TRACKING ATOMIC SCALE STRUCTURAL CHANGES IN SUPPORTED MOLECULAR METAL CATALYSTS BY SPECTROSCOPY AND MICROSCOPY

摘要

Almost all the reported molecular-scale characterizations of supported catalysts have been obtained indirectly by spectroscopic methods. Local structural information at this scale has been lacking because imaging of supported metal species (including extremely beam-sensitive zeolites as supports) by (scanning) transmission electron microscopy (S/TEM) has been limited by electron-beam damage. However, recent results have shown that supported metal catalysts with essentially molecular structures can now be characterized at the atomic level by aberration-corrected scanning transmission electron microscopy (ACSTEM) used in conjunction with infrared and X-Ray absorption spectroscopies. By rapid sequential image acquisition, the influence of electron beam can now be turned into an advantage, and transformations of supported species can be followed with atomic resolution.