Preparation Of Hollow Carbon Spheres

Due to their unique properties, such as chemical stability, thermal insulation, low weight, and high compressive strength, hollow carbon spheres are used in many fields, including electrode, storage for hydrogen or energy, absorbents, lubricants, supports of catalytic systems and so forth. Therefore, many scientific researches from academic and industrial fields have been carried out in this area.In this paper, styrene, commercial purchased furfural alcohol, and commercial purchased Phenolic Formaldehyde (PF) resins were used as material to prepare hollow carbon spheres by steps as follows; the synthesis and sulfonation of Polystyrene, the preparation of composite spheres, and carbonization. The structure and morphology of Polystyrene, sulfonated Polystyrene and as-prepared products by carbonization were characterized by SEM and TEM pictures. And the relationship between sulfonation rate and sulfonation time were quantitively characterized by analysis of IR spectra.The result showed that the sulfonation of Polystyrene was affected by the methods of adding of reagents and the separation of products. At the time, when furfural alcohol was used as carbon resource, the products were not well enough in our experiment, while commercial purchase PF resin was used, the well-prepared hollow carbon spheres were achieved with uniformed diameter.The optimal conditions for synthesis of Polystyrene were: all the reagents, including the emulsifier, initiator, styrene and dispersion medium were added together before the reaction was carried out, and the products were separated by direct centrifugation. The as-prepared PS spheres were with the diameter of around 600nm. And after sulfonation, the diameter would reduce to 565nm.When the sulfonated PS spheres and commercial purchased PF resin were used as materials to prepare hollow carbon spheres, the final products would be affected by the sulfonation rate and the ratio of PF to templates. The diameter and thickness of the hollow carbon spheres would increase with the increase of sulfonation time and the ration of PF to templates. When the ratio of PF/templates equal to 2:1 were used, with the elongation of sulfonation time, the diameter of the final products would increase from 520nm to 565nm, while when templates S4 (sulfonated for 4 hours) were used, as the ratio of PF/templates change from 1.5:1 to 4:1, the diameter increased from 527nm to 575nm, and the thickness of the shell from 51nm to 83nm.