Carbon dioxide sequestration by carbon nanotubes: Application of graph theoretical approach

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• 作者：Deniz Rende ; Nihat Baysal ; Rahmi Ozisik
• 关键词：Molecular dynamics ; CO₂ sequestration ; Carbon nanotubes ; Graph theory ; Interaction networks
• 刊名：Computational Materials Science
• 出版年：2010
• 出版时间：April 2010
• 年：2010
• 卷：48
• 期：2
• 页码：402-408
• 全文大小：1996 K

文摘

A graph theoretical approach is applied to analyze the dynamic evolution of retention of carbon dioxide (CO₂) molecules in single-walled carbon nanotubes (SWNTs). The trajectories of the molecules were obtained from the Molecular Dynamics (MD) simulations performed at constant temperature, T = 300 K, with a duration of 10 ns. The simulation box contains four single-walled carbon nanotubes and 408 CO₂ molecules with a bulk number density of 0.042 nm⁻³. Non-bonding interaction distances between CO₂ molecules during the simulation were calculated in 1 ns intervals and these values were used to construct 10 dynamic interaction networks, by taking a cut-off value of 0.9 nm for the van der Waals distance. Each of these interaction networks were then analyzed with the two global measures of graph theory: connectivity and clustering coefficient. Our results signified that an increase in the average clustering coefficient in corresponding networks is a reliable indicator for CO₂ sequestration in single-walled carbon nanotubes. In addition, the distance distribution for each of the interaction networks revealed that the CO₂ molecules retained in carbon nanotubes have a tendency to localize around a distance of 0.48 nm. Consequently, the network representation of CO₂ molecules and their encapsulation in SWNTs is in agreement with the actual MD simulation. In summary, the study presented here uses graph theoretical approach to interpret the results received from MD simulations providing a powerful tool to analyze such simulations.