Reactivity of Substrate-Supported Graphene: A Case Study of Hydrogenation

Using density-functional theory, we study the adsorption and reaction of hydrogen and single-sided graphene. This is a graphene sheet that is accessible for chemical reaction from only one side, whereas the other side is occupied by a substrate. Motivated by our earlier study on the hydrogenation and dehydrogenation of graphene on Ni(111), we choose graphene on Ni(111) as well as a system intercalated by gold, as representative models for strongly and weakly interacting surfaces and compare it with the free-standing reference case. We demonstrate that the structural alignment of graphene on a substrate and the substrate itself; both play a major role on the reactivity of metal-supported graphene, drastically changing the obtained reaction patterns and expected maximal coverages. Specific substrates can stabilize reaction patterns that would otherwise lead to unfavorable spin structures. We present a systematic way of studying the reactivity of such single-sided graphene, which is not limited to hydrogenation on the selected substrates but should also be applicable to predict the reactivity of graphene supported by other substrates and toward other reagents.