Influence of structural heterogeneity on diffusion of CH4 and CO2 in silicon carbide-derived nanoporous carbon

Farmahini, Amir H., Shahtalebi, Ali, Jobic, Herve and Bhatia, Suresh K. (2014) Influence of structural heterogeneity on diffusion of CH4 and CO2 in silicon carbide-derived nanoporous carbon. Journal of Physical Chemistry C, 118 22: 11784-11798. doi:10.1021/jp502929k


Author Farmahini, Amir H.
Shahtalebi, Ali
Jobic, Herve
Bhatia, Suresh K.
Title Influence of structural heterogeneity on diffusion of CH4 and CO2 in silicon carbide-derived nanoporous carbon
Formatted title
Influence of structural heterogeneity on diffusion of CH4 and CO2 in silicon carbide-derived nanoporous carbon
Journal name Journal of Physical Chemistry C   Check publisher's open access policy
ISSN 1932-7455
1932-7447
Publication date 2014-06-05
Year available 2014
Sub-type Article (original research)
DOI 10.1021/jp502929k
Open Access Status
Volume 118
Issue 22
Start page 11784
End page 11798
Total pages 15
Place of publication Washington DC, United States
Publisher American Chemical Society
Collection year 2015
Language eng
Formatted abstract
We investigate the influence of structural heterogeneity on the transport properties of simple gases in a Hybrid Reverse Monte Carlo (HRMC) constructed model of silicon carbide-derived carbon (SiC-DC). The energy landscape of the system is determined based on free energy analysis of the atomistic model. The overall energy barriers of the system for different gases are computed along with important properties, such as Henry constant and differential enthalpy of adsorption at infinite dilution, and indicate hydrophobicity of the SiC-DC structure and its affinity for CO2 and CH4 adsorption. We also study the effect of molecular geometry, pore structure and energy heterogeneity considering different hopping scenarios for diffusion of CO2 and CH4 through ultramicropores using the Nudged Elastic Band (NEB) method. It is shown that the energy barrier of a hopping molecule is very sensitive to the shape of the pore entry. We provide evidence for the influence of structural heterogeneity on self-diffusivity of methane and carbon dioxide using molecular dynamics simulation, based on a maximum in the variation of self-diffusivity with loading. A comparison of the MD simulation results with self-diffusivities from quasi-elastic neutron scattering (QENS) measurements and, with macroscopic uptake-based low-density transport coefficients, reveals the existence of internal barriers not captured in MD simulation and QENS experiments. Nevertheless, the simulation and macroscopic uptake-based diffusion coefficients agree within a factor of 2-3, indicating that our HRMC model structure captures most of the important energy barriers affecting the transport of CH4 in the nanostructure of SiC-DC.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2015 Collection
 
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Citation counts: TR Web of Science Citation Count  Cited 12 times in Thomson Reuters Web of Science Article | Citations
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