April 12, 2021

Abstract – The diverse network of confined pores in zeolites have been widely used for shape-selective catalysis in the (petro)chemical industry. A common objective of zeolite catalyst design is to overcome the inherent mass transport limitations of nanopores; however, the complex pathways of zeolite crystallization make it difficult to control their physicochemical properties.^1-2

In this talk, I will highlight several methods to tailor zeolite crystal size, morphology, and composition in ways that collectively reduce diffusion limitations, thereby enabling the design of catalysts with superior performance compared to materials obtained by conventional synthesis routes. We have discovered new methods to generate 2-dimensional (single layer) zeolites with high external surface area,³ while also developing methods to passivate external sites via epitaxial growth of coreshells. We will demonstrate how a combination of these two techniques allows for the deconstruction of zeolites with distinct topological features to elucidate the origins of improved catalyst performance (i.e. selectivity and lifetime). Our findings also reveal that coreshell (or zoned) zeolites with Si-rich exterior surfaces can dramatically reduce diffusion limitations, thereby resulting in catalysts that are far superior to analogues with homogeneous distributions of acid sites. As additional examples of zeolite crystal engineering, we will describe structure-performance relationships of various hierarchical materials, such as self-pillared pentasils that exhibit four-fold increases in both lifetime and total turnovers. Lastly, we will introduce a new class of catalysts, referred to as finned zeolites,⁴ which are prepared by seeded growth to introduce fin-like protrusions (size α) with identical crystallographic registry as the interior crystal (size β). Examples of both 2- and 3-dimensional zeolites will be discussed using methanol to hydrocarbons (MTH) as benchmark reaction and state-of-the-art characterization using techniques such as high-resolution electron tomography, operando spectroscopy, novel acid titration methods, and molecular modeling to correlate structural features of finned zeolites and their diffusion properties with enhanced catalyst performance.

References

1. Choudhary, M. K.; Jain, R.; Rimer, J. D., In situ imaging of two-dimensional surface growth reveals the prevalence and role of defects in zeolite crystallization. Proc. Natl. Acad. Sci. U. S. A. 2020, 117 (46), 28632-28639.
2. Lupulescu, A. I.; Rimer, J. D., In Situ Imaging of Silicalite-1 Surface Growth Reveals the Mechanism
   of Crystallization. Science 2014, 344 (6185), 729-732.
3. Zhou, Y. W.; Mu, Y. Y.; Hsieh, M. F.; Kabius, B.; Pacheco, C.; Bator, C.; Rioux, R. M.; Rimer, J. D.,
   Enhanced Surface Activity of MWW Zeolite Nanosheets Prepared via a One-Step Synthesis. J. Am.
   Chem. Soc. 2020, 142 (18), 8211-8222.
4. Dai, H.; Shen, Y. F.; Yang, T. M.; Lee, C. S.; Fu, D. L.; Agarwal, A.; Le, T. T.; Tsapatsis, M.; Palmer,
   J. C.; Weckhuysen, B. M.; Dauenhauer, P. J.; Zou, X. D.; Rimer, J. D., Finned zeolite catalysts. Nat.
   Mater. 2020, 19 (10), 1074-+.

Biography – Jeffrey Rimer is the Abraham E. Dukler Endowed Chair and Professor of Chemical Engineering at the University of Houston. Jeff received B.S. degrees in Chemical Engineering and Chemistry from Washington University in St. Louis and Allegheny College, respectively. He received his Ph.D. in Chemical Engineering from the University of Delaware and spent two years as a postdoctoral fellow at New York University prior to joining Houston in 2009. Jeff’s research in the area of crystal engineering focuses on the rational design of materials with specific applications in the synthesis of microporous catalysts and adsorbents, and the development of therapeutics to inhibit crystal formation in pathological diseases. Jeff has received numerous awards that include the NSF CAREER Award, the 2016 Owens Corning Early Career Award and 2017 FRI/John G. Kunesh Award from AIChE, and the inaugural 2016 Mellichamp Emerging Leader Lecturer at the University of California at Santa Barbara. In 2018 he received the Norman Hackerman Award in Chemical Research from The Welch Foundation, and in 2020 the Edith and Peter O’Donnell Award in Engineering from TAMEST. He has also been the recipient of the Excellence in Research and Scholarship Award from the University of Houston, and Teaching Excellence Awards at both the University and College level. Jeff is a former chair of the Southwest Catalysis Society, an executive committee member for the American Associate for Crystal Growth and International Zeolite Association, and has chaired two Gordon Research Conferences on Crystal Growth & Assembly and Nanoporous Materials & Their Applications. He is an Associate Editor of ACS Crystal Growth & Design and also serves on the advisory boards for the AIChE Journal, Molecular Systems Design & Engineering, and Reaction Chemistry & Engineering.