ABSTRACT
The present study reports the synthesis of supported zeolite with nanoscopic size on the SiC-based composite combining nanoscopic properties, i.e., SiC nanofibers, and macroscopic shaping, i.e., SiC foam with centimeters size. The SiC nanofibers have been obtained by the transformation of the carbon nanofibers by carburization in the presence of SiO vapour and then the zeolite was deposited on the SiC foam support. The different nature of the support results in different morphologies on zeolite crystal.
ABSTRACT
In this study, we aimed to produce a highly selective and stable catalyst for the production of dimethyl ether by methanol dehydration. The activities were compared of different active phases of the employed system, zeolite HZSM-5 or gamma-alumina, supported on silicon carbide as foam, and it was found that the supported zeolite catalysts are more active than and as selective as the alumina-based catalysts. The as-prepared zeolite/SiC composites reveal good stability in long-term tests in the presence or absence of steam. The high stability is attributed to the presence of highly dispersed micrometer-sized zeolite particles, which make the active sites more accessible to the reactants and promote the quick transfer of the desired product, dimethyl ether, out of the catalyst bed, minimizing deactivation of the catalyst.
