Binderless zeolite coatings on macroporous α-SiC foams

Several syntheses have been performed to allow the growth of zeolite crystals on α-silicon carbide supports (α-SiC). Silicon-carbide foams exhibit a duplex macroporous structure. MFI and ANA zeolites have been successfully coated on this relatively inert material. While the synthesis of MFI/SiC required the presence of an additional Si-containing source, in contrast, ANA/SiC composites have been unexpectedly obtained through the self-recrystallization of the silicon contained in the α-SiC substrate. In addition, the size of icositetrahedral ANA crystals was controlled to nearly 35 μm, thanks to SiC open cells templating effect. The different composite materials were thoroughly characterized by SEM, complete textural analysis and XRD. The amount of zeolite coating as well as the coverage by ANA zeolite crystals on SiC surface were determined by both SEM observations and adsorption measurements.