(C1.04H)n: A nearly perfect pure graphane

Hydrogenated graphene is an important graphene derivative with semiconductor properties. A novel and convenient approach via defluorination and hydrogenation of fluorographite, not previously used Birch-type reduction, is developed to prepare highly hydrogenated graphene in ethylenediamine at room temperature via wet-chemical reduction of commercially available fluorographite containing electropositive C atoms in polar CF bonds, using NaK alloy as reductant and isopropanol as quenching agent. The hydrogen content of our sample is 7.28 wt%, higher than any value ever reported, and its chemical composition can be identified as (C1.04H)n, which is quite close to theoretical graphane of (C1.00H)n. Moreover, band gap of hydrogenated graphene was found to be highly related with its H content. All these results provide potential resources towards new semiconductor materials and devices.