Two-dimensional hetero-structures: on the reaction between MoS2 and graphene

Little is understood of the chemical interactions between nanomaterials in 2D hetero-structures of transition metal dichalcogenides and graphene. We prepared hetero-structures of MoS2 and graphene. X-ray photoelectron spectroscopy of the hetero-structures revealed an increase in an sp3-hybridized C component in the graphene component, while infra-red spectroscopy showed O–H, C=C, C–O and C–H moieties, which were not found in pristine graphene or MoS2. Thermogravimetric analysis of the hetero-structures showed thermal instability and carbonaceous decay at lower temperatures than in pristine precursors. We thus demonstrate a chemical change to graphene in such hetero-structures and offer evidence for a chemically non-innocent interaction between graphene and MoS2. Our discovery demonstrates the potential chemical non-innocence behaviour of 2D nanomaterials in hetero-structured devices.