Abstract: Carbon microspheres were successfully synthesized by introducing cetyltrimethylammonium bromide (CTAB) and citric acid during the hydrothermal carbonization of glucose. The carbon microspheres were characterized using SEM, XRD, Raman spectroscopy, and the four-probe method. When hydrothermally treated alone, citric acid did not lead to the formation of a solid product. Instead, it primarily served as a catalyst, which significantly facilitated the carbonization and growth of carbon microspheres, resulting in an enhanced yield and enlarged particle size.However, the introduction of CTAB resulted in a competitive effect between its templating function and the catalytic role of citric acid, causing a slight decrease in yield, while the spatial hindrance effect of CTAB restricted the radial growth of carbon microspheres, reducing their particle size. All samples exhibited a typical hard carbon disordered structure with low crystallinity. As the thermal treatment temperature increased, the defect level in some samples was enhanced, which might be related to the initial molecular structure of the carbon source and the removal of oxygen atoms, as well as the rearrangement of carbon atoms. Although the addition of citric acid and CTAB showed certain enhancing effect on conductivity, the effect of the thermal treatment temperature onconductivity was found to be more significant. Therefore, in practical applications, the conductivity of carbon microspheres should be primarily regulated through the optimization of the thermal treatment process, with the selection of thermal treatment temperature being particularly crucial.

Key words: glucose, hydrothermal carbonization, cetyltrimethylammonium bromide, citric acid, morphology, structure, conductivity