The adsorption properties of surface modified activated carbon fibers for hydrogen storages

Lee, Young Seak; Kim, Young Ho; Hong, Jin‐Yong; Suh, Jeong Kwon; Cho, Gyou Jin

doi:10.1016/j.cattod.2006.09.014

Cited by 67 publications

(32 citation statements)

References 25 publications

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“…Because fluorine gas has a strong reactivity, it can easily react with surface carbon, even at room temperature. Furthermore, the surface nature of activated carbons can be controlled, regardless of whether they are hydrophobic or hydrophilic, by direct fluorination and oxyfluorination [22].…”

Section: Surface Properties Of Oxyfluorinated Acfsmentioning

confidence: 99%

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage

Bai¹,

Kim²,

Im³

et al. 2011

Carbon letters

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The oxyfluorination effects of activated carbon nanofibers (OFACFs) were investigated for CO 2 storage. Electrospun CFs were prepared from a polyacrylonitrile/N,N-dimethylformamide solution via electrospinning and heat treatment. The electrospun CFs were chemically activated in order to generate the pore structure, and then oxyfluorination was used to modify the surface. The samples were labeled CF (electrospun CF), ACF (activated CF), OFACF-1 (O 2 :F 2 = 7:3), OFACF-2 (O 2 :F 2 = 5:5) and OFACF-3 (O 2 :F 2 = 3:7). The functional group of OFACFs was investigated using X-ray photoelectron spectroscopy analysis. The C-F bonds formed on surface of ACFs. The intensities of the C-O peaks increased after oxyfluorination and increased the oxygen content in the reaction gas. The specific surface area, pore volume and pore size of OFACFs were calculated by the Brunauer-Emmett-Teller and density functional theory equation. Through the N 2 adsorption isotherm, the specific surface area and pore volume slightly decreased as a result of oxyfluorination treatment. Nevertheless, the CO 2 adsorption efficiency of oxyfluorinated ACF improved around 16 wt% due to the semi-ionic interaction effect of surface modificated oxygen functional groups and CO 2 molecules.

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Section: Surface Properties Of Oxyfluorinated Acfsmentioning

confidence: 99%

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage

Bai¹,

Kim²,

Im³

et al. 2011

Carbon letters

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“…The advantages of ACFs compared with conventional activated carbons are smaller fiber diameter, a narrower pore size distribution and excellent adsorption capacity at low concentration of adsorbates [9,10]. Therefore, ACFs are promising electrode materials for high sensitivity of gas sensors.…”

Section: Introductionmentioning

confidence: 99%

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Kang¹,

Sun²,

Lee

2011

Carbon letters

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A novel electrode for an NO gas sensor was fabricated from electrospun polyacrylonitrile fibers by thermal treatment to obtain carbon fibers followed by chemical activation to enhance the activity of gas adsorption sites. The activation process improved the porous structure, increasing the specific surface area and allowing for efficient gas adsorption. The gas sensing ability and response time were improved by the increased surface area and micropore fraction. High performance gas sensing was then demonstrated by following a proposed mechanism based on the activation effects. Initially, the pore structure developed by activation significantly increased the amount of adsorbed gas, as shown by the high sensitivity of the gas sensor. Additionally, the increased micropore fraction enabled a rapid sensor response time due to improve the adsorption speed. Overall, the sensitivity for NO gas was improved approximately six-fold, and the response time was reduced by approximately 83% due to the effects of chemical activation.

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“…al. [194], and Li et al [195,196] have shown that fluorination of activated carbon fibre (ACF) reduces N 2 adsorption and ethanol adsorption due to reduction in surface area, pore size, pore volume, and the surface energy [193,194]. They demonstrate the level of fluorination to have an inverse relation with pore volume, surface area and mean pore width of the surface modified activate carbon fibers.…”

Section: Functionalization and Surface Modification Of Carbon Materialsmentioning

confidence: 99%

Adsorption analysis of carbon dioxide, hydrocarbons and moisture on carbon

Abadi¹

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This thesis presents a fundamental investigation on the role of the structure of microporous silicon carbide-derived carbon (SiCDC) and its functionalisation in the adsorption equilibria and transport of gases. The SiCDCs with different particle size distributions were synthesized in our laboratory and characterized using a combination of techniques including scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Xray diffraction (XRD), helium pycnometry, thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Raman spectroscopy, and gas adsorption.Based on the characterisation results, a bidisperse pore structure model is proposed for the synthesized SiCDC to explain the kinetics. In the mathematical modelling of adsorption kinetics, the internal structure of SiCDC is assumed to have ultra-microporous grains with larger particle scale micropores forming the intergrain pathways. It is shown that CH 4 adsorption kinetics is governed by two distinct diffusional resistances, arising from slow grain scale diffusion in ultra-micropores and faster particle scale diffusion in large micropores. For CO 2 , it is found that the adsorption kinetics is strongly influenced by a barrier resistance at the grain surface where entry into the ultra-microporosity occurs. The uptake of CO 2 in the bidisperse pore structure of CDCs occurs through rapid diffusion in the large particle-scale micropores, in which a Henry law isotherm holds, and a combination of barrier resistance at the grain surface and diffusional resistance in the grain interior with a Langmuirian isotherm. It is shown that the grain scale activation energies are comparable with values for carbon molecular sieves, and consistent with values expected for the size range of the ultra-micropores, while the activation energies for transport in the larger particle scale micropores are comparable to those for conventional activated carbons.The experimental uptake-based data are compared with self-diffusivities obtained through equilibrium molecular dynamics (EMD) simulations using a realistic model of SiCDC developed by the hybrid reverse Monte Carlo (HRMC) method. It is observed that MD-based CO 2 diffusivities are as much as two orders of magnitude larger than the CO 2 particle scale diffusion coefficients, however such discrepancy is not found for The findings of this thesis should aid better understanding of the gas adsorption and diffusion mechanism in microporous CDCs.iv

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The adsorption properties of surface modified activated carbon fibers for hydrogen storages

Cited by 67 publications

References 25 publications

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Adsorption analysis of carbon dioxide, hydrocarbons and moisture on carbon

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The adsorption properties of surface modified activated carbon fibers for hydrogen storages

Cited by 67 publications

References 25 publications

Influence of oxyfluorination on activated carbon nanofibers for CO2storage

Influence of oxyfluorination on activated carbon nanofibers for CO2storage

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Adsorption analysis of carbon dioxide, hydrocarbons and moisture on carbon

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Product

Resources

About

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage

Influence of oxyfluorination on activated carbon nanofibers for CO₂storage