Metallized siligraphene nanosheets (SiC7) as high capacity hydrogen storage materials
- 137 Downloads
A planar honeycomb monolayer of siligraphene (SiC7) could be a prospective medium for clean energy storage due to its light weight, and its remarkable mechanical and unique electronic properties. By employing van der Waals-induced first principles calculations based on density functional theory (DFT), we have explored the structural, electronic, and hydrogen (H2) storage characteristics of SiC7 sheets decorated with various light metals. The binding energies of lithium (Li), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca),scandium (Sc), and titanium (Ti) dopants on a SiC7 monolayer were studied at various doping concentrations, and found to be strong enough to counteract the metal clustering effect. We further verified the stabilities of the metallized SiC7 sheets at room temperature using ab initio molecular dynamics (MD) simulations. Bader charge analysis revealed that upon adsorption, due to the difference in electronegativity, all the metal adatoms donated a fraction of their electronic charges to the SiC7 sheet. Each partially charged metal center on the SiC7sheets could bind a maximum of 4 to 5 H2 molecules. A high H2 gravimetric density was achieved for several dopants at a doping concentration of 12.50%. The H2binding energies were found to fall within the ideal range of 0.2–0.6 eV. Based on these findings, we propose that metal-doped SiC7 sheets can operate as efficient H2 storage media under ambient conditions.
Keywordsclean energy functionalization binding characteristics dopants
Unable to display preview. Download preview PDF.
We are indebted to the Swedish Research Council (VR), StandUp, Swedish Energy Agency, and Swedish Institute for financial support. The SNIC and UPP-MAX are also acknowledged for providing computing time. T. Hussain is thankful to UQ for providing the financial support under UQ postdoctoral fellowship scheme and the resources at NCI National Facility systems at the Australian National University through National Computational Merit Allocation Scheme supported by the Australian Government and the University of Queensland Research Computing Centre.
- Van den Berg A. W.; Areán, C. O. Materials for hydrogen storage: Current research trends and perspectives. Chem. Commun. 2008, 668–681.Google Scholar
- US Department of Energy Office of Energy Efficiency and Renewable Energy and The FreedomCAR and Fuel Partnership. Targets for onboard hydrogen storage systems for light-duty vehicles [Online]. http://www1.eere.energy.gov/hydrogenandfu-elcells/storage/pdfs/targets_onboard_hydro_storage_explanation.pdf (accessed March 2017).Google Scholar
- Bader, R. F. W. Atoms in Molecules: A Quantum Theory; Oxford University Press: Oxford, 1990.Google Scholar