Metal-modified fluorographene stores hydrogen
doi:10.1038/nindia.2015.85 Published online 24 June 2015
Using a computer model, researchers have shown that fluorographene modified with light metals can be used to store hydrogen molecules1. Their calculations indicate that the materials obtained by attaching light metals such as lithium and sodium to either side of fluorographene efficiently adsorb hydrogen. Hydrogen stored in this manner could be used as an eco-friendly fuel.
To find an effective hydrogen-storage material, the researchers used the computer model to simulate structures of fluorographene monolayers in which light metal atoms replaced a few of the fluorine atoms.
The fluorographene monolayer consisted of eight carbon and eight fluorine atoms, two of which atoms (one each from either side) were substituted by atoms of lithium or sodium. Since both lithium and sodium atoms have a lower electronegativity than the carbon atoms to which these metal atoms were attached, charge could be transferred from the metal atoms to fluorographene.
The scientists found that the carbon atoms acquired a most of this transferred charge and the remaining charge went to the fluorine atoms, generating positive charges in the metal atoms. These positively charged metal atoms then bound to hydrogen molecules through weak electrostatic interactions and van der Waals forces.
“Each metal atom can bind to four hydrogen molecules on either side of the fluorographene, making it an excellent hydrogen-storing material,” says Rajeev Ahuja, one of the researchers.
The authors of this work are from: Uppsala University, Uppsala and Royal Institute of Technology, Stockholm, Sweden; Indian Institute of Technology Bombay, Mumbai and Hindustan University, Chennai, India; Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Australia and Dongguk University, Seoul, Korea.
1. Hussain, T. et al. Hydrogen storage properties of light metal adatoms (Li, Na) decorated fluorographene monolayer. Nanotechnology 26, 275401 (2015)