A study of interaction potentials for H-2 adsorption in Single Walled Nano Tubes: a possible way to more realistic predictions

• Type: Article in International Scientific Journal
• Date: 2014

Authors

Marco Lerario (Author) Other; Alexandre L Magalhaes (Author) FCUP

Journal

Title: Journal Of Molecular Modeling

Vol. 20

ISSN: 1610-2940

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 1 Citation

Scopus - 1 Citation

Scientific classification

FOS: Natural sciences > Chemical sciences

Other information

Authenticus ID: P-009-M28

DOI: 10.1007/s00894-014-2194-8

Abstract (EN): A comparative analysis of interaction potentials, classified according to the parametrization method, namely Lorentz-Berthelot rules, semi-empirical or ab initio calculations, found their energy depths to scale, respectively, to ca30K, ca40K, and ca60K. We draw the Potential Energy Surfaces (PESs) for a hydrogen probe molecule inside a Carbon Nano-Tube (CNT): it is shown that the adsorption energy increases with the hard radius of the interaction potential and decreases as the CNT pore enlarges. This is valid just for low-medium pressures, when hydrogen repulsions are negligible. If not, adsorption is driven by H-2-H-2 hard radius despite all other parameters. Monte Carlo (MC) simulations, following the Gibbs Ensemble (GE) in high density conditions, confirm that the thermodynamic equilibrium of an order-disorder phase transition show no changes throughout any of the studied potentials. We also analyse, in the Grand Canonical (GC) ensemble, the geometric and structural characteristics of square lattice bundles of Single Walled Nano Tubes (SWNTs) with regard to their influence on adsorption storage. To do so, we develop a method for independently simulate inner or outer adsorption in infinitely long nanotube lattice systems. Our results suggest a pressure range for convenient H-2 storage and enlighten the influence of CNT size on adsorption performance. In addition, larger CNTs are capable to host further hydrogen layers, but only at very high pressures.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9