from first principles PP-I-1

OP-III-17Catalysis of Organic Reactions with Hydrogen on Graphene Activated bythe Presence of Defects and Metal SublayerLokteva E.S. 1 , Erokhin A.V. 1 , Yermakov A.Ye. 2 , Uimin M.A. 2 , Bukhvalov D. 31 Lomonosov Moscow State University, Moscow, Russia2 Institute of Metal Physics, Ural Division of RAS, Yekaterinburg, Russia3 School of Computational Sciences, Korea Institute for Advanced Study, Seoul, Koreales@kge.msu.ruAt present, many fundamental researches are directed to investigation of graphene due to itsunique properties. In this work, an attempt has been made to divide the catalytic properties inhydrogenation reactions of transition metals and graphene in model onion-like nanocompositesystems consisting of the 4-10 nm in size particles that include metal core and graphene shellof a few layers. Such systems were prepared by modified CCVD method including levitationmelting of metal wire with subsequent hot nanoparticles formation, on which graphene layerwas deposited by dissociation of hydrocarbons. Ni@C, Fe@C and NiPd@C systems wereprepared in this work. The structure and composition of nanocomposites were irrefragablycharacterized with Raman spectroscopy, HR TEM, synchronic thermal analysis (TGA, DTA,MS), Mossbauer spectroscopy, XRD, XAS.Catalytic tests in vapor-phase continuous flow hydrodechlorination (HDC) of chlorobenzeneand hydrogenation of phenylacetylene (PA) on fixed bed of Ni@C, Fe@C and NiPd@Cdemonstrate high conversion of substrate molecules at 150-350°C. Benzene was the onlyproduct of HDC irrespective of catalyst composition; styrene as desired product of PAhydrogenation formed on Ni@C and Fe@C. TEM investigation after repeated catalytic cyclesconfirms the integrity of graphene shell during catalytic tests and the absence of itsdestruction under the reaction conditions.The possibility of H 2 activation on graphene shell was demonstrated by various methods. DFTcalculations of pristine one and three-layer graphene and the same systems activated by metalsublayer and/or Stowne-Walls defects confirmed that activation energy was significantlyreduced due to both modification types. Experimental proof is the significant catalytic activityof Fe@C composite in both reactions in mild conditions. Additional proofs of the dissociativeH 2 adsorption on graphene shell were found using H-D exchange method.This work was supported by RFBR (№ 10-03-00372, 11-03-00820-а) and Leading ScientificSchools grant НШ-2724.2012.3. Results were obtained with the help of SRCCU“Nanochemistry and Nanomaterials” of Lomonosov Moscow State University.60