Carbon onions have been successfully synthesized via thermal reduction of glycerin with magnesium at 650 degrees C. The obtained carbon onions have diameters ranging from 60 to 90 mn. X-ray diffraction (XRD) and Raman spectroscopy analyses confirm that the carbon material has graphite feature and polycrystalline structure. (c) 2005 Elsevier B.V. All rights reserved.