(152a) Role of Surface Acidity on Immobilization and Stability of Rhodium Complexes on Zsm-5: In Situ FTIR, Raman, and Xas Characterization

The anchoring of organometallic complexes with simple structures on zeolites provides an opportunity to investigate well-defined active metal centers in heterogeneous catalysts. The goal of this research was to investigate the surface chemistry during the reaction of three well-defined rhodium precursors (Rh^I(CO)₂(acac), Rh₂^II(O₂CCH₃)₄, or Rh^III(acac); (acac is acetylacetonate, C₅H₇O₂)) and ZSM-5 with different Si/Al ratios (23, 50, and 280) and the formation of their corresponding well-defined active rhodium centers by using an ensemble of in-situ spectroscopic techniques. The samples were characterized by XRD and TEM before and after the immobilization of the rhodium centers. In situ characterization of the samples was performed by FTIR, Raman, and XAS during different temperature and flow treatments to determine the structure and stability of the initial rhodium centers. A discussion on the influence of the zeolite Si/Al ratio on the immobilization and stability of the rhodium precursors will be presented.