Zeolites are one of the most important classes of materials for catalysis and technological applications and therefore they are extensively and increasingly studied from different perspectives. However, surface science approaches to study reaction mechanisms in zeolites has remained limited due to the lack of a sample suitable for the analytical techniques used in this field. We have overcome this limitation by using self-containing aluminosilicate ultra-thin films consisting of planar arrays of polygonal prisms which are bound to a metallic substrate only by Van der Waals interactions. In this presentation, an overview of chemical and structural aspects will be given for films with varying Si/Al ratios, in comparison to zeolites. In terms of the chemistry, films with Si/Al ratios between 1 and 3 present highly acidic bridging hydroxyls which, in zeolites, are the active sites for reactions such as the catalytic cracking of crude oil, oligomerization of olefins and conversion of methanol to hydrocarbons. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/239nm/uploads/3287_12006.jpg' alt='' /> The acidity of the active sites was measured by following the frequency shift of the OH vibration upon adsorption of CO and C2H4 as probe molecules. In addition, the latter allowed the determination of the geometry of C2H4 with respect to the bridging OH, which provides information about the precursor state in the ethylene polymerization reaction.

Surface science meets zeolites: Using ultrathin aluminosilicate films as model systems for zeolites

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.