ADVANCED MICROSCOPY FOR MESOPOROUS ZEOLITE CHARACTERIZATION: INTER- AND INTRAPARTICLE HETEROGENEITY

摘要

The performance of zeolites as solid acid catalysts is largely determined by an intricate interplay between acid site strength, distribution and accessibility. As such, structural variations within and between particles potentially have an important impact on the performance, since synthetic zeolites commonly grow as complex aggregates of small nanocrystallites. Furthermore, post-synthetic modifications, routinely applied to enhance catalyst performance, add to this heterogeneity: besides acid leaching or hydrothermal treatments, which increase active site accessibility, ion exchange procedures can be applied to introduce rare-earths into the microporous structure to increase acidity and stability.