Ordered mesoporous carbon molecular sieves by templated synthesis: the structural varieties

Ordered mesoporous carbons with various structures, designated as CMK-1~5, have been synthesized by carbonization of sucrose, furfuryl alcohol or other suitable carbon sources inside silica or aluminosilicate mesopores that are interconnected into three-dimensional networks such as in MCM-48 (cubic Ia3d), SBA-1 (cubic Pm3n) and SBA-15 (hexagonal p6mm). The mesoporous carbon molecular sieves, obtained after template removal with HF or NaOH solution, show transmission electron micrographs and X-ray diffraction patterns characteristic of the ordered arrangement of uniform mesopores. The structures of these novel carbon materials can be controlled to be negative carbon replicas (CMK-2 obtained from SBA-1, CMK-3 from SBA-15, and CMK-4 from MCM-48) or a network of nano-pipes obtained by uniform deposition of carbon films on the pore walls (CMK-5 from SBA-15), depending on the carbon sources. In a specific case of CMK-1, the synthesis using MCM-48 undergoes the structural transformation to two interpenetrating carbon networks (cubic Ia3d) to an interwoven structure (cubic I4132 or lower). The ordered mesoporous carbons, which are opening up a new area of the nanoporous materials, exhibit BET specific surface areas as high as 2200 mg, excellent thermal stability in inert atomospheres, strong resistance to attack by acids and bases (standing over a week in boiling 5 M aqueous solution of NaOH, KOH, or H2SO4).