Carbon spheres prepared via solvent-thermal reaction method and their microstructures after high temperature treatment

Abstract

Carbon spheres with size of 50−300 nm were synthesized via a solvent-thermal reaction with calcium carbide and chloroform as reactants in a sealed autoclave. The morphologies and microstructures of carbon spheres before and after high temperature treatment (HTT) were characterized by X-ray diffractometry (XRD), scanning electronic microscopy (SEM), energy diffraction spectroscopy (EDS), and transmission electron microscopy (TEM). The formation mechanism of carbon spheres was discussed. The results indicate that the carbon spheres convert to hollow polyhedron through HTT. Carbon spheres are composed of entangled and curve graphitic layers with short range order similar to cotton structure, and carbon polyhedron with dimension of 50−250 nm and shell thickness of 15−30 nm. The change of solid spheres to hollow polyhedron with branches gives a new evidence for formation mechanism of hollow carbon spheres.

Synthesis of uniform and size-controllable carbon nanospheres by a simple hydrothermal method and fabrication of carbon nanosphere super-hydrophobic surface

“…4(d)) or at higher temperatures and longer times led to some morphologies like polyhedrons with rough surfaces. Existence of such morphologies is consistent with those reported by Huang and Kroto [2,10]. In order to understand the CS size reduction mechanism, it is necessary to consider the microstructure of CNSs that is explained and showed elsewhere [2,10,11].…”

“…Existence of such morphologies is consistent with those reported by Huang and Kroto [2,10]. In order to understand the CS size reduction mechanism, it is necessary to consider the microstructure of CNSs that is explained and showed elsewhere [2,10,11]. From those reports and the discussions in Section 3.1, one can conclude that every CNSs is constructed of too many two-dimensional graphitic curved and small flaks compacted over each other with an interlayer distance of about 3-4Å.…”

“…Many methods have been developed to synthesize the CS consisted of chemical vapor deposition [7], pyrolysis [8], hydrothermal [9], solvothermal [10] and chemical routs [11]. Each method has its own advantages and disadvantages.…”

Calcium Carbide: A Unique Reagent for Organic Synthesis and Nanotechnology

“…[91] Because the reaction that gave rise to acetylene required an acidic proton, compounds such as acids or chloroform (which release HCl when heated)c ould also be used fort his purpose. [92] Organica cids can also act as as ource of water molecules:f or example, oxalic acid forms calcium oxalate, thusc ontributing to acetylene release. This approachh as been used to produce nanospheres.…”