Colloidal Nanocrystals of Zeolite β Stabilized in Alumina Matrix

Characteristics of zeolite β in stable aqueous colloidal solution were measured by cryo-TEM, DLS, SAXS and after separation from solution by SEM, HR-TEM. Twenty-nanometer spherical zeolite crystals were measured in equilibrium with flocculates. Mixing of colloidal zeolite solution with aluminogel yielded coagulation of both materials. The mass of zeolite adsorbed by aluminogel increased with decreasing pH. After calcination, pellets of the composite material at zeolite loading below 60 wt % contained separated nanocrystals of 10−15-nm zeolite β stabilized in the mesopores of alumina matrix. The imbedded zeolite had high structure order and acidity. No blocking of the zeolite micropores in composite materials was detected. The activity of zeolite β nanocrystals (imbedded in alumina matrix) in cumene cracking twice that of bulk nanozeolite clusters.