Vapor assisted 'in situ' transformation of mesoporous carbon-silica composite for hierarchically porous zeolites

摘要

Ordered mesoporous carbon-silica composite was "in situ" transformed into hierarchically porous zeolites ZSM-5 (H-ZSM-5) under water vapor, which synthesized from evaporation induced "tri-constituent" co-assembly of resin, silica and surfactant. The vapor assisted transformation was realized within 2-D hexagonally mesochannels of carbon-silica composite infused with tetrapropylammonium hydroxide at 130 °C for 72 h. The calcined H-ZSM-5-570 possesses a mesostructure with mean pore sizes of 0.6 and 9.0 nm, BET surface area of 409 cm~2/g, and pore volume of 0.54 cm~3/g. High-resolution TEM images of H-ZSM-5-570 display that mesoporous walls consisted of zeolite nanocrystals of about 6 nm in the same domain. Weak acidity of H-ZSM-5-570 has also been concluded from ammonia desorption measurements.