(196d) First-Principles Investigation of Cu Ion Exchange and Siting Preference in FER Zeolite

Authors: 
Zhao, Z., University of Notre Dame
Li, S., University of Notre Dame
Schneider, W. F., University of Notre Dame
Wang, Y., University of Notre Dame
Gounder, R., Purdue University
Prasad, S., BASF Corporation
Moini, A., BASF Catalysts LLC
Jones, C., Purdue University
DeBellis, A., BASF Corporation
Di Iorio, J. R., Purdue University
Cu-exchanged zeolites, in particular Cu-SSZ-13, are known to be active materials for the selective catalytic reduction (SCR) of NOx with NH3. SCR activity is known to be associated with isolated, exchanged Cu ions, and thus the nature of Cu exchange is critical in understanding the relationship between catalytic activity and framework topology, Si:Al ratio, and co-cations. In SSZ-13, it is now well established that Cu2+ exchanges into the framework at proximal pairs of charge-compensating framework Al within a six-membered ring (6MR) to create Z2Cu sites and at isolated framework Al to form ZCu2+OH sites. Construction of the composition phase diagram for SSZ-13 is facilitated by the high symmetry of the CHA lattice.

In this work, we explore extending this methodology to lower symmetry frameworks, with a particular emphasis on FER, chosen because FER is a 2-dimensional framework with multiple T-sites. We interrogate and compare Cu exchange in zeolites through first-principle simulations and statistical enumeration. We identify the sensitivity of the Cu speciation and siting preference to zeolite topology, which promises the potential of rational choice of zeolite topology to tailor the Cu speciation.This approach can be extended to calculate the Cu speciation of other zeolite topologies for specific catalytic applications of interest.