Effect of Copper Substrate Surface Orientation on the Reductive Functionalization of Graphene

Although substrate composition can influence the chemical reactivity of graphene, substrate lattice orientation provides a valuable alternative. The effect of Cu surface orientation on the reactivity of graphene was explored through a reductive transformation. Among the substrates tested, only Cu(111) led to the efficient, fast and uniform functionalization of graphene, as demonstrated by Raman mapping, and this arose from compressive strain induced by Cu(111). Functionalization effectively relaxes the strain, which can be subsequently reintroduced after thermal treatment. Theoretical calculations showed how compression facilitates the reduction and hybridization of carbon atoms, while coupling experiments revealed how kinetics may be used to control the reaction. The number of graphene layers and their stacking modes were also found to be important factors. In a broader context, a description of how graphene undergoes chemical modification when positioned on certain metal substrates is provided.