Seed-assisted synthesis and characterization of nano and micron ZSM-5 molecular sieves in template-free system

A novel and environment friendly seed-assisted one-step and segmented methods were employed to synthesize micro-scale, submicron-scale and nano-scale ZSM-5 molecular sieves in template-free system. The products were characterized by XRD, SEM, FT-IR, TGA/DTA and N2 adsorption-desorption analysis, respectively. The results showed that micro-scale ZSM-5 were prepared by one-step method via ZSM-5 seeds with uniform and regular pupal-like shape and particles size of 5 ​× ​3 ​μm, submicron-scale ZSM-5 of 250~500 ​nm and nano-scale ZSM-5 of 25~40 ​nm were successfully obtained with stacking mesopores via silicate-1 seeds by one-step crystallization method and segmented crystallization method, respectively. Furthermore, the crystallization time could be shortened to 6 ​h by silicate-1 seeds assisted low-high temperature segmented method.