title: Reactivity of monolayer chemical vapor deposited graphene imperfections studied using scanning electrochemical microscopy.
abstract: Imperfections that disrupt the sp(2) conjugation of graphene can alter its electrical, chemical, and mechanical properties. Here we report on the examination of monolayer chemical vapor deposited graphene imperfections using scanning electrochemical microscopy in the feedback mode. It was found that the sites with a large concentration of defects are approximately 1 order of magnitude more reactive, compared to more pristine graphene surfaces, toward electrochemical reactions. Furthermore, we successfully passivated the activity of graphene defects by carefully controlling the electropolymerization conditions of o-phenylenediamine. With further electropolymerization, a thin film of the polymer was formed, and it was found to be insulating in nature toward heterogeneous electron transfer processes. The use of spatially resolved scanning electrochemical microscopy for detecting the presence and the "healing" of defects on graphene provides a strategy for in situ characterization and control of this attractive surface, enabling optimization of its properties for application in electronics, sensing, and electrocatalysis.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States.
authors.forename: Cen
authors.initials: C
authors.lastname: Tan
authors.forename: Joaquín
authors.initials: J
authors.lastname: Rodríguez-López
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Parks
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Ritzert
authors.forename: Daniel C
authors.initials: DC
authors.lastname: Ralph
authors.forename: Héctor D
authors.initials: HD
authors.lastname: Abruña
mesh_terms: D004563:Electrochemistry; D005296:Ferrous Compounds / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D000075163:Metallocenes; D008853:Microscopy; D058105:Polymerization; D014835:Volatilization
chemical_list: D005296:Ferrous Compounds; D000075163:Metallocenes; D006108:Graphite; C004998:ferrocene