Papers by Author: Qun Xu

Abstract: Uniform cyclomatrix polyphosphazene spheres with diameter of about 410 nm were firstly synthesized rapidly at room temperature by precipitation polymerization of hexachlorocyclotriphosphazene with 4,4′-sulfonyldiphenol, using triethylamine as acid-acceptor and acetonitrile as solvent. Then, monodisperse carbon spheres with abundant micropores were produced by carbonization of the polyphosphazene spheres at a high temperature under a nitrogen atmosphere. As-produced carbon spheres were well characterized by SEM, TEM, EDX, and N2 adsorption technique. Results show that the carbon spheres possess an average diameter of 320 nm, a BET surface area of about 752 m2·g-1, a total pore volume of 0.55 m3·g-1, and a micropore size distribution.

Abstract: Hollow carbon hemispheres (HCHs) were synthesized at 500 oC in the magnesium carbonate-metallic Li system with the help of CHBr3. The product was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and field emission scanning electron microscope (FESEM). XRD and electron diffraction (ED) pattern results showed that HCHs were graphite phase and polycrystalline. By FESEM and TEM observation, the diameters of the HCHs were in the range of 200-900 nm. The shell of the HCHs was single-layer and their thickness was about 31 nm. The formation mechanism of HCHs with the help of CHBr3 was discussed. Besides, the effect of reaction temperature and dosage of CHBr3 on the morphology of HCHs was studied.