740d Nanoscale Catalytic Materials by Swelling, Pillaring and Exfoliation of a Zeolite Precursor

Sudeep Maheshwari¹, Edgar Jordan², Sandeep Kumar¹, Frank S. Bates¹, R. Lee Penn³, Daniel F. Shantz², and Michael Tsapatsis¹. (1) Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455, (2) Department of Chemical Engineering, Texas A&M University, College Station, TX 77843, (3) Department of Chemistry, University of Minnesota, 207 Pleasant St SE, Minneapolis, MN 55455

The zeolite MCM-22 is formed by calcination of a layered precursor, MCM-22(P)[1]. The layered structure of the precursor allows swelling, pillaring and exfoliation to single layers to produce a host of nanomaterials[2,3]. However, these procedures result in significant degradation of the structure of the layers with partial loss of crystallinity[4,5]. In this work, we describe a modified approach to swell, pillar and exfoliate the MCM-22 layered precursor with improved preservation of crystal morphology and alumino-silicate layer structure. XRD reveals that the swollen derivative evolves to a new ordered layer structure upon washing with water. Solid state NMR spectroscopy indicates preservation of framework connectivity. This ordered material can act as starting material to form inorganic/organic hybrid catalysts with specific guest-host interactions. Interestingly, the swollen derivative can be restored back to the precursor structure by acidification. It can be successfully pillared to produce an MCM-36[2] analogue or exfoliated to produce a high surface area material analogous to ITQ-2[3] but with improved crystallinity. The resulting materials are expected to exhibit distinct catalytic behavior compared to the pre-existing analogues, due to the improved preservation of the pore structure and catalytic sites.

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[2] Kresge, C. T.; Roth, W. J., US Patent 5278115, 1994.

[3] Corma, A.; Fornes, V.; Pergher, S. B.; Maesen, T. L. M.; Buglass, J. G., Nature, 1998, 396, 353-356.

[4] Schenkel, R.; Barth, J. O.; Kornatowski, J.; Lercher, J. A., Studies in Surface Science and Catalysis, 2002, 142A, 69-76.

[5] Wu, P.; Nuntasri, D.; Ruan, J.; Liu, Y.; He, M.; Fan, W.; Terasaki, O.; Tatsumi, T., Journal of Physical Chemistry B, 2004, 108, 19126-19131.