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Reversible hydrogen adsorption in Ti-functionalized porous holey graphyne: Insights from first-principles calculation
Journal
Energy Storage
Date Issued
2023-02-01
Author(s)
Dewangan, Juhee
Mahamiya, Vikram
Shukla, Alok
Chakraborty, Brahmananda
Abstract
By performing the density functional theory simulations, we have studied the H2 adsorption and desorption properties of the Ti-functionalized holey graphyne system. The simulation results revealed that the Ti atom is bonded strongly to the holey graphyne sheet with a binding energy of −4.16 eV through the Dewar interaction. The Ti-functionalized holey graphyne can capture 7H2 molecules with an average H2 adsorption energy of −0.38 eV/H2, leading to a hydrogen gravimetric density of 10.52 wt%. The average desorption temperature is computed by the Van't Hoff relation and obtained to be 486 K, optimum for practical applications. The adsorbed H2 molecules are attached with the Ti-functionalized holey graphyne via the Kubas interactions involving charge donation and back donation between Ti-3d orbitals and H-1 s orbital. Subsequently, the ab initio molecular dynamics simulations have been conducted to verify the structural constancy of the storage media. We have found a sufficiently high energy barrier of 2.3 eV that prevents the system from metal-metal clustering. Therefore, the Ti-functionalized holey graphyne can be utilized as a promising high-capacity reversible hydrogen storage medium.
Volume
5
Subjects