Template-Synthesized Porous Silicon Carbide as an Effective Host for Zeolite Catalysts

A facile method has been developed for the fabrication of porous silicon carbide (SiC) by means of sintering a mixture of SiC powder and carbon pellets at a relatively lower temperature, that is, 1450 degrees C, in air. The pore density and the total pore volume of the resulting porous SiC could be tuned by changing the initial SiC/C weight ratio. The structure evolution and the associated property changes during the preparation were examined through X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, Si-29 magic-angle spinning (MAS) NMR spectroscopy, and mercury-intrusion porosimetry analyses. Silica and SiOxCy ceramics formed in situ during the calcination process acted as binders of the porous SiC grains. The porous SiC can be used as a host for the growth of ZSM-5 zeolite crystals to form the ZSM-5/porous-SiC composite material. After loading another catalytic active component of molybdenum, a novel catalytic material, Mo-ZSM-5/porous-SiC, was obtained, which exhibited improved catalytic activity in the methane dehydroaromatization reaction.