title: Van der Waals force: a dominant factor for reactivity of graphene.
abstract: Reactivity control of graphene is an important issue because chemical functionalization can modulate graphene's unique mechanical, optical, and electronic properties. Using systematic optical studies, we demonstrate that van der Waals interaction is the dominant factor for the chemical reactivity of graphene on two-dimensional (2D) heterostructures. A significant enhancement in the chemical stability of graphene is achieved by replacing the common SiO2 substrate with 2D crystals such as an additional graphene layer, WS2, MoS2, or h-BN. Our theoretical and experimental results show that its origin is a strong van der Waals interaction between the graphene layer and the 2D substrate. This results in a high resistive force on graphene toward geometric lattice deformation. We also demonstrate that the chemical reactivity of graphene can be controlled by the relative lattice orientation with respect to the substrates and thus can be used for a wide range of applications including hydrogen storage.
authors.affiliation: Department of Physics, National University of Singapore , Singapore 117542, Singapore.
authors.forename: Jong Hak
authors.initials: JH
authors.lastname: Lee
authors.forename: Ahmet
authors.initials: A
authors.lastname: Avsar
authors.forename: Jeil
authors.initials: J
authors.lastname: Jung
authors.forename: Jun You
authors.initials: JY
authors.lastname: Tan
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Natarajan
authors.forename: Goki
authors.initials: G
authors.lastname: Eda
authors.forename: Shaffique
authors.initials: S
authors.lastname: Adam
authors.forename: Antonio H
authors.initials: AH
authors.lastname: Castro Neto
authors.forename: Barbaros
authors.initials: B
authors.lastname: Özyilmaz
mesh_terms: D004220:Disulfides / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D008956:Models, Chemical; D008982:Molybdenum / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D017973:Tungsten Compounds / Q000737:chemistry
chemical_list: D004220:Disulfides; D017973:Tungsten Compounds; D012822:Silicon Dioxide; D006108:Graphite; D008982:Molybdenum; C082964:molybdenum disulfide
keywords: 2D heterostructures; chemical reactivity; functionalization; graphene; hydrogen storage; van der Waals interaction