Controlled Assembly of Nanoporous Materials: Addressing the Voids in our Understanding of Zeolite Crystallization*

The unique properties of nanoporous zeolites find use in a variety of applications spanning ion exchange and separations to catalysis and drug delivery. The ability to selectively control zeolite synthesis to achieve desired physicochemical properties relies upon detailed understandings of the thermodynamic and kinetic factors regulating crystal nucleation and growth, which are generally lacking. Designing innovative approaches to tailor zeolite crystallization and exploit unique structure-performance relationships has the potential to produce materials with superior properties beyond what is achievable by conventional routes. In this talk, I will discuss efforts to elucidate the complex mechanisms of zeolite crystallization, which occur by nonclassical pathways [1] involving the self-assembly and structural evolution of amorphous precursors. There is still much that we do not understood regarding the role of precursors in nucleation and the influence of growth conditions on the selection of crystal topology, which underscores the need for molecular-level studies of zeolite crystallization. Our group addresses these challenges using a broad range of techniques that include the use solvothermal atomic force microscopy to capture time-resolved images of growing zeolite surfaces in real time.[2] This technique has led to the first in situ characterization of zeolite growth with the capability of resolving surface dynamics at the spatiotemporal scales necessary to elucidate mechanistic pathways of crystallization. Based on our findings, we observe that growth occurs via multiple (cooperative) pathways that differ from one material to the next. In this talk, we will summarize our findings for several zeolite structures.

1. De Yoreo, J. J. et al., Science 2015, 349 (6247), 498-+.
2. Lupulescu, A. I.; Rimer, J. D., Science 2014, 344 (6185), 729-732.