Preparation and characterization of nanosized silicalite-2 zeolites by steam-assisted dry gel conversion method
Preparation and characterization of nanosized silicalite-2 zeolites by steam-assisted dry gel conversion method
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DOI：
10.1016/j.matlet.2013.03.051
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发表时间：
2013-06
影响因子：
3
通讯作者：
Yue Cheng;S. Pan
中科院分区：
文献类型：
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作者：
Yue Cheng;S. Pan
以四丁基氢氧化铵(TBAOH)为结构导向剂，正硅酸乙酯(TEOS)为硅源，采用水蒸气辅助干凝胶转化技术成功合成了纳米Silicalite-2沸石。用X射线衍射仪(XRD)、傅里叶变换红外光谱(FTIR)、氮气吸附与脱附(BET)和场发射扫描电子显微镜(FESEM)对产物进行了表征。X-射线衍射图证实了在170℃下晶化48h得到的Silicalite-2，样品的衍射线随着TBAOH含量的增加而变宽。FESEM分析表明，所合成的Silicalite-2纳米晶颗粒大小约为70-90 nm。氮气的吸附和解吸提供了明显的证据，表明孔洞可以从沸石晶体的外表面完全接触到。在551.5和1229.2 cm−1附近的振动带表明分子筛结构中存在双5环，550 cm−1/460 cm−1带强度比的值表明沸石的结晶度接近100%。
Nanosized silicalite-2 zeolite was successfully synthesized by steam-assisted dry-gel conversion technique with TBAOH (tetrabutylammonium hydroxide) as structure directing agent and TEOS (tetraethoxysilane) as silica source. The products were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, N2adsorption and desorption (BET) and Field emission scanning electron microscopy (FESEM). XRD pattern confirmed the crystallization of silicalite-2 obtained at 170°C for 48h, the diffraction lines of samples were broadened as a result of the decreased in particle size with the content of TBAOH increased. FESEM images showed that the silicalite-2 nanocrystals with a particle size of about 70–90nm. N2adsorption and desorption provides manifest evidence that the porosity is fully accessible from the external surface of the zeolite crystal. The vibration bands at around 551.5 and 1229.2cm−1indicated the presence of double 5-ring in the pentasil zeolite structure of MEL, values of the 550cm−1/460cm−1band intensity ratios demonstrated that the crystallinity of zeolite closed to 100%.