Table of Contents Author Guidelines Submit a Manuscript
Journal of Nanotechnology
Volume 2012, Article ID 831872, 9 pages
http://dx.doi.org/10.1155/2012/831872
Research Article

Titanium as a Potential Addition for High-Capacity Hydrogen Storage Medium

1Theoretische Chemie, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands
2Tata Steel Research, Development and Technology, Tata Steel Europe, 1970 CA Ijmuidem, The Netherlands
3Science and Technology Facilities Council Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
4WCU Program, Department of Chemistry, Pohang University of Science and Technology, Pohang, Republic of Korea
5Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia

Received 7 March 2012; Accepted 1 May 2012

Academic Editor: Won Baek Kim

Copyright © 2012 Filippo Zuliani et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We study the adsorption of hydrogen molecules on a titanium atom supported by a benzene molecule using generalized gradient corrected Density Functional Theory (DFT). This simple system is found to bear important analogies with titanium adsorption sites in (8, 0) titanium-coated single-walled carbon nanotubes (SWNTs) (T. Yildirim and S. Ciraci, 2005) In particular, we show that up to four H2 molecules can coordinate to the metal ion center, with adsorption patterns similar to those observed in Ti-SWNTs and no more than one molecule dissociating in the process. We analyze in detail the orbital interactions responsible for Ti-benzene binding and for the electron transfer responsible for the H2 dissociation. We find the latter to involve a transition from a triplet to a singlet ground state as the hydrogen molecule approaches the adsorption site, similar to what has been observed in Ti-SWNTs. The total Ti-H2-binding energy for the first dissociative addition is somewhat inferior (~0.4 eV) to the value estimated for adsorption on Ti-SWNTs. We analyze in detail the orbital interactions responsible for the H2 binding.