Preparation and characterization of pillared carbons obtained by pyrolysis of silylated graphite oxides

摘要

Pillared carbons were prepared by pyrolyzing various graphite oxides silylated by 3-amino-propylmethyldiethoxysilane.They were formed when silylated graphite oxides with silicon contents of 12.6% or higher were pyrolyzed in vacuo at 500-600 °C.Their interlayer spacings were 1.23-1.31 nm.When silylated graphite oxide was prepared at 90 °C,the reductive decomposition of graphite oxide by amino groups of 3-aminopropylmethyldiethoxysilane was suppressed and pillared carbon with higher crystallinity was obtained.At higher temperatures of pyrolysis,silylated graphite oxide decomposed to residual carbon without pillars.The pillars between the carbon layers contained methyl groups originating from the 3-aminopropylmethyldiethoxysilane.Based on the interlayer spacing and elemental analysis data,a structure model for the pillar is proposed.Pillared carbons showed type IV nitrogen adsorption isotherms and they contained both mesopores and a small volume of micropores.The BET surface area of the pillared carbon reached a maximum value of 236 m~2/g,when it was prepared from graphite oxide silylated at 105 °C for 20 days.