Effect of Platinum Nanocluster Size and Titania Surface Structure upon CO Surface Chemistry on Platinum-Supported TiO2 (110)
The adsorption chemistry of CO on clean and Pt-supported TiO{sub 2} (110) was investigated. It was found that surface structure of TiO{sub 2} plays an important role in the chemistry that takes place at the surface. On the reduced (1 x 2)-reconstructed surface, CO desorbed at 140 and 170 K, while only desorption at 140 K was observed on the stoichiometric (1 x 1) surface. Additionally, CO dissociation, possibly due to the reduction by Ti{sup 3+}, was observed on the Pt-supported (1 x 2) surface. On the Pt-covered surfaces, the chemistry of CO adsorption and desorption strongly depends on the size of Pt nanoclusters. With a decrease in cluster size, CO was found to desorb at higher temperatures. This unusual desorption chemistry is likely related to quantum size effects of Pt nanoclusters. Scanning tunneling spectra revealed that clusters below 20 {angstrom} in diameter exhibited nonmetallic behavior, while those above 40 {angstrom} were metallic. This transition of the properties of Pt nanoclusters from metallic to nonmetallic as the cluster size decreases correlates with stronger interaction of CO with Pt observed in temperature-programmed desorption spectra.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1033471
- Report Number(s):
- PNNL-SA-34652; TRN: US201202%%770
- Journal Information:
- Journal of Physical Chemistry B, Vol. 105, Issue 12; ISSN 1520-6106
- Country of Publication:
- United States
- Language:
- English
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