Coordination of nickel atoms with Al12X12 (X = N, P) nanocages enhances H2 adsorption: A surface study by DFT. (November 2016)

• Record Type: Journal Article
• Authors: Rad, Ali Shokuhi; Ayub, Khurshid
• Is Part Of: Vacuum. Volume 133(2016)
• Page Start: 70
• Page End: 80
• Publication Date: 2016-11
• Subjects: Hydrogen adsorption -- Al12N12 -- Al12P12 -- Nickel -- Nanostructure adsorbent; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2016.08.017
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Density functional theory (DFT) calculations have been performed to study the adsorption of hydrogen on the surface of pristine and nickel decorated Al12 N12 and Al12 P12 nano-cages. Decoration of nickel on the surface of nano-cages delivers four distinct geometries. Hydrogen adsorption is studied on the surface of Ni-decorated Al12 X12 (X = N, P) in these four geometries (named as P1, P2, P3, and P4). Calculations reveal very weak physisorption of H2 on pristine nano-cages while significant enhancement in its adsorption properties is found upon using Ni-X12 Y12 nano-cages. The hydrogen adsorption on Ni-Al12 N12 nano-cage is in order of P2 > P3 > P4 > P1, whereas the order of adsorption energies on Ni-Al12 P12 is P2 > P1 > P3 > P4. Ni complexation with Al12 N12 shows considerably higher potential for H2 adsorption compared to Al12 P12 . We used natural bond orbital (NBO), molecular dipole moment, density of states (DOS) and frontier molecular orbitals analyses to observe the changes in the electronic structure of Ni-Al12 X12 nano-cages on adsorption of H2 . Highlights: Decoration of nickel on Al12 X12 (X = N, P) nano-cages provides four distinct geometries. H2 adsorption on pristine Al12 X12 (X = N, P) nano-cages is really low. Decorated nickel at Ni-Al12 X12 (X = N, P) nano-cages increases H2 adsorption significantly. Adsorbed nickel changes HOMO and LUMO distributions of Al12 X12 (X = N, P), drastically.