Simple Synthesis of Pore Highways Inside of Catalysts

House-of-Cards structure leads to improved zeolite catalyst.

Sheets of zeolite catalysts form an open pore structure like a “house-of-cards” — Image courtesy of Dawn Adin and John Buchner

The Science

Repetitive branching, a novel and simple synthesis method, produces crystals of zeolite, an important industrial chemical, with large-pore “highways” that improve transport and utilization of chemicals within the crystal.

The Impact

Zeolite catalysts have many applications in petrochemicals, pharmaceuticals, biomass, and water purification. This synthesis method improves the effectiveness of traditional zeolites with no increase in cost or unwanted change in functionality.

Summary

Increasing demand for energy and materials has led to an accelerated research effort in the development of renewable chemicals for a sustainable economy. Efforts within the Catalysis Center for Energy Innovation (CCEI), a DOE-funded Energy Frontier Research Center (EFRC), are aimed at realizing novel catalytic processes for production of chemicals and fuels from biomass-derived feedstocks by bridging catalyst design, reaction engineering and fundamental understanding of reaction mechanism. The researchers used a novel and simple synthesis technique, called repetitive branching, to stack the thin zeolite sheets at right angles generating a "house-of-cards" shaped crystal. By creating zeolite crystals with large-pore "highways," which are about 10 times bigger than the zeolite pores, chemicals and molecules can pass rapidly through the channels to reach the smaller, reactive pores within the crystal. This results in faster, more selective, and more stable catalysts, produced at the same cost as traditional zeolite catalysts. Research was performed at the University of Minnesota and has been licensed to Argilex.

Contact

Michael Tsapatsis
University of Minnesota
tsapatsis@umn.edu

Dion Vlachos
Director of the Catalysis Center for Energy Innovation EFRC
vlachos@udel.edu

Funding

DOE Office of Science Basic Energy Sciences program, Energy Frontier Research Centers (EFRC) program (all aspects of self-pillared pentasil zeolite); Abu Dhabi-Minnesota Institute for Research Excellence (partial support for synthesis and catalytic testing of comparison zeolites); National Science Foundation (partial support for synthesis and catalytic testing of comparison zeolites); University of Minnesota Institute on the Environment—Initiative for Renewable Energy and the Environment (partial support for synthesis and catalytic testing of comparison zeolites); University of Minnesota Characterization Facility partially supported by NSF; Minnesota Supercomputing Institute (computing resources); University of Minnesota Graduate School doctoral dissertation fellowship (X.Z.); ADGAS and GASCO (Y.A.W.).

Publications

Zhang, X. Y. et al. “Synthesis of Self-Pillared Zeolite Nanosheets by Repetitive Branching” Science 336 1684-1687 (2012). [DOI: 10.1126/science.1221111]

Varoon, K, et al. "Dispersible exfoliated zeolite nanosheets and their application as a selective membrane." Science 334 72-75 (2011). [DOI: 10.1126/science.1208891]