(669a) Single-Site Iridium Complexes on MgO Powder:  Spectroscopic, Microscopic, and Catalytic Evidence of Dependence of Properties on MgO Surface Sites

Hoffman, A., Villanova University
Debefve, L., University of California, Davis
Zhang, S., University of Alabama
Dixon, D. A., University of Alabama
Gates, B. C., University of California at Davis
Supports for Metal Catalysts Are Often High-Area Metal Oxides That Present Highly Nonuniform Surface Sites for Bonding of Metals. in Attempts to Understand How Specific Support Surface Sites Bond with Metal Cations, We Investigated Single-Site Iridium on Powder MgO Treated to Control the Support Surface Sites, Including Faces and Defect Sites. the Catalysts Were Synthesized from the Precursor Ir(C2H4)2(acetylacetonate), and the MgO Treatment Conditions Were Selected to Generate Various Surface Sites for Bonding of the Iridium. X-Ray Absorption Spectra Characterizing the Supported Iridium Complexes Identify Distinct Irâ??Support Surface Site Contributions on the Various MgO Supports and for Iridium Loadings in the Range of 0.1 to 1.0 Wt%. Probing of the Supported Iridium Species with CO (to form iridium