Condensed Matter Physics Seminar
Wed, Apr 03
12:15 PM — 1:15 PM
Marshak ScienceCity College of New York160 Convent Ave., New York, NY 10031
Marshak Science, 418N
"The influence of graphene curvature on hydrogen adsorption: towards hydrogen storage devices."The influence of graphene curvature on hydrogen adsorption:
towards hydrogen storage devices
Laboratorio NEST, Istituto Nanoscienze – CNR and Scuola Normale Superiore,
Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia,
Piazza San Silvestro 12, 56127 Pisa, Italy
Graphene is an intriguing material that shows promises for hydrogen storage. It is a single layer of carbon atoms arranged in a honeycomb lattice. I will introduce the current state of the art hydrogen storage materials followed by the possibility of using graphene as a scaffold for hydrogen. Theory predicts that the energy barrier for adsorbing and desorbing atomic hydrogen attached to the pi-bonds of graphene can be removed making it possible to attach and release hydrogen at room temperature, a mechanism that can be exploited for hydrogen storage applications . I will show experimental evidence that the energy barrier for adsorbing atomic hydrogen attached to the pi-bonds depends on the curvature of graphene.
To test these predictions, scanning tunneling microscopy experiments were performed on epitaxial graphene grown on SiC(0001) which has a periodic intrinsic curvature . The positions and stable conformations of the hydrogen atoms on the atomically resolved lattice were studied as a function of curvature by hydrogenating the sample in situ . It was found that atomic hydrogen binds to the carbon atoms in the convexly curved areas, as expected from DFT calculations . The desorption energy barrier of hydrogen on the maximally convex area of graphene was calculated . The curvature dependent graphene-hydrogen interaction results presented are an encouraging step towards a hydrogen storage device that adsorbs and releases hydrogen independent of temperature and pressure changes.
 V. Tozzini and V. Pellegrini. J. Phys. Chem. C 115, 25523 (2011).
 F. Varchon et al. Phys. Rev. B 77, 235412(2008).
 S. Goler et al. submitted for review.