Journal of Inorganic Materials ›› 2018, Vol. 33 ›› Issue (1): 27-34.DOI: 10.15541/jim20170141

• Orginal Article • Previous Articles     Next Articles

Hierarchical Beta Zeolite Prepared by Steam-assisted Conversion Method

SUN Xiao-Bo1, DU Yan-Ze1,2, QIN Bo2, KONG Qing-Lan1, WU Liang1, ZHENG Jia-Jun1, PAN Meng1, LI Rui-Feng1   

  1. 1. Research Center of Energy Chemical & Catalytic Technology, Taiyuan University of Technology, Taiyuan 030024, China;;
    2. Fushun Research Institute of Petroleum and Petrochemicals, SINOPEC, Fushun 113001, China
  • Received:2017-03-28 Revised:2017-05-08 Published:2018-01-23 Online:2017-12-15
  • Supported by:
    Joint Funds of the National Natural Science Foundation of China-China Petroleum and Chemical Corporation (U1463209);National Natural Science Foundation of China (21371129, 21376157);SINOPEC (116050)

Abstract:

Synthesis of hierarchical zeolite with complex micropore-mesopore structures has attracted great attention because of their practical or potential applications. In present study, hierarchical Beta zeolite was synthesized by the “steam-assisted conversion (SAC)” method without secondary template. Factors affecting formation of the hierarchical Beta, such as the added amount of organic template, alkalinity and silica to alumina ratio of the gel precursors yielding the hierarchical Beta zeolite, vapor pressure and crystallization time during the “steam-assisted conversion (SAC)” process, were investigated. The structural, crystalline and textural properties of the as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscope, Raman spectrum, N2 adsorption-desorption, and NH3-TPD. The formation mechanism of the hierarchical Beta was explored on the base of the results detected by FT-IR, Raman spectrum, and SEM. Results showed that the as-synthesized Beta zeolite was composed of primary nano-sized crystals with a diameter of 10-40 nm, and a mesoporous structure ranging from 2 to 30 nm was therefore introduced. A tremendous amount of primary and/or subprime building units, which were bred during preparation of dry gel, induced a burst in nucleation rate. Nano-sized zeolite crystals were, therefore, created that subsequently formed polycrystalline Beta zeolite material by aggregating the nanocrsytals with each other.

Key words: hierarchical pore, Beta zeolite, “steam-assisted conversion” method

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