Iridium pair sites anchored to Zr6O8 nodes of the metal–organic framework UiO-66 catalyze ethylene hydrogenation
Journal Article
·
· Journal of Catalysis
- Univ. of California, Davis, CA (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
Isolated metal pair sites on metal oxide and zeolite supports are drawing attention as catalysts, because—in contrast to single atomically dispersed metals—they provide neighboring metal centers that can act cooperatively. We now report pairs of iridium atoms anchored to the Zr6O8 nodes of the metal–organic framework (MOF) UiO-66, synthesized by chemisorption of Ir2(μ-OCH3)2(COD)2 (COD is cyclooctadienyl) followed by removal of the COD ligands. The supported species were characterized with infrared spectra of adsorbed CO combined with iridium LIII-edge extended X-ray absorption fine structure and high-energy-resolution fluorescence detection X-ray absorption near edge (HERFD XANES) spectra. The HERFD XANES spectra were recorded with the sample in a variety of atmospheres in which the iridium pair sites were stable, including CO, H2, and C2H4 + H2 at temperatures in the range of 35–80 °C. The data provide sensitive measures of the electronic structure of the iridium in the pair sites. The samples were evaluated as catalysts for ethylene hydrogenation, with the pair-sites being more selective for hydrogenation than analogous isolated atomically dispersed iridium, which catalyzes both hydrogenation and isomerization. Metal pair sites on MOFs offer uncharted opportunities for catalysts having reactivities associated with neighboring metal centers.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research Center for Inorganometallic Catalyst Design (ICDC); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-76SF00515; SC0012702
- OSTI ID:
- 1876091
- Alternate ID(s):
- OSTI ID: 1961428
- Journal Information:
- Journal of Catalysis, Journal Name: Journal of Catalysis Vol. 411; ISSN 0021-9517
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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