Investigating detailed mechanism of hydrogen molecules adsorbing on single‐wall carbon nanotubes using fitted force field parameters containing carbon–carbon interactions. Issue 10 (11th October 2018)

• Record Type: Journal Article
• Authors: Kong, Chui‐Peng; Gao, Xin; Jia, Ran; Zhang, Hong‐Xing
• Other Names: Mo Yirong guestEditor.; Wu Wei guestEditor.; Cao Zexing guestEditor.
• Is Part Of: Journal of computational chemistry. Volume 40:Issue 10(2019)
• Page Start: 1073
• Page End: 1083
• Publication Date: 2018-10-11
• Subjects: SWNTs -- force field parameters -- hydrogen adsorption -- molecular dynamics study; Chemistry -- Data processing -- Periodicals; 542.85
• DOI: 10.1002/jcc.25593
• Languages: English
• ISSNs: 0192-8651

Abstract

Abstract : The nonbonded and bonded force field parameters for carbon atoms in single‐wall carbon nanotubes (SWNT) are fitted by means of quantum chemistry calculations with considering the periodic boundary conditions. The nonbonded parameters between carbon atoms and hydrogen atoms are fitted as well. All the fitted parameters are verified by comparing to quantum chemistry results and by calculating Young's modulus. Adsorption of Hydrogen molecules are then carried out on a bundle of self‐assembled SWNTs. The adsorption isotherms are consistent to the Freundlich equation. Both hydrogen molecules adsorbed outside and inside the SWNTs are counted. According to our result, hydrogen molecules adsorbed inside the SWNTs are more stable at a relatively high temperature and are playing an important part in total amount of the adsorbed molecules. While C(10, 10) have the highest adsorption capacities in most of the temperatures, hydrogen molecules inside C(5, 5) are the most stable of all the four kinds of SWNTs. Thus, balancing adsorption capacities and strength of interaction can be important in choosing SWNT for gas adsorption. Besides, we deduct an equation that can describe the relation between hydrogen pressure and amount of SWNTs based on our simulation results. The hydrogen pressure may decrease by adding SWNTs in the system. The fitting method in our system is valid to SWNTs and can be tested in further studies of similar systems. © 2018 Wiley Periodicals, Inc. Abstract : By fitting bonded and nonbonded force field parameters of carbon–carbon interaction and carbon–hydrogen interaction from QM calculations, hydrogen molecules adsorbed onto a bundle of self‐assembled SWNTs are elaborately simulated by means of molecular dynamics simulations. The adsorption results comply to the Freundlich isotherms. With the MD results, an equation is obtained to describe the decrease of hydrogen pressure in a system after adding certain amount of SWNTs.