Protection from Below: Stabilizing Hydrogenated Graphene Using Graphene Underlayers

Abstract

We show that dehydrogenation of hydrogenated graphene proceeds much more slowly for bilayer systems than for single layer systems. We observe that an underlayer of either pristine or hydrogenated graphene will protect an overlayer of hydrogenated graphene against a number of chemical oxidants, thermal dehydrogenation, and degradation in an ambient environment over extended periods of time. Chemical protection depends on the ease of oxidant intercalation, with good intercalants such as Br demonstrating much higher reactivity than poor intercalants such as 1,2-dichloro-4,5-dicyanonbenzoquinone (DDQ). Additionally, the rate of dehydrogenation of hydrogenated graphene at 300 °C in H/Ar was reduced by a factor of roughly 10 in the presence of a protective underlayer of graphene or hydrogenated graphene. Finally, the slow dehydrogenation of hydrogenated graphene in air at room temperature, which is normally apparent after a week, could be completely eliminated in samples with protective underlayers over the course of 39 days. Such protection will be critical for ensuring the long-term stability of devices made from functionalized graphene.

Liquids relax and unify strain in graphene

“…Interestingly, comparison between the I D /I G distributions of h-G/water in Fig. 5b, e demonstrates that longer plasma exposure results in higher and less uniform hydrogenation of the graphene, which is in agreement with previous studies 52,53 . Even more pronouncedly than in the case of 10 s hydrogenation (Fig.…”

Raman maps reveal heterogeneous hydrogenation on carbon materials

“…15,32 Similar synthesis conditions have been used for the hydrogenation of graphene to produce graphane, or hydrogenated graphene. [37][38][39] Hence, the similarities observed between Raman features (Pos(G), FWHM(G), and I(D)/I(G)) of the HCl(1h) sample with reported in the literature for graphite oxide and the presence of hydrogen in the film are not surprising. Reduced graphene oxide has a Raman spectrum that is more similar to the one for graphene oxide than for graphene itself.…”

“…Therefore, hydrogen evolution was observed at the titanium electrode during the synthesis of the carbon film 15,32 . Similar synthesis conditions have been used for the hydrogenation of graphene to produce graphane, or hydrogenated graphene 37–39 . Hence, the similarities observed between Raman features ( Pos ( G ), FWHM ( G ), and I ( D ) /I ( G )) of the HCl(1h) sample with reported in the literature for graphite oxide and the presence of hydrogen in the film are not surprising.…”

Graphene Transfer: A Physical Perspective

“…Whitener et al showed that chemical hydrogenation of graphene decreases the conductivity of the material by several orders of magnitude, while simultaneously weakening the adhesion between graphene and substrates as diverse as metal growth substrates, silicon oxides, and polymers (Figure 6) [63]. Additionally, hydrogenation of graphene is reversible chemically and thermally [64][65][66][67][68], so that once the hydrogenated graphene is on the target substrate, it can be restored to pristine graphene, thereby completely avoiding the need for etchants or polymer support. Physically, these techniques share a commonality with water-based delamination of a wide variety of nanomaterials [69][70][71][72][73].…”