title: Direct in situ observations of single Fe atom catalytic processes and anomalous diffusion at graphene edges.
abstract: Single-atom catalysts are of great interest because of their high efficiency. In the case of chemically deposited sp(2) carbon, the implementation of a single transition metal atom for growth can provide crucial insight into the formation mechanisms of graphene and carbon nanotubes. This knowledge is particularly important if we are to overcome fabrication difficulties in these materials and fully take advantage of their distinct band structures and physical properties. In this work, we present atomically resolved transmission EM in situ investigations of single Fe atoms at graphene edges. Our in situ observations show individual iron atoms diffusing along an edge either removing or adding carbon atoms (viz., catalytic action). The experimental observations of the catalytic behavior of a single Fe atom are in excellent agreement with supporting theoretical studies. In addition, the kinetics of Fe atoms at graphene edges are shown to exhibit anomalous diffusion, which again, is in agreement with our theoretical investigations.
authors.affiliation: Institute of Complex Materials and Center for Integrated Nanostructure Physics, Institute for Basic Science and Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea;
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Institute of Solid State Research, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, D-01171 Dresden, Germany;
authors.forename: Qingming
authors.initials: Q
authors.lastname: Deng
authors.affiliation: Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX 78712;
authors.forename: Stanislav M
authors.initials: SM
authors.lastname: Avdoshenko
authors.affiliation: College of Chemistry and Molecular Science, Wuhan University, Wuhan, 430072, People's Republic of China; and.
authors.forename: Lei
authors.initials: L
authors.lastname: Fu
authors.affiliation: Institute of Complex Materials and Institute of Materials Science, Technical University Dresden, D-01062 Dresden, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Eckert
authors.affiliation: Center for Integrated Nanostructure Physics, Institute for Basic Science and Department of Energy Science, Department of Physics, Sungkyunkwan University, Suwon 440-746, Korea; mark@rummeli.com.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Rümmeli
mesh_terms: D006108:Graphite / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D037742:Nanotubes, Carbon / Q000737:chemistry*
chemical_list: D037742:Nanotubes, Carbon; D006108:Graphite; D007501:Iron
keywords: TEM; anomalous diffusion; catalytic; graphene edge; single Fe atom