Reversible hydrogen adsorption in Ti‐functionalized porous holey graphyne: Insights from first‐principles calculation
Juhee Dewangan, Vikram Mahamiya, Alok Shukla, Brahmananda Chakraborty
Abstract
Abstract By performing the density functional theory simulations, we have studied the H 2 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 7H 2 molecules with an average H 2 adsorption energy of −0.38 eV/H 2 , 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 H 2 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.