Progress in electron energy loss spectroscopy of Cu-ZSM-5 zeolite

Abstract

The copper containing zeolite Cu-ZSM-5 recently has attracted worldwide attention due to its ability to decompose nitrogen oxides (NOx) , an undesirable constituent of vehicle exhaust. Faced with the problem of NOx control in lean burn engines designed to improve fuel economy, this zeolite is thought to hold the promise of more efficient catalytic converters for NOx. An effort was therefore made to characterize this material with a JEOL-2000FXII analytical electron microscope.Fine powder samples of Cu-ZSM-5 and H-ZSM-5 were acquired from a vendor and analyzed in a comparative study. The AEM specimens were made either by placing a droplet of a fine powder suspension on a carbon coated grid, or by microtoming a resin embedded block of the zeolite and collecting thin sections on a grid. Fig. 1 is a high resolution micrograph taken in the channel direction (the b-axis) of the zeolite crystalline structure along with the diffraction pattern from the same area (Fig. 2). Both Cu-ZSM-5 and H-ZSM-5 samples showed the same structure images in all lattice orientations. These results are consistent with the published x-ray diffraction data on the ZSM-5 zeolite lattice structure.