Hydrogen adsorption capacities of multi-walled boron nitride nanotubes and nanotube arrays: a grand canonical Monte Carlo study

Abstract

Hydrogen adsorption in multi-walled boron nitride nanotubes and their arrays was studied using grand canonical Monte Carlo simulation. The results show that hydrogen storage increases with tube diameter and the distance between the tubes in multi-walled boron nitride nanotube arrays. Also, triple-walled boron nitride nanotubes present the lowest level of hydrogen physisorption, double-walled boron nitride nanotubes adsorb hydrogen better when the diameter of the inner tube diameter is sufficiently large, and single-walled boron nitride nanotubes adsorb hydrogen well when the tube diameter is small enough. Boron nitride nanotube arrays adsorb hydrogen, but the percentage of adsorbed hydrogen (by weight) in boron nitride nanotube arrays is rather similar to that found in multi-walled boron nitride nanotubes. Also, when the Langmuir and Langmuir-Freundlich equations were fitted to the simulated data, it was found that multi-layer adsorptivity occurs more prominently as the number of walls and the tube diameter increase. However, in single-walled boron nitride nanotubes with a small diameter, the dominant mechanism is monolayer adsorptivity.

Investigations of CO2, CH4 and N2 physisorption in single-walled silicon carbon nanotubes using GCMC simulation

“…These observations emphasize that the LangmuirFreundlich is the best fitting that illustrates the adsorption of gases imply with varying energetic inhomogeneity in both (10,10) as smaller diameter and (40,40) as larger diameter SWSiCNTs [14,15]. However, the gases adsorption adaptation to the Langmuir-Freundlich model can distinguish that multi-layer adsorptivity is very feasible [14,15]. Because the pressure is increased and temperature is lowered, additional layers are formed.…”

“…The periodic boundary condition (PBC) is imposed in tube length direction. Further GCMC details are available in our previous publications [14,15].…”

“…Following our previous work [14,15], the GCMC simulation was adopted here for SWSiCNTs with (10,10), (20,20) and (40,40) chirality and 50 nm tube length with 17.857, 35.714 and 71.429 Å diameters, respectively, in order to consider CH 4 , N 2 and CO 2 physisorption from 294 to 343 K and 1 to 21,000 kPa range of temperature and pressure, respectively. The Si-C bond length is 1.87 Å [16].…”

Hydrogen physisorption and selectivity in single-walled silicon carbon nanotubes: a grand canonical Monte-Carlo study

“…In small diameters, especially in nanotubes with diameters less than 20 Å, the repulsion contribution of interactions between wall's atoms of nanotubes and guest molecules is considerable that it reduces the possibility of remaining of the hydrogen molecules inside the nanotube, according to the logic of the GCMC procedure [28,29]. Hence, the capacities of small nanotubes for adsorption of hydrogen decrease and low loading has taken place in this situation.…”

A quantum chemistry study of curvature effects on boron nitride nanotubes/nanosheets for gas adsorption

“…12 The adsorption properties have been systematically studied both experimentally and theoretically using quantum mechanics and molecular simulation methods. Many gas molecules, including H 2 , [13][14][15] N 2 , 16,17 methane, 18,19 noble gases, 20 and others as well as their mixtures, have been successfully investigated. Defects and packing effects on carbon surfaces were also studied.…”