Size controllable synthesis of hard carbon spheres from aqueous D-glucose

Carbon particles (CPs) with regular spherical shape have intensive potential applications. Carbon spheres (CSs) with controllable sizes from 90 to 490 nm were prepared by hydrothermal process. The effects of hydrothermal parameters namely, concentration of glucose (0.1~0.9 mol/L), reaction temperature (170°C~190°C) and reaction time (1~6 hr) on both size and dispersity of CSs were investigated. The surface groups of CSs were tested by FTIR. Hard carbon spheres (HCSs) were prepared by carbonising CSs in tube furnace at 1,000°C for 10 hours under inert argon atmosphere. XRD and SEM were employed to determine the structure and morphologies of these HCSs. The functions between the particle size and the reaction parameters were fitted and analysed based on carefully calibrations of the HCSs. It is established that the size of the HCSs increases exponentially with reaction temperature and time, but almost lineally with concentration. The results provide a route to controllably synthesise the carbon spheres in an array of sizes and dispersity by adjusting parameters.