Relating Pore Structure to Activity at the Subcrystal Level for ZSM-5: An Electron Backscattering Diffraction and Fluorescence Microscopy Study

Abstract

The catalytic performance of microporous materials such as zeolites is determined not only by the active sites' molecular architecture, but also by the organization of the surrounding pores with varying diameter, shape, and directionality. These pores control transport of reagents and products and induce shape selectivity. Rather than being ideal single crystals, zeolites often have complex 3-dimensional morphologies, comprising intergrowths and various defect types. Here, the underlying pore architecture of the hexagonal facet of an individual zeolite ZSM-5 crystal is successfully determined by electron beam scattering diffraction and is correlated with the initial reactivity toward the acid-catalyzed oligomerization of furfuryl alcohol using polarized fluorescence microscopy.