Investigation of unified impact of Ti adatom and N doping on hydrogen gas adsorption capabilities of defected graphene sheets

Luhadiya, N and Choyal, V and Kundalwal, SI and Sahu, SK (2023) Investigation of unified impact of Ti adatom and N doping on hydrogen gas adsorption capabilities of defected graphene sheets. In: Journal of Molecular Graphics and Modelling, 119 .

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Abstract

In this work, we studied the hydrogen adsorption capabilities of functionalized graphene sheets containing a variety of defects (D-G) via molecular dynamics (MD) simulations that govern the mechanisms involved in hydrogen adsorption. Specifically, the graphene sheets containing monovacancy (MV), Stone-Wales (SW), and multiple double vacancy (DV) defects were functionalized with Ti and N atoms to enhance their hydrogen adsorption capacity. We measured the adsorption capacities of the N-/D-G sheets with varying concentrations of Ti adatoms at 300 K and 77 K temperatures and various pressures. Our study revealed that the increasing concentration of Ti adatoms on the D-G sheets led to a significant improvement in the hydrogen adsorption capacity of the graphene sheets. The DV(III)-G sheets showed the maximum adsorption capacity at 300 K because the DV(III)-G sheets had a small number of large-sized pores that bind hydrogen with high binding energy. Thus, hydrogen remained adsorbed even at higher temperatures (300 K). The N doping on the D-G sheets initially reduced their hydrogen adsorption capabilities; however, the N-D-G sheets enhanced their hydrogen adsorption capacity with the increasing concentrations of Ti adatoms. Compared to all other defect types, the Ti–N-DV(III)-G sheet with a Ti concentration of 10.5% showed a hydrogen uptake of 5.5 wt% at 300 K and 100 bar pressure. Thus, the N doping and Ti implantations improved the hydrogen storage capabilities of the graphene sheets, and these findings helped design solid-state hydrogen storage systems operating at ambient conditions and moderate pressure ranges.

Item Type:	Journal Article
Publication:	Journal of Molecular Graphics and Modelling
Publisher:	Elsevier Inc.
Additional Information:	The copyright for this article belongs to Elsevier Inc.
Keywords:	Adatoms; Binding energy; Defects; Gas adsorption; Graphene; Hydrogen storage; Nitrogen; Titanium, Adsorption capability; Adsorption capacities; Graphene defects; Graphene sheets; Hydrogen adsorption; Hydrogen adsorption capacity; N-Doping; Nitrogen-doping; Titania; Titania adatom, Molecular dynamics
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	27 Jan 2023 07:12
Last Modified:	27 Jan 2023 07:12
URI:	https://eprints.iisc.ac.in/id/eprint/79528

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