First theorized in 2006 as a derivative of graphene, graphane (also referred to as hydrogenated graphene) is an extended two-dimensional material consisting of a single layer of fully saturated (sp3 hybridization) carbon atoms.1 In 2009, a team that included the University of Manchester researchers who discovered graphene in 2004 reported the hydrogenation and possible synthesis of graphane by adding hydrogen atoms to graphene, turning the material into an insulator.2
Figure 1: Graphane is obtained from graphene (a monolayer of carbon atoms) by attaching hydrogen atoms (red) to each carbon atoms (blue) in the crystal (Source: University of Manchester)
Most of the potential applications and amazing propertieds of graphene are related with these partially hydrogenated structures and are primarily focused on electronics and hydrogen storage. Additional applications have been hypotesised in nanosensors and nanocomposites.3
Electronics
Graphane is a semiconductor with an energy gap, obtained from hydrogenation of the two-dimensional graphene sheet and displays potential for use as insulation materials for graphene-based electronic devices. The electronic band gap opened upon hydrogenation can be used to create channels and nanostructures of high mobility graphene supported by an insulating graphane matrix, allowing the system to act as a wide gap semiconductor with magnetic properties, high-temperature electron-photon superconductivity, giant Faraday rotation and the possible creation of quantum dots as vacancy clusters in the graphane body.4
Hydrogen storage
Due to the materials huge hydrogen density, graphane has been considered as potentially important for hydrogen storage. The advantage of utilizing graphane as substrate to bind metal adatoms for storing hydrogen is the strong metal-graphane bonding. 56 Research has shown that graphane can adsorb as many as four hydrogen molecules per Li, Na, and K metal atom. These values correspond to 12.20, 10.33, and 8.56 wt% of hydrogen, respectively, and exceed the DOE requirements. Li-graphane complex is the most promising for hydrogen storage with the ability to adsorb three hydrogen molecules per metal atom at 300 K and pressure in the range of 5–250 atm.7
Sources:
1. D. C. Elias et al. (2009). “Control of Graphene’s Properties by Reversible Hydrogenation: Evidence for Graphane”. Science 323(5914): 610-3. arXiv:0810.4706. Bibcode 2009Sci…323..610E. doi:10.1126/science.1167130. PMID 19179524.
2. Graphane: a two-dimensional hydrocarbon, J. O. Sofo, A. S. Chaudhari, and G. D. Barber, Phys. Rev. B 75, 153401 (2007).
3. Thickness and in-plane elasticity of graphane, F. Scarpa, R. Chowdhury, S.Adhikari, Physics Letters A 375(2011), 2071-2074.
4. Graphane as polyhydride of graphene. Computational synthesis applied to two-side membrane, Elena F Sheka and Nadezhda A Popova
5. . Hussain, B. Pathak, T. A. Maark, C. M. Araujo, R. H. Scheicher, and R. Ahuja, , Euro. Phys. Lett., 2011, 96, 27013.
6. M. Khanzai, M. S. Bahramy, N. S. Venkataramanan, H. Mizuseki and Y. Kawazoe, J. Appl. Phys. Lett., 2009, 106, 094303.
7. High hydrogen-adsorption-rate material based on graphane decorated with alkali metals, Phys. Rev. B 86, 085435
