Characterization of Acidic OH Groups in Y-Type Zeolites by Means of Different Methods of Temperature-Programmed Desorption (TPD) of Ammonia

被引:2
|
作者
Annette Trunschke
Bernd Hunger
机构
[1] Institute for Applied Chemistry Berlin-Adlershof,Wilhelm
[2] University of Leipzig,Ostwald
来源
Topics in Catalysis | 2002年 / 19卷
关键词
NH; -TPD; FTIR-TPD; HNaY zeolites with different proton content; OH groups; effective desorption energy; acid strength distribution; adsorption states of ammonia;
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摘要
The acidic properties of HNaY zeolites with different degrees of exchange have been studied by means of two complementary techniques of temperature-programmed desorption (TPD) of ammonia, namely, FTIR-TPD and conventional TPD. In HNaY zeolites with low exchange levels only a single type of OH group is observed. The analysis of the spectra in the region of NH bending modes during NH3-FTIR-TPD on zeolites with higher proton content (40% or higher) shows that ammonia is bound in two different adsorption states. This assessment is further confirmed by evaluation of the OH stretching region. Furthermore, desorption energy distribution functions for the different types of OH groups have been calculated using a numerical regularization method.
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页码:215 / 223
页数:8
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