First-principles study of hydrogenated graphyne and its family: Stable configurations and electronic structures

Graphyne is a new two-dimensional carbon allotrope consisting of sp- and sp2-hybridized carbon atoms. We performed first-principles calculations to study the stable configurations and the corresponding electronic structures of hydrogenated graphyne and its family. We found that at low coverage, hydrogen atoms prefer to chemically adsorb on the carbon atoms in the chains rather than on those in the hexagons. The hydrogen adsorption on graphyne is stronger than that on graphene. The band gap of hydrogenated graphyne is tunable in a wide range upon changing the hydrogen coverage. This implies a promising route to tune the electronic properties of graphyne and its family via attaching foreign atoms or functional groups into its scaffolding.

► Hydrogen atoms prefer to chemically adsorb on carbon in chains at low coverage. ► The hydrogen adsorption enhanced the stability of graphyne. ► Band gap of hydrogenated graphyne is tunable in a wide range. ► Some stable configurations of hydrogenated graphyne have been put forward. ► Rules found in hydrogenated graphyne still hold for the synthesized graphdiyne.