水蒸气处理对HZSM-5分子筛催化剂的酸性及孔结构的影响
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摘要: 通过XRD，NH3-TPD，IR，比表面与孔结构测定等方法，研究了HZSM-5分子筛（硅铝比为38）在不同温度下进行水热处理时的酸性与孔结构。结果表明，随着水热处理温度的提高，HZSM-5分子筛的结晶度稍有增大；酸性明显减弱，弱酸位增多，强酸位相对减少；IR谱图上有一定的蓝移；比表面与微孔体积减小，介孔体积增大。Abstract: The acidity and texture of HZSM-5 zeolites (ratio of silica-to-alumina is 38) treated with steam at different temperatures were studied by XRD, NH3-TPD, IR, specific surface area and pore texture determination. The results show that the crystallinity of HZSM-5 zeolites reduces slightly with the increase of treating temperature. NH3-TPD reveals that the acidity decreases remarkably after steam treatment. The weak acid sites increases, while the strong acid sites decreases relatively with the increase of temperature. A definite blue shift in IR wave number was observed when the sample was hydrothermally treated at different temperatures. The surface area and microporous volume decrease, while mesoporous volume increases.
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Key words:
- steam treatment /
- ZSM-5 /
- surface area /
- acidity /
- pore texture
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