Electronic Structure of Atomically Dispersed Supported Iridium Catalyst Controls Iridium Aggregation

Kurtoğlu, Samira F.; Hoffman, Adam S.; Akgül, Deniz; Babucci, Melike; Aviyente, Viktorya; Gates, Bruce C.; Bare, Simon R.; Uzun, Alper

doi:10.1021/acscatal.0c03909

DOE OSTI · 1769353

Electronic Structure of Atomically Dispersed Supported Iridium Catalyst Controls Iridium Aggregation

Kurtoğlu, Samira F.·Hoffman, Adam S.·Akgül, Deniz·Babucci, Melike·Aviyente, Viktorya·Gates, Bruce C.·Bare, Simon R.·Uzun, Alper

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Abstract

Supported iridium complexes, Ir(C 2 H 4 ) 2 /support, were characterized by X-ray absorption spectroscopy during a temperature ramp to 120 °C in flowing H 2 . Iridium in complexes bonded to weak and moderate electron-donor supports, SiO 2 and γ-Al 2 O 3 , underwent aggregation, forming nanoparticles and clusters, respectively. When the support was a strong electron-donor (MgO), iridium remained site-isolated. Density functional theory calculations confirm the dependence of iridium–support bond strength on the support’s electron-donor character. Coating the SiO 2 -supported complexes with 1-n-ethyl-3-methyl-imidazolium acetate enhanced electron density on the iridium, hindering its aggregation. Finally, these results demonstrate opportunities for stabilizing atomically dispersed supported noble metals under reducing conditions by choice of support/ionic liquid sheath combinations.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY atomically dispersed metal catalyst stability ionic liquid sheath metal aggregation metal sintering single-site metal supported metal

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Kurtoğlu, Samira F., Hoffman, Adam S., Akgül, Deniz, Babucci, Melike, Aviyente, Viktorya, Gates, Bruce C., Bare, Simon R., Uzun, Alper. 2020-10-08. Electronic Structure of Atomically Dispersed Supported Iridium Catalyst Controls Iridium Aggregation. https://doi.org/10.1021/acscatal.0c03909

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