A structural study of the Fe/ZSM-5 catalyst by through-focus exit-wavefunction reconstruction in HRTEM

Abstract: Through-focus exit-wavefunction reconstruction in high-resolution transmission electron microscopy has been applied to process the image series obtained from both the simple ZSM-5 catalyst and an iron-loaded one prepared by impregnation. In conventional high-resolution transmission electron microscopic observations, artificial patches due to electron optical effects always appear in the centers of the ten-member ring channels of the ZSM-5 structures, preventing the atomic details in the channels to be revealed, which are crucial information for understanding the catalytic properties of this type of catalysts. Our study shows that such artificial patches can be removed in the retrieved exit-wavefunctions, allowing the projected structures of the ZSM-5 zeolites to be imaged. Together with X-ray energy dispersive spectroscopy, through-focus exit-wavefunction reconstruction confirmed the existence of iron atoms in the ten-member ring channels of the iron-loaded ZSM-5 catalyst. [Copyright &y& Elsevier]