title: Dual path mechanism in the thermal reduction of graphene oxide.
abstract: Graphene is easily produced by thermally reducing graphene oxide. However, defect formation in the C network during deoxygenation compromises the charge carrier mobility in the reduced material. Understanding the mechanisms of the thermal reactions is essential for defining alternative routes able to limit the density of defects generated by carbon evolution. Here, we identify a dual path mechanism in the thermal reduction of graphene oxide driven by the oxygen coverage: at low surface density, the O atoms adsorbed as epoxy groups evolve as O(2) leaving the C network unmodified. At higher coverage, the formation of other O-containing species opens competing reaction channels, which consume the C backbone. We combined spectroscopic tools and ab initio calculations to probe the species residing on the surface and those released in the gas phase during heating and to identify reaction pathways and rate-limiting steps. Our results illuminate the current puzzling scenario of the low temperature gasification of graphene oxide.
authors.affiliation: CNR-Institute for Complex Systems, Roma, Italy. rosanna.larciprete@isc.cnr.it
authors.forename: Rosanna
authors.initials: R
authors.lastname: Larciprete
authors.forename: Stefano
authors.initials: S
authors.lastname: Fabris
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.forename: Paolo
authors.initials: P
authors.lastname: Lacovig
authors.forename: Alessandro
authors.initials: A
authors.lastname: Baraldi
authors.forename: Silvano
authors.initials: S
authors.lastname: Lizzit
mesh_terms: D006108:Graphite / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D013696:Temperature
chemical_list: D010087:Oxides; D006108:Graphite