Surface properties of fluorinated single-walled carbon nanotubes

Lee, Young Seak; Cho, Tae Hyun; Lee, Byoung Ky; Rho, Jae Seong; An, Kay Hyeok; Lee, Young Hee

doi:10.1016/s0022-1139(02)00316-0

Cited by 175 publications

(96 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Fluorine coverage of single walled CNTs increases with increasing temperature, reaching a maximum coverage of C 2 F between 250 and 300 C [14,15]. At higher temperatures the tubes break down into graphitic material where coverage can approach CF [16].…”

mentioning

confidence: 99%

“…X-ray photoelectron spectroscopy (XPS) studies show a change in C-F bonding type between 200 and 250 C. Up to 200 C the XPS spectra are centered at 688 eV (semi-ionic fluorination), whereas at 250 C the peak shifts to 691 eV (covalentlike fluorination) [14,15]. The change is reflected in the F=C ratio which jumps from 0.20-0.25 at 200 C to 0.5 at 250 C, while sample resistivity increases by a factor of 3 [15].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Pattern Formation on Carbon Nanotube Surfaces

et al. 2006

View full text Add to dashboard Cite

Calculations of fluorine binding and migration on carbon nanotube surfaces show that fluorine forms varying surface superlattices at increasing temperatures. The ordering transition is controlled by the surface migration barrier for fluorine atoms to pass through next neighbor sites on the nanotube, explaining the transition from semi-ionic low coverage to covalent high coverage fluorination observed experimentally for gas phase fluorination between 200 and 250 C. The effect of solvents on fluorine binding and surface diffusion is explored.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Pattern Formation on Carbon Nanotube Surfaces

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Determination of the structures of CNTs within the bundles, for example the helicity, can be obtained using TEM coupled with electron diffraction [12]. X-ray photoelectron spectroscopy (XPS) can be used to get information on the chemical structure of CNTs, for example to study the incorporation of nitrogen into carbon nanotubes [13], sidewall functionalization of SWNTs by fluorination [14]. Infrared spectroscopy is often used to determine impurities remaining from synthesis or molecules capped on the CNTs surface.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Carbon Nanofibers/ ZrO2 Ceramic Matrix Composite

Duszová¹,

Morgiel²,

Bastl³

et al. 2013

Archives of Metallurgy and Materials

View full text Add to dashboard Cite

Carbon micro/nanofibers prepared by catalytic chemical vapor deposition have been characterized in the form of powders and in the form of filaments, intercorporated in the matrix of ZrO 2 . Scanning electron microscopy, transmission electron microscopy, high resolution electron microscopy, electron spectroscopy for chemical analysis and Raman spectroscopy have been used. The outer diameter of the fibers varied from 50 nm to 600 nm with an average diameter of 120 nm, length from several micrometers to several tens of micrometers and inner diameters from 20 nm to 230 nm. Two types of fibers have been identified; cylindrical which consists of a distinct graphite layers parallel to the fiber axes and bamboo -shaped fibers with walls which are built from domains with different orientations of graphite layers. The fibers contain 99.05 at.% carbon and 0.95 at.% oxygen with a binding energy of O (1s) electrons of 532.7 eV which corresponds to carbon in C-O bonds. In the first-order Raman spectra, the position of the band G was found at 1600 cm −1 and D at 1282 cm −1 . The CNFs in ZrO 2 + CNFs composite have been relatively well dispersed, however clusters of CNFs together with porosity are present as a result of the difficulty of dispersing, too. TEM and HREM revealed that the CNFs are usually located at the grain boundaries of ZrO 2 in the form of undamaged nanofibers or disordered graphite.Keywords: Carbon nanofibers, Nanocomposites, Transmission electron microscopy, High resolution transmission electron microscopy, Raman spectroscopy Włókna węglowe przygotowane metodą osadzania z par (tzw. Chemical Vapour Deposition), były badane bezpośrednio po wytworzeniu oraz po wprowadzeniu do osnowy ceramicznej metodami elektronowej mikroskopii skaningowej, transmisyjnej oraz spektroskopii ramanowskiej. Średnica włókien wahała się pomiędzy 50 nm, a 600 nm przy średniej wartości ∼120 nm, podczas gdy ich długość wynosiła od kilku do kilkudziesieciu mikrometrów. Identyfikowano dwa rodzaje budowy włókien, tj. cylindryczne oraz z wewnętrznymi przekładkami typu "łodygi bambusa". Włókna węglowe zawierały do 0.95 at. % tlenu o energi wiązania O (1s) ∼532.7 eV, co odpowiada wiązaniu C-O. Na pierwszym widmie Ramana pasmo G identyfikowano dla 1600 cm −1 , a pasmo D dla 1282 cm −1 . Badania kompozytu wykazałay równomierny rozkład włókien w ceramicznej osnowie. W sąsiedztwie większych aglomeratów stwierdzono tendencje do występowania pustek. W czasie spiekania przeważająca część włókien zachowała swoją rurkową strukturę, natomiast pozostały materiał węglowy uległ przemianie do słabo uprządkowanych struktur grafitu lub nawet uległ amorfizacji.

show abstract

“…The latter group showed that fluorination alters conductivity of the SW-CNT from a good conductor to an insulator [248]. There has been ongoing studies on fluorination of carbon nanotubes [248,[252][253][254][255][256][257][258], while investigations of other types of carbon has been limited to a few studies on fullerene [259], activated carbon [241, [260][261][262][263] and graphene [249,264]. Most of these studies only focus on new synthesis methods of fluorinated carbons and just a very few of them have explored adsorption properties of these materials for gas adsorption and separation applications [241, [260][261][262][263].…”

Section: Heteroatom Doping Of Porous Materials For Gas Adsorption Andmentioning

confidence: 99%

Structural modelling of silicon carbide-derived microporous carbon and its application in CO2 capture and separation of volatile gases from moist streams

Farmahini¹

View full text Add to dashboard Cite

The adsorption of volatile gases in microporous materials has wide applications in gas separation, including CO 2 capture and natural gas dehydration. It has also attracted a large amount of attention for energy storage applications such as electrochemical energy storage in supercapacitors and adsorptive methane/hydrogen storage. Nevertheless, the development of efficient gas storage/separation technologies requires fundamental knowledge of fluid transport in narrow pore spaces, since the behavior of fluids under tight confinement differs markedly from that in the bulk.Along with the rapid development of a broad range of new microporous materials such as carbide derived carbons (CDCs), carbon nanotubes and metal-organic frameworks, there has been wide growth in their potential applications, especially in emerging nanotechnologies, thus the development of this understanding has become even more crucial.This study contributes to such understanding by investigating adsorption and transport of industrially important gases in the microporous structure of silicon carbide-derived carbon (SiC-DC). Initially, a realistic model of silicon carbide-derived carbon is developed using the hybrid reverse Monte Carlo (HRMC) method, which reliably represents the atomistic structure of the actual carbon sample and successfully predicts its gas adsorption and fluid transport properties.Following this part, structural characteristics of the constructed model are investigated using different computational methods to reveal the underlying correlations between such characteristics and the behavior of fluid transport in the highly disordered structure of SiC-DC. This study also explores adsorption and self-diffusion of fluid molecules in the amorphous SiC-CD model, providing more insight into the internal resistances and energy barriers to gas diffusion. The strong influence of structural heterogeneity arising from the disordered nature of the microporous carbon on molecular diffusion is also examined here using a range of computational techniques. The computational methods employed include molecular dynamics (MD) simulation, nudged elastic band (NEB) method and analysis of the free energy map of the system. It is shown that disordered structure of SiC-DC has larger energy barriers to diffusion of carbon dioxide, rather than methane despite smaller molecular size of CO 2 . It is also demonstrated that activation energy barriers for methane obtained from MD simulation are in remarkable agreement with that of macroscopic kinetic uptake at low loading, which is an indication of accuracy of the HRMC constructed model in capturing internal resistances and constrictions of the actual sample. However, quasi elastic neutron scattering (QENS) measurements suggests a smaller activation energy barrier for methane compared to the results obtained from MD simulations and macroscopic kinetic uptake experiments, which is due to the much smaller length scale in QENS compared to the macroscopic length scale. IIIDue to the significance of water a...

show abstract

Surface properties of fluorinated single-walled carbon nanotubes

Cited by 175 publications

References 10 publications

Pattern Formation on Carbon Nanotube Surfaces

Pattern Formation on Carbon Nanotube Surfaces

Characterization of Carbon Nanofibers/ ZrO2 Ceramic Matrix Composite

Structural modelling of silicon carbide-derived microporous carbon and its application in CO2 capture and separation of volatile gases from moist streams

Contact Info

Product

Resources

About