화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.137, No.24, 7678-7685, 2015
Tuning the Magnetic Properties of Carbon by Nitrogen Doping of Its Graphene Domains
Here We-present the formation of predominantly sp(2)-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;lay a chemistry free of hydrogen and oxygen compared 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 omits 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 10-30 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 sp(2)-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 pi-electron density of edge states.