(36d) Influence of Al-Al Proximity on Metal Ion Exchange in SSZ-13 Zeolite and Strategies to Characterize and Control It

Influence
of Al-Al Proximity on Metal Ion
Exchange in SSZ-13 Zeolite and Strategies to Characterize and Control it

Sichi
Li¹, Claire T. Nimlos², Casey Jones², Anthony
Debellis³, Imke
Britta Mueller⁴, Subramanian Prasad⁵, Ahmad Moini⁵, Rajamani Gounder² and William F. Schneider¹

1 Department of Chemical and Biomolecular Engineering, University of
Notre Dame, Notre Dame IN 46556 (USA)

2 Davidson School of
Chemical Engineering, Purdue University, West Lafayette, IN 77907 (USA)

3 BASF Corporation, 540 White Plains Road, Tarrytown, New York 10591
(USA)

4 BASF SE, 67056 Ludwigshafen
(Germany)

5 BASF Corporation, 25
Middlesex Essex Turnpike, Iselin, NJ 08830 (USA)

The Al distribution in a given zeolite is generally
a fixed tableau upon which ions exchange, at least under mild conditions under
which aluminum migration and dealumination do not occur. Catalytic activity is
often associated with extra-lattice ions associated with the Al centers, and
thus an understanding of the chemistry of ion exchange is an important
prerequisite to understanding catalytic function. Further, knowledge of ion
exchange may point towards chemical probes that may be useful as titrants for
specific combinations of Al.

In this work we summarize the insights obtained
from computations on Cu²⁺ [1] and Fe^2+/3+ [2] ion exchange,
relate these results to experimental observations, and expand upon the prior
work by reporting complete computational databases for relative exchange
energies of the family of alkaline earths (Mg, Ca, Sr, and Ba) and the 3d
transition metals (Mn, Fe, Co, Ni, Cu, and Zn), using supercell density
functional theory (DFT). We identify common and discriminating features, in
particular features that may be exploited to selectively interrogate different
Al arrangements through chemical titrations. We further explored sensitivity of
these results to co-adsorption of H₂O and to competition between
charge compensation by two framework Al and charge compensation by single Al
and extra-lattice OH^-. Lastly,
we report computations of structures associated with as-synthesized phase, that
provide guidance on controlling Al proximity during
zeolite synthesis. The results here collectively illustrate the power of
first-principles modeling in zeolite research that can shed light on various
aspects in the life cycle of zeolite materials.

References:

1. Li, S., Li, H., Gounder,
R., Debellis, A., Mueller, I. B., Prasad, S., Moini, A. and Schneider, W. F. J. Phys. Chem. C 122, 41, 23564 (2018).

2. Li, S., Wang, Y., Wu, T. and Schneider, W. F. ACS Catal. 8,
11, 10119 (2018).