Structure and hydrogen adsorption properties in low density nanoporous carbons from simulations

Journal Article · Sun Jan 01 04:00:00 EST 2012 · Carbon

DOI:https://doi.org/10.1016/j.carbon.2011.11.012· OSTI ID:1031533

Peng, L. ^[1]; Morris, James R ^[2]

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1. University of Tennessee, Knoxville (UTK)
2. ORNL

We systematically model the hydrogen adsorption in nanoporous carbons over a wide range of carbon bulk densities (0.6 - 2.4 g/cm3) by using tight binding molecular dynamics simulations for the carbon structures and thermodynamics calculations of the hydrogen adsorption. The resulting structures are in good agreement with the experimental data of ultra-microporous carbon (UMC), a wood-based activated carbon, as indicated by comparisons of the microstructure at atomic level, pair distribution function, and pore size distribution. The hydrogen adsorption calculations in carbon structures demonstrate both a promising hydrogen storage capacity (excess uptake of 1.33 wt% at 298K and 5 MPa, for carbon structures at the lower range of densities) and a reasonable heat of adsorption (12-22 kJ/mol). This work demonstrates that increasing the heat of adsorption does not necessarily increase the hydrogen uptake. In fact, the available adsorption volume is as important as the isosteric heat of adsorption for hydrogen storage in nanoporous carbons.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1031533
• Journal Information: Carbon, Journal Name: Carbon Journal Issue: 3 Vol. 50; ISSN 0008-6223; ISSN CRBNAH
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
ACTIVATED CARBON
ADSORPTION
ADSORPTION HEAT
CAPACITY
CARBON
DISTRIBUTION
DISTRIBUTION FUNCTIONS
HYDROGEN
HYDROGEN STORAGE
MICROSTRUCTURE
THERMODYNAMICS