3 years ago

TNU-9 Zeolite: Aluminum Distribution and Extra-Framework Sites of Divalent Cations

TNU-9 Zeolite: Aluminum Distribution and Extra-Framework Sites of Divalent Cations
Petr Sazama, Petr Klein, Haunani M. Thomas, Jiri Dedecek, Robert Karcz, Stepan Sklenak, Edyta Tabor, Barbara Supronowicz, Veronika Pashkova
The TNU-9 zeolite (TUN framework) is one of the most complex zeolites known. It represents a highly promising matrix for both acid and redox catalytic reactions. We present here a newly developed approach involving the use of 29Si and 27Al (3Q) MAS NMR spectroscopy, CoII as probes monitored by UV/Vis and FTIR spectroscopy, and extensive periodic DFT calculations, including molecular dynamics, to investigating the aluminum distribution in the TUN framework and the location of aluminum pairs and divalent cations in extra-framework cationic positions. Our study reveals that 40 and 60 % of aluminum atoms in the TNU-9 zeolite are isolated single aluminum atoms and aluminum pairs, respectively. The aluminum pairs are present in two types of six-membered rings forming the corresponding α and β (15 and 85 %, respectively, of aluminum pairs) sites of bare divalent cations. The α site is located on the TUN straight channel wall and it connects two channel intersections. The suggested near-planar β site is present at the channel intersection. Location, location! A newly developed approach for investigating the aluminum distribution in the TUN framework of the TNU-9 zeolite and for studying the location of aluminum pairs and divalent cations in extra-framework cationic positions is presented. The α (blue) and β (red) cationic sites of bare divalent cations are suggested (see figure).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201605685

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.