Tuning the Magnetic Properties of Carbon by Nitrogen Doping of Its Graphene Domains

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• 作者：Yoshikazu Ito ; Christos Christodoulou ; Marco V. Nardi ; Norbert Koch ; Mathias Kl盲ui ; Hermann Sachdev ; Klaus M眉llen
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：June 24, 2015
• 年：2015
• 卷：137
• 期：24
• 页码：7678-7685
• 全文大小：498K
• ISSN：1520-5126

文摘

Here we present the formation of predominantly sp²-coordinate carbon with magnetic- and heteroatom-induced structural defects in a graphene lattice by a stoichiometric dehalogenation of perchlorinated (hetero)aromatic precursors [hexachlorobenzene, C₆Cl₆ (HCB), and pentachloropyridine, NC₅Cl₅ (PCP)] with transition metals such as copper in a combustion synthesis. This route allows the build-up of a carbon lattice by a chemistry free of hydrogen and oxygen compared to other pyrolytic approaches and yields either nitrogen-doped or -undoped graphene domains depending on the precursor. The resulting carbon was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, photoelectron spectroscopy (XPS), and SQUID magnetometry to gain information on its morphological, chemical, and electronic structure and on the location of the nitrogen atoms within the carbon lattice. A significant lowering of the magnetization was observed for the nitrogen-doped carbon obtained by this method, which exhibits less ordered graphene domains in the range of approximately 10鈥?0 nm as per TEM analysis compared to the nondoped carbon resulting from the reaction of HCB with larger graphene domains as per TEM and the presence of a 2D mode in the Raman spectra. The decrease of the magnetization by nitrogen doping within the sp²-coordinate carbon lattice can be attributed to an increase in pyrrole-type defects along with a reduction in radical defects originating from five-membered carbon ring structures as well as changes in the 蟺-electron density of edge states.