Abstract
A one-pot two-stage synthesis method was developed to synthesize hierarchical nano-sized zeolite beta. The two-stage included the generation of nano-sized zeolite beta precursor and the self-assembly of the zeolite beta precursor around structure directing agent, hexadecyl trimethyl ammonium bromide. The influence of the hydrothermal synthesis time and pH value of the zeolite beta precursors, hydrothermal treatment duration, SDA concentration, and water content during nano-sized zeolite beta precursor self-assembly on the properties of final solid products were studied. The samples were characterized by nitrogen adsorption (BET), NH3-TPD, X-ray powder diffraction, solid state-NMR, and TEM. With the present synthesis method and conditions, compared with the conventional nano-sized zeolite beta synthesis, a longer zeolite precursor crystallization time was required for the successful transformation of the amorphous aluminosilicates precursors into crystalline beta assemblies with hierarchical structure. The further crystallization of zeolite beta precursors during the precursor assembly did not occur under studied pH range, hydrothermal treatment duration, SDA concentration, and water content.