Facile preparation of hierarchically porous carbon monoliths with well-ordered mesostructures

By integration of gel casting with chemical vapor deposition (CVD), hierarchically porous carbon monoliths with either hexagonal or cubic mesostructures are prepared starting from well-ordered mesoporous silica powders (SBA-15 and KIT-6). Powdery silica particles are first fused together to form silica monoliths by the gel-casting method. Furfuryl alcohol at various concentrations in trimethylbenzene is used as carbon precursor. The use of low concentration of furfuryl alcohol, together with a secondary loading of carbon by the CVD method, allows an additional level of control over the hierarchical porosity of carbon monoliths. In addition, monolithic carbon materials with connected hexagonally packed nanopipes are fabricated for the first time here from large-pore SBA-15. The carbon monoliths exhibit macroporosity, well-ordered mesoporosity with either hexagonal or bicontinuous cubic symmetry, and controlled microporosity. The method described can be extended to prepare other types of carbon monoliths with different symmetries when appropriate silica templates with a connected pore system (e.g., MCM-48, SBA-16, and NaY) are applied.