Bilayered
HZSM-5 zeolite coatings with additional nonzeolite pores
were synthesized on the inner surface of stainless steel tubes by
a secondary growth method with the addition of ethanol into the synthesis
batch. The as-synthesized coatings were characterized by scanning
electron microscopy and gas permeation, indicating that additional
nonzeolitic pores were formed in the presence of ethanol. A remarkable
greater than 1000-fold improvement in N2 permeation was
observed. Catalytic cracking of supercritical n-dodecane
(500 °C, 4 MPa) over a series of bilayered HZSM-5 coatings showed
that the HZSM-5 coatings with additional nonzeolite pores also exhibit
a remarkable catalytic activity improvement by ca. 150% and that the
amount of nonzeolite porosity may play a determining role in the enhancement
of the catalytic performance. According to cracking products and the
permeation test, the performance enhancement may be attributed to
the effective access of reactant to the acid sites in the zeolite
pores due to the enhanced diffusion of supercritical n-dodecane in the zeolite coatings with the nonzeolite pores.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.