Direct Synthesis of Nano-crystalline HZSM-5 Zeolite via Varying-temperature Hydrothermal Synthesis

摘要

A nano-crystalline HZSM-5 zeolite was directly synthesized by two-stage varying-temperature synthesis method. The effects of second stage time and temperature on the particle size and morphology were of interest. The morphology of particles were specified by scanning electronic microscopy (SEM) and crystallinity of the samples were recorded by X-ray diffraction (XRD) test results. It was observed that second stage time had a strong effect on crystallinity and morphology; highly crystalline ZSM-5 zeolite with twinned crystals was synthesised at 180°C, 60 h (second stage time and temperature). The HZSM-5 particles synthesised at 180°C, 18 h (second stage time and temperature)were 300-600 nm in size and constructed by primary HZSM-5 nanocrystals of 20～30 nm.