Preparation and characterization of ordered mesoporous carbon membranes

Novel carbon membranes with a hexagonal structure were fabricated directly by the carbonization of sulfuric-acid-treated surfactant/silica nanocomposite membranes and subsequent silica removal. The nanocomposite membranes were prepared by dip coating technique through a combination of sol-gel and evaporation-induced self-assembly process. The samples were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), N₂ adsorption-desorption, and thermogravimetric analysis (TGA). These analyses reveal that the carbon membranes are composed of carbon nanotubes arrays and have continuous, smooth and ordered symmetric structure. The surfactant triblock copolymer P123 has dual functions in the sol-gel process. One is the structure directing and the other is carbon precursor. Pretreatment with sulfuric acid is a key step to improve the carbon yield of P123 and to stabilize the structure of carbon membranes. At the same time, by varying the aging temperature of nanocomposite membrane, it is possible to control the size of ordered carbon membrane.