Abstrakt
Zeolite monolayers in solution, reported recently for the framework MWW, enable unprecedented synthetic capabilities that include preparation of molecularly intimate mixtures of different zeolite topologies. As a demonstration, MWW-MFI hybrid materials were synthesized by two methods: in-situ crystallization of MFI by adding the template and silica to solutions of MWW monolayers obtained from the zeolite MCM-56, and ex-situ by mixing the solutions of MWW layers with MFI crystals.
Catalytic activity of the mixtures was similar to un-diluted pure MWW despite high content of siliceous MFI, which was inert. This suggests that pure MWW layers do not provide optimal packing and accessibility of active sites and can be more efficiently utilized in combi-nation with other components.
The mixture of MCM-56 and MFI crystals was 50% less active. Practical benefits may be possible by combining frameworks with different types of activity in catalysis and sorption applications.
The mixtures were characterized by the standard methods: X-ray powder diffraction, TEM and SEM imaging, gas adsorptions and FTIR, which showed properties of both the MWW and MFI features with high acid activity and porosity.