Efficient synthesis and sulfonation of ordered mesoporous carbon materials

Ordered mesoporous carbons (OMCs) with hexagonal structure were efficiently synthesized via cooperative self-assembly of phenol/formaldehyde resol and surfactant F127 under acidic aqueous conditions. Induced by HCl, a gel phase mainly containing phenol/formaldehyde resol and F127 was obtained within several hours. X-ray diffraction (XRD), transmission electron microscope (TEM) and nitrogen adsorption isotherms indicated that the synthesized samples possess 2-D hexagonal mesostructure. The influence of the synthesis conditions, including acid concentration and mass ratio of resol to F127, was investigated. When the acid concentration was fixed in the range of 0.6-2.0 M and the mass ratio of resol to F127 in the range of 3.5-4.0, highly ordered mesoporous carbon could be synthesized. The synthesized OMCs could be easily sulfonated in concentrated sulfuric acid at elevated temperature. The results indicate that the mesostructural stability and the content of the surface sulfonic acid (SO(3)H) groups depend mainly on the pyrolysis temperature of the OMCs and the sulfonation temperature, suggesting that the combination of pyrolysis and sulfonation temperature is essential for developing OMCs with high densities of SO(3)H groups.