Open AccessHydrogen-Driven Cage Unzipping of C60 into Nano-Graphenes
Author(s) -
Alexandr V. Talyzin,
Serhiy M. Luzan,
Ilya V. Anoshkin,
Albert G. Nasibulin,
Esko I. Kauppinnen,
Andrzej Dzwilewski,
Ahmed Kreta,
J. Jamnik,
A. Hassanien,
Anna Lundstedt,
Helena Grennberg
Publication year - 2014
Publication title -
journal of physical chemistry. c./journal of physical chemistry. c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/jp500377s
Subject(s) - raman spectroscopy , graphene , fourier transform infrared spectroscopy , materials science , analytical chemistry (journal) , hydrogen , infrared spectroscopy , fullerene , annealing (glass) , chemistry , chemical engineering , nanotechnology , organic chemistry , physics , engineering , optics , composite material
Annealing of C 60 in hydrogen at temperatures above the stability limit of C-H bonds in C 60 H x (500-550 °C) is found to result in direct collapse of the cage structure, evaporation of light hydrocarbons, and formation of solid mixture composed of larger hydrocarbons and few-layered graphene sheets. Only a minor part of this mixture is soluble; this was analyzed using matrix-assisted laser desorption/ionization MS, Fourier transform infrared (FTIR), and nuclear magnetic resonance spectroscopy and found to be a rather complex mixture of hydrocarbon molecules composed of at least tens of different compounds. The sequence of most abundant peaks observed in MS, which corresponds to C 2 H 2 mass difference, suggests a stepwise breakup of the fullerene cage into progressively smaller molecular fragments edge-terminated by hydrogen. A simple model of hydrogen-driven C 60 unzipping is proposed to explain the observed sequence of fragmentation products. The insoluble part of the product mixture consists of large planar polycyclic aromatic hydrocarbons, as evidenced by FTIR and Raman spectroscopy, and some larger sheets composed of few-layered graphene, as observed by transmission electron microscopy. Hydrogen annealing of C 60 thin films showed a thickness-dependent results with reaction products significantly different for the thinnest films compared to bulk powders. Hydrogen annealing of C 60 films with the thickness below 10 nm was found to result in formation of nanosized islands with Raman spectra very similar to the spectra of coronene oligomers and conductivity typical for graphene.