Infrared and temperature-programmed desorption study of the acidic properties of ZSM-5-type zeolites
Infrared and temperature-programmed desorption study of the acidic properties of ZSM-5-type zeolites
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DOI：
10.1016/0021-9517(81)90315-8
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发表时间：
1981-07
影响因子：
7.3
通讯作者：
N. Topsoe;K. Pedersen;E. Derouane
中科院分区：
文献类型：
--
作者：
N. Topsoe;K. Pedersen;E. Derouane
用红外光谱和程序升温脱附法研究了ZSM-5型沸石的酸性。活性酸位的浓度与铝含量有关，最有可能位于通道交叉点，其特征在于在3600 cm-1处的红外带和773 K附近的解吸峰（γ态）。较弱的酸性位点的特征是在3720-3740 cm− 1处的红外带和在约500 K处的解吸峰（β态）。它们可能对应于沸石外表面上的末端硅烷醇基团或可能的非沸石杂质。刘易斯酸中心也具有γ-态脱附峰，而Na吸附中心对氨的脱附峰也具有β-态脱附峰。吡啶脱附有助于沸石的脱羟基。
Infrared spectroscopy and temperature-programmed desorption have been used to investigate the acidic properties of ZSM-5-type zeolites. Active acidic sites, in concentration related to the aluminum content and most probably located at the channel intersections, are characterized by an ir band at 3600 cm−1and a desorption peak near 773 K (γ state). Weaker acidic sites are characterized by an ir band at 3720–3740 cm−1and a desorption peak at about 500 K (β state). They probably correspond to terminal silanol groups on the external surface of the zeolite or possibly nonzeolitic impurities. Lewis acidic sites are also characterized by the γ-state desorption peak, while Na adsorption centers for ammonia give rise to a β-state peak. Pyridine desorption helps dehydroxylation of the zeolite.