Synthesis of b-axis oriented high silica MFI type zeolite crystals introduced with co-template role

High silica MFI type zeolite crystals with b-axis orientation were hydrothermally synthesized in n-propylamine (R1) · N-ethyl-hexamethylenetetra-ammonium (R2) · Na2O · SiO2 · H2SO4 · NaF · H2O reactant system. XRD, SEM, and 13C CP MAS NMR were used to characterize the morphology, the index of crystallographic preferred orientation (CPO), and the template role of R1 and R2. The compositions of the reactant especially the ratio of R1/R2, which influence the CPO of the obtained zeolite crystals, were investigated in detail. The co-template role for inducing the formation and the growth of b-axis oriented zeolite crystals is discussed.