Synthesis and Characterization of Polyhedral Graphite Particles

Abstract

Hollow polyhedral graphite particles with 200~400 nm in diameter have been synthesized by heating oxalic acid, ferrocene and metallic magnesium at 580 °C, typically forming diamond-like octahedral structure. Combined with SEM, TEM, SAED patterns, and Raman spectroscopy, it was shown that the surface of graphite polyhedrons is composed of approximately 30-40 graphene shells; the four-or six-fold symmetric diffraction spots disclosed the nature of octahedral graphite particles; the edge of the graphite polyhedrons exists sp 3 -hybridized bonding, which would act as dangling bonds and localized defects in the polyhedron.

Carbon nanogears and nanotori via combustion flames

“…2-4, we can see that the folding of carbon crystals was not stochastic; rather, they followed certain crystallographic principles [4]. In previous investigations, needles, rods, rings, barrels and pyramids have been reported [4][5][6]. Several different structures collected on the Si substrate such as nanogears, nanotori, and spherical structures are discovered in our experiments.…”

“…Besides previously reported structures such as quadrilaterals [5], hexagons, [4], and anomalous structures [6], nanogears, nanotori, and microspherical structures are found in the depositions.…”

“…Furthermore, carbon nanotubes and graphene have been obtained on metal substrates such as Co [8], Ni [8][9][10], and Cu [10]. The existence of sp 2 and sp 3 bonds was verified by the Raman spectra [5][6][7][8][9]. Unknown micro-/nanostructures of carbon polyhedral crystals are still under exploration.…”

“…Diverse carbon nanomaterials, such as diamond/diamond-like ones [1][2][3], graphite polyhedral crystals [4][5][6], carbon nano thin films [7], carbon nanotubes [8] and graphene [9,10], have been widely investigated based on CF methods due to their extraordinary mechanical, optical and electrical properties. The diamond grains from micrometer [1,2] to millimeter scale [3] have been reported, which showed the potential applications of the CF for super hard materials.…”

“…The diamond grains from micrometer [1,2] to millimeter scale [3] have been reported, which showed the potential applications of the CF for super hard materials. The graphite polyhedral crystals exhibited unusual sevenfold, ninefold [4], octahedron [5] and more complex axial symmetry [6]. The ultra-thin carbon films on copper foils by the CF method have not only high transparency and flexibility, but excellent optoelectronic properties [7] as well.…”