【摘要】 采用NH3－TPD和吡啶吸附红外光谱法，研究了不同含Zn量ZnHZSM-5沸石中Zn的存在状态．结果表明，用浸渍方式将Zn引入到HZSM-5沸石后，在NH3－TPD谱上产生两个新的NH3脱附峰．峰位分别在原HZSM－5沸石的低温峰与高温峰之间和比高温峰较高温区处，其相应的吸附中心分别以L1、L2表示．L1可能与ZnHZSM－5沸石上ZnO物种相对应;L2与吡啶吸附红外光谱的L1616吸收带有关，可能与ZnHZSM-5上的ZnOH＋物种相对应．丙烷芳构化反应结果表明，芳烃收率随L2的脱附NH3量的增加有一最宜值，而活性的稳定性则随之降低。更多还原

【Abstract】 NH3-TPD and pyridine adsorption IR spectroscopy techniques have been used to study the zinc states in ZnHZSM-5 zeolite containing various zine content. The results indicate that, in addition to two desorption peaks for HZSM-5 zeolite located at about 533 and 733K, two new peaks located at about 573 and 873 K were observed. These new peaks are believed to be associated with two kinds of zinc sites designated by L1,L2 .The adsorbed ammonia amount of L2 corresponds to the amount of L1616 acid characterized by pyridine adsorption IR spectra for ZnHZSM-5 zeolite with various zinc contents.It is possible that there are two kinds of zinc states in ZnHZSM-5 zeo lite. One kind of them is ZnO species with weak acidity, the other is ZnOH+ species with strong acidity which can promote the activity and has an effect on stability of activity for aromatization of propane.更多还原