Pulling Simulations and Hydrogen Sorption Modelling on Carbon Nanotube Bundles

Abstract

Recent progress in molecular simulation technology has developed an interest in modernizing the usual computational methods and approaches. For instance, most of the theoretical work on hydrogen adsorption on carbon nanotubes was conducted a decade ago. It should be insightful to reinvestigate the field and take advantage of code improvements and features implemented in contemporary software. One example of such features is the pulling simulation modules now available in many molecular dynamics programs. We conduct pulling simulations on pairs of carbon nanotubes and measure the inter-tube distance before they dissociate in water. We use this distance to set the interval size between adjacent nanotubes as we arrange them in bundle configurations. We consider bundles with triangular, intermediate and honeycomb patterns, and armchair nanotubes with a chiral index from n = 5 to n = 10. Then, we simulate low pressure hydrogen adsorption isotherms at 77 K, using the grand canonical Monte Carlo method. The different bundle configurations adsorb great hydrogen amounts that may exceed 2% wt at ambient pressures. The computed hydrogen capacities are considered large for physisorption on carbon nanostructures and attributed to the ultra-microporous network and extraordinary high surface area of the configured models.

Binding Free Energy Calculations of Bilayer Graphenes Using Molecular Dynamics

“…Using these structures, we configured three bilayer graphenes with small, medium, and large sizes, respectively. We modeled the sp 2 carbon atoms on the basis of the OPLSAA references of naphthalene and of aliphatic carbons. − We modeled the hydrogen atoms using the interaction parameters of benzene hydrogens. The structures were uncharged.…”

On the Consistency of the Exfoliation Free Energy of Graphenes by Molecular Simulations

“…We placed the copied layers in a parallel orientation, at a distance 0.3 nm from each other. We modeled the carbon atoms on the basis of the OPLSAA references of naphthalene and of aliphatic carbons [ 48 , 49 , 50 , 51 ]. We modeled hydrogen interactions using the interaction parameters of benzene hydrogens.…”

Umbrella Sampling Simulations of Carbon Nanoparticles Crossing Immiscible Solvents

“…Many of the pioneering simulations of surface phenomena involve studies of gases and liquids interacting with carbon solids [1][2][3][4]. Gas-solid or liquid-solid adsorption simulations allow assessing information about the micropore size, the surface area, and some aspects of the surface chemistry of sorbent materials [5][6][7][8]. Porous texture characterization based on gas adsorption is associated with a number of classical and advanced simulation tools performing at the microscopic level such as the density functional theory and Monte Carlo simulations [9][10][11].…”