Pore size control of microporous carbon membranes by post-synthesis activation and their use in a membrane reactor for dehydrogenation of methylcyclohexane

Abstract Hydrogen-permselective carbon membranes were prepared by a vapor-phase synthesis using furfuryl alcohol as a carbon source. Their pore sizes were evaluated from the molecular sieving properties by single gas permeations of H 2 , CO 2 , CH 4 and CF 4 . The pore size of the carbon membranes was increased by a post-synthesis activation using various gases and vapors such as H 2 , CO 2 , O 2 and steam. The activation using H 2 was the most effective for improving both the H 2 permeance and permselectivity because the molecular size of H 2 is smaller than the pore size of the carbon membrane and can react with the inner surface of the carbon membrane. After the activation using H 2 at 973 K, the pore size of the carbon membrane was increased from 0.30 to 0.45 nm, and the permeance of H 2 was increased from 3.6×10 −9 to 1.6×10 −8  mol m −2  s −1  Pa −1 . The activated carbon membrane was used in a membrane reactor for dehydrogenation of methylcyclohexane and showed potential for application in the dehydrogenation of chemical hydrides in membrane reactors.