Hydrogen storage in engineered carbon nanospaces
Open Access
- 24 April 2009
- journal article
- Published by IOP Publishing in Nanotechnology
- Vol. 20 (20), 204026
- https://doi.org/10.1088/0957-4484/20/20/204026
Abstract
It is shown how appropriately engineered nanoporous carbons provide materials for reversible hydrogen storage, based on physisorption, with exceptional storage capacities (approximately 80 g H2/kg carbon, approximately 50 g H2/liter carbon, at 50 bar and 77 K). Nanopores generate high storage capacities (a) by having high surface area to volume ratios, and (b) by hosting deep potential wells through overlapping substrate potentials from opposite pore walls, giving rise to a binding energy nearly twice the binding energy in wide pores. Experimental case studies are presented with surface areas as high as 3100 m(2) g(-1), in which 40% of all surface sites reside in pores of width approximately 0.7 nm and binding energy approximately 9 kJ mol(-1), and 60% of sites in pores of width>1.0 nm and binding energy approximately 5 kJ mol(-1). The findings, including the prevalence of just two distinct binding energies, are in excellent agreement with results from molecular dynamics simulations. It is also shown, from statistical mechanical models, that one can experimentally distinguish between the situation in which molecules do (mobile adsorption) and do not (localized adsorption) move parallel to the surface, how such lateral dynamics affects the hydrogen storage capacity, and how the two situations are controlled by the vibrational frequencies of adsorbed hydrogen molecules parallel and perpendicular to the surface: in the samples presented, adsorption is mobile at 293 K, and localized at 77 K. These findings make a strong case for it being possible to significantly increase hydrogen storage capacities in nanoporous carbons by suitable engineering of the nanopore space.Keywords
This publication has 23 references indexed in Scilit:
- Storage of hydrogen by physisorption on carbon and nanostructured materialsScripta Materialia, 2007
- Independent verification of the saturation hydrogen uptake in MOF-177 and establishment of a benchmark for hydrogen adsorption in metal–organic frameworksJournal of Materials Chemistry, 2007
- The U.S. Department of Energy's National Hydrogen Storage Project: Progress towards meeting hydrogen-powered vehicle requirementsCatalysis Today, 2007
- HIGH-SURFACE-AREA BIOCARBONS FOR REVERSIBLE ON-BOARD STORAGE OF NATURAL GAS AND HYDROGENMRS Proceedings, 2007
- Optimum Conditions for Adsorptive StorageLangmuir, 2006
- Nondissociative Adsorption ofMolecules in Light-Element-Doped FullerenesPhysical Review Letters, 2006
- Graphene nanostructures as tunable storage media for molecular hydrogenProceedings of the National Academy of Sciences of the United States of America, 2005
- Hydrogen Storage in Novel Organometallic BuckyballsPhysical Review Letters, 2005
- Storage of hydrogen on single-walled carbon nanotubes and other carbon structuresApplied Physics A, 2004
- Density functional theory investigation of H adsorption on the basal plane of boron-doped graphiteThe Journal of Chemical Physics, 2003