Metallic Nature and Surface Diffusion of CO Adsorbed on Ru Nanoparticles in Aqueous Media:  A 13C NMR Study

We report the first observation of the 13C nuclear magnetic resonance spectroscopy (NMR) of 13CO, adsorbed from 13CO saturated 0.5 M sulfuric acid solutions, onto the surfaces of commercial Ru-black nanoparticles. The 13C NMR spectra consist of a symmetrically broadened peak having a large isotropic...

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Veröffentlicht in:The journal of physical chemistry. B 2005-02, Vol.109 (7), p.2474-2477
Hauptverfasser: Babu, Panakkattu K, Chung, Jong Ho, Kuk, Seung Taek, Kobayashi, Takeshi, Oldfield, Eric, Wieckowski, Andrzej
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Sprache:eng
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Zusammenfassung:We report the first observation of the 13C nuclear magnetic resonance spectroscopy (NMR) of 13CO, adsorbed from 13CO saturated 0.5 M sulfuric acid solutions, onto the surfaces of commercial Ru-black nanoparticles. The 13C NMR spectra consist of a symmetrically broadened peak having a large isotropic shift as compared to CO adsorbed onto supported Ru catalysts. The variation of the spin−lattice relaxation rate follows Korringa behavior, indicating the metallic nature of adsorbed CO, in addition to varying across the spectrum in a Korringa-like manner. Motional narrowing of the NMR spectrum at higher temperatures, together with an additional contribution to the spin−lattice relaxation rate, indicate that adsorbed CO undergoes rapid diffusion on the particle surfaces. A two-band model analysis of the NMR results indicates that the CO adsorption bond is weaker on Ru as compared to either Pt or Pd. This is also supported by a reduction in the activation energy for CO diffusion on Ru vs either Pt or Pd nanoparticles.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp040729k