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Carbon Nanotubes for improving dehydrogenation from NaAlH4

Research paper by Meenakshi malhotra, Deepak Agnihotri, Hitesh Sharma

Indexed on: 15 Oct '16Published on: 14 Oct '16Published in: Computational and Theoretical Chemistry



Abstract

Carbon nanotubes (CNTs) improve the dehydrogenation kinetics of NaAlH4NaAlH4. The present paper reports the effect of small diameter CNTs for lowering the dehydrogenation energy from NaAlH4NaAlH4 cluster using Density functional theory. Pristine carbon nanotubes (P-CNTs) with Zig-Zag (n,0) and Armchair (n,n) chirality with n=3,4,5; chemically B/N doped CNTs (C-CNTs) and CNTs with vacancy defect (V-CNTs) are considered systematically to study the interaction with NaAlH4NaAlH4 cluster. NaAlH4NaAlH4 interacts with P-CNTs, C-CNTs and V-CNTs with binding energy of the order 0.77 eV-0.98 eV, 0.60 eV-1.01 eV and 0.81 eV-1.74 eV  respectively. The hydrogen release energy of NaAlH4NaAlH4 decreases from 3.95 eV   by 38%, 49% and 39% when interacting with P-CNTs, C-CNTs and V-CNTs respectively. Results can be explained on the basis of electronic charge transfer and redistribution between CNTs and NaAlH4NaAlH4 which weaken the bonds involved in cluster and enhance easy removal of hydrogen. The results are in agreement with the available experimental data.

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