Hydrothermal Synthesis of Carbon Microspheres from Glucose: Tuning Sphere Size by Adding Oxalic Acid

Carbon spheres were successfully prepared via hydrothermal treatment of glucose, and spherical size (0.5–8 μm) could be tuned by adding different amount of oxalic acid. The surface of obtained carbon spheres contains hydrophilic functionalities including –OH, –C=O, and COOH groups, which were not destroyed by oxalic acid. This study provided a facile, simple route for producing size-tunable carbon microspheres with functional groups.