ben's poster
TRANSCRIPT
Chun Hong Ben, Ng and Dr Luis Hererra
School of Chemical Engineering, The University of Adelaide.
Hydrogen storage enhancement on Li and K doped carbon
nanotubes
Introduction
Hydrogen is seen as the fuel for the future due to clean
combustion, renewability and high energy content
properties. However, the main issue concerning hydrogen
fuel is the limited storage capacity at room temperature
and pressure. In this work, unmodified and alkali modified
carbon nanotubes were simulated in order to identify a
suitable carbon structure that can meet the U.S.
Department of Energy (DOE) target of 6.5 wt% or 62 kg/m3
Hydrogen storage for automobile applications [1]. Grand
Canonical Monte Carlo simulation was used to simulate
the hydrogen adsorption isotherms of the carbon
structures under various pressures and ambient
temperature.
Aim To compare and identify the most suitable alkali modified
carbon nanostructure for enhanced hydrogen storage. This
is achieved by:
1) Determining Li and K dopant positioning on carbon
structures
2) Comparing single walled carbon nanotubes and
bundles for H2 storage
Based on the results, alkali doped carbon nanotubes have
higher hydrogen storage capacity as compared to
unmodified carbon structures. Carbon nanotube bundles
have higher interstitial forces between the carbon
nanotubes which resulted in larger storage than carbon
SWNT. Li doped carbon structures have slightly higher
hydrogen adsorption capacity than K doped carbon
structures. Both doped carbon structures met the DOE
target only at 10MPa conditions.
Future Work
To compare different dopant positioning of Li-doped
carbon nanotubes under cryogenic conditions.
References: [1] Yuan, X., et al., Monte Carlo simulation of hydrogen
physisorption in K-doped single walled carbon nanotube array.
Applied Surface Science, 2009. 255(18): p. 8122-8125.
Conclusion
Results
The hydrogen adsorption isotherms of unmodified and
alkali modified carbon nanotubes were generated from
Grand Canonical Monte Carlo simulation.
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Methodology
Structure Generation and Simulation Box Setup
Helium Gas Expansion Calculations
Isotherms Generation
Storage Capacity Calculation
Figure 1: Li-doped SWNT and bundle dopant positioning
Table 1: Lennard Jones parameters
Atom ε /k (K) σ (nm) Charges
C 28.20 0.3400 -
H 36.70 0.2958 At Figure 2
He 10.22 0.2556 -
K 421.0 0.4115 +0.83
Li 567.0 0.2728 +0.45
Figure 3: Snapshots of unmodified and Li-doped SWNT at 1MPa
+2.051 +2.051 -4.096
Figure 2: Dipole charges of H2 model