A controllable soft-templating approach to synthesize mesoporous carbon microspheres derived from D-xylose via hydrothermal method

Highly dispersed carbon microspheres (CMSs) derived from D-xylose were successfully synthesized under hydrothermal conditions and followed by further carbonization, in which F127 was used as a soft template. As-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), flourier transform infrared spectroscopy (FT-IR), thermal gravimetric (TG) and X-ray diffraction (XRD). The results showed that the morphology and structure of the CMSs prominently depended on the stirring speed during hydrothermal reaction. The resultant CMSs principally had non-porous structure without stirring and had a very smooth surface. When the stirring speed increased to 200 rpm, the synthesized mesoporous carbon microspheres at 220 degrees C for 24 h (CMSs-5) had a uniform size distribution of 1-1.4 pin and a specific surface area of 452 m(2)/g. Nevertheless, with further increasing to 400 rpm, as-fabricated carbon products were mostly amorphous with a low degree of sphericity. Results demonstrated that the diameter of the products decreased with the increase of stirring speed. Furthermore, the sphericity product yield of CMSs reduced with the increase of stirring speed. XRD result showed that all the obtained samples contained partial graphite phase. In addition, a formation mechanism was proposed that involved polymerization product as the precursors for microsphere formation. The controllable and green strategy may provide a great convenience to study properties and applications of carbon microspheres. (C) 2019 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.