A Diffuse Reflectance Infrared Fourier-Transform Spectra and Density Functional Theory Study of CO Adsorption on Rh/-Al2O3

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• 作者：Constantinos D. Zeinalipour-Yazdi ; Andrew L. Cooksy ; Angelos M. Efstathiou
• 刊名：Journal of Physical Chemistry C
• 出版年：2007
• 出版时间：September 20, 2007
• 年：2007
• 卷：111
• 期：37
• 页码：13872 - 13878
• 全文大小：273K
• 年卷期：v.111,no.37(September 20, 2007)
• ISSN：1932-7455

文摘

The vibrational frequencies and bond dissociation energies of carbon monoxide adsorbed to various rhodiumclusters are computed, and the diffuse reflectance infrared Fourier-transform (DRIFT) spectrum of carbonmonoxide adsorbed onto Rh/-Al₂O₃ is reported. The computations reveal that the spectral features that havepreviously been assigned to symmetric and antisymmetric vibrational modes of isolated dicarbonyl specieson Rh can also be assigned to vibrational coupling of adjacent linearly bound carbonyl groups (atop M-CO).We explore, in small rhodium clusters, the effects of binding configuration, surface coverage, metal-supportcharge transfer, and cluster dimension on the vibrational frequency of the C-O bond and the adsorptionenergy of CO to rhodium. In particular, we find a linear correlation between the vibrational frequency of thecarbon-oxygen bond with respect to the metal-carbonyl bond adsorption energy as well as the carbon-oxygen bond length for small rhodium clusters. A semiquantitative relationship is derived that may be usedto calculate bond dissociation enthalpies of rhodium-carbonyl bonds with the use of crystallographic or IRdata associated to the rhodium-carbonyl bond.