RESUMEN
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, (29)Si magic-angle spinning (MAS) NMR spectroscopy, and mercury-intrusion porosimetry analyses. Silica and SiO(x)C(y) 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.
RESUMEN
Structured catalysts of mesoporous ZSM-5 matrixed over silicon carbide were successfully prepared and the obtained structured-zeolitic-catalyst has a multimodal porosity. This method also provided a means to immobilize catalytically active CNTs onto shape-tunable inorganic substrates.
RESUMEN
The structured catalyst of zeolite MCM-22/silicon carbide (SiC) was prepared for the first time through the in situ hydrothermal synthesis approach. The zeolite loading of the structured catalyst could be tuned by changing the synthesis time and applying alkali pre-treatment of SiC substrate. An additional silica layer formed on SiC substrate after the precalcination treatment facilitated the crystallization of MCM-22 zeolite on the SiC substrate. The MCM-22/SiC structured catalyst thus prepared exhibited good catalytic performance in the methane dehydroaromatization reaction.