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 sp2 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. graphene edge single Fe atom catalytic anomalous diffusion TEM ACKNOWLEDGMENTS. We thank Prof. You-hua Luo (East China University of Science and Technology) for providing the Dmol3 code.We also thank Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden and in particular, the Institute for Solid State Research for use of their microscopy facilities. J.Z. thanks the Deutsche Akademische Austausch Dienst. Q.D. thanks the Deutsche Forschung Gemeinshaft (Project PO 1602/1-1). Sino-German Center for Research Promotion Grant GZ871 is acknowledged. This work was supported by Institute of Basic Sciences Korea Grant IBS-R011-D1.