Hierarchical zeolite microspheres with flat sheets, wave sheets or agglomerates induced by gemini surfactant counterion

Abstract The solution structure of a gemini surfactant, C 22-6-6 , associated with various counterions was investigated with small-angle neutron scattering (SANS). Subsequently, C 22-6-6 with various counterions (Br − , HC 2 O 4 − , C 2 O 4 2− , CO 3 2− , H 2 PO 4 − , HPO 4 2− and OH − ) was applied as a structure directing agent (SDA) in the synthesis of hierarchical zeolites. C 22-6-6 gemini surfactants form robust prolate (rod) micelles that only exhibit small changes in size with varying counterion, concentration, temperature and salt. Hierarchical MFI successfully crystallized with C 22-6-6 associated with various counterions as the SDA. The exception was for HC 2 O 4 − and H 2 PO 4 − which lowered the pH of the final synthesis solution. Different SDA counterions engender MFI zeolites with various morphologies, such as flat sheets, wave-like sheets, aggregates, micron sized spheres, and change the mesoporosity, total pore volume and silicon to aluminum ratio.