structure of single-walled and multi-walled carbon nanotubes as well as graphite by X-ray absorption spectroscopy (or NEXAFS spectroscopy) are presented. The C1s absorption spectra are measured with high energy resolution using the equipment of the Russian-German beamline of the BESSY electron storage ring. Features found in absorption spectra of carbon nanotubes and graphite for the first time are interpreted in the case of carbon nanotubes as the contribution of electron states appearing due to the imperfection of their structure both under the nonequilibrium synthesis conditions and during the subsequent producing manipulations. 相似文献
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M. M. Brzhezinskaya A. S. Vinogradov A. V. Krestinin G. I. Zvereva A. P. Kharitonov I. I. Kulakova 《Physics of the Solid State》2010,52(4):876-883
The C 1s and F 1s X-ray absorption spectra of pristine and fluorinated single-walled carbon nanotubes with different fluorine contents and
nanodiamond as a reference compound have been measured with the aim of characterizing single-walled carbon nanotubes and their
products formed upon treatment of the nanotubes with molecular fluorine at a temperature of 190°C. The spectra obtained have
been analyzed by thoroughly comparing with the previously measured spectra of highly oriented pyrolytic graphite and fluorinated
multiwalled carbon nanotubes and the spectrum of nanodiamond. It has been established that the fluorination of single-walled
and multiwalled carbon nanotubes leads to similar results and is characterized by the attachment of fluorine atoms to carbon
atoms on the lateral surface of the nanotube with the formation of the σ(C-F) bonds due to the covalent mixing of F 2p and C 2p
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π valence electron states. 相似文献
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A. V. Pak N. G. Lebedev 《Russian Journal of Physical Chemistry B, Focus on Physics》2012,6(2):321-326
A model of the multiple adsorption of atomic hydrogen on the surface of single-walled carbon nanotubes of the zigzag and arm-chair types was constructed. The adsorption model is based on the Anderson periodic model. An analytic equation for the band structure of carbon nanotubes with adsorbed hydrogen atoms was obtained, and the special features of this structure were studied. The dependence of the band structure of carbon nanotubes on the concentration of adsorbed hydrogen atoms was analyzed. The model constructed can be used to study adsorption of other univalent atoms on the surface of carbon particles. 相似文献
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Jianlei Cui Xiaoqiao He Xuesong Mei Wenjun Wang Xinju Yang Hui Xie Lijun Yang Yang Wang 《Journal of nanoparticle research》2017,19(3):110
Carbon nanotubes (CNTs), including single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs), are considered to be the promising candidates for next-generation interconnects with excellent physical and chemical properties ranging from ultrahigh mechanical strength, to electrical properties, to thermal conductivity, to optical properties, etc. To further study the interfacial contact configurations of SWNT-based nanodevice with a 13.56-Å diameter, the corresponding simulations are carried out with the molecular dynamic method. The nanotube collapses dramatically into the surface with the complete collapse on the Au/Ag/graphite electrode surface and slight distortion on the Si/SiO2 substrate surface, respectively. The related dominant mechanism is studied and explained. Meanwhile, the interfacial contact configuration and behavior, depended on other factors, are also analyzed in this article. 相似文献
20.
The electrochemical and electrocatalytic behavior of glassy carbon electrodes modified by one mono and four dihydroxy derivatives of anthra-9,10-quinone compounds have been investigated by cyclic voltammetric technique. The stability of the modified electrodes was ascertained in acidic and neutral media. The surface morphology of modified electrode was characterized by scanning electron microscope. The influence of pH on the electrochemical and electrocatalytic behavior was studied and pH?6.0 or 7.0 was chosen as the optimum working pH by comparing the shift in oxygen reduction potential. The anthraquinone-adsorbed glassy carbon electrodes possess excellent electrocatalytic ability for oxygen reduction with overpotential ranging from 388 to 547?mV lower than that at a plain glassy carbon electrode. Hydrodynamic volatammetric studies were performed to determine the heterogeneous rate constants for the reduction of O2 at the surface of the modified electrodes, mass specific activity of the anthraquinones used, and the apparent diffusion coefficient of O2 in buffered aqueous O2-saturated solutions. 相似文献