title: Oxidation states of graphene: insights from computational spectroscopy.
abstract: When it is oxidized, graphite can be easily exfoliated forming graphene oxide (GO). GO is a critical intermediate for massive production of graphene, and it is also an important material with various application potentials. With many different oxidation species randomly distributed on the basal plane, GO has a complicated nonstoichiometric atomic structure that is still not well understood in spite of intensive studies involving many experimental techniques. Controversies often exist in experimental data interpretation. We report here a first principles study on binding energy of carbon 1s orbital in GO. The calculated results can be well used to interpret experimental x-ray photoelectron spectroscopy (XPS) data and provide a unified spectral assignment. Based on the first principles understanding of XPS, a GO structure model containing new oxidation species epoxy pair and epoxy-hydroxy pair is proposed. Our results demonstrate that first principles computational spectroscopy provides a powerful means to investigate GO structure.
authors.affiliation: Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wenhua
authors.initials: W
authors.lastname: Zhang
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Carravetta
authors.forename: Zhenyu
authors.initials: Z
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Luo
authors.forename: Jinlong
authors.initials: J
authors.lastname: Yang
mesh_terms: D002244:Carbon / Q000737:chemistry*; D003198:Computer Simulation; D004852:Epoxy Compounds / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011789:Quantum Theory
chemical_list: D004852:Epoxy Compounds; D010087:Oxides; D002244:Carbon