Sum Frequency Generation and Catalytic Reaction Studies of the Removal of Organic Capping Agents from Pt Nanoparticles by UV−Ozone Treatment
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- 作者：Cesar Aliaga ; Jeong Y. Park ; Yusuke Yamada ; Hyun Sook Lee ; Chia-Kuang Tsung ; Peidong Yang ; Gabor A. Somorjai
- 刊名：Journal of Physical Chemistry C
- 出版年：2009
- 出版时间：April 16, 2009
- 年：2009
- 卷：113
- 期：15
- 页码：6150-6155
- 全文大小：277K
- 年卷期：v.113,no.15(April 16, 2009)
- ISSN：1932-7455
文摘
We report the structure of the organic capping layers of platinum colloid nanoparticles and their removal by UV−ozone exposure. Sum frequency generation vibrational spectroscopy (SFGVS) studies identify the carbon−hydrogen stretching modes on poly(vinylpyrrolidone) (PVP) and tetradecyl tributylammonium bromide (TTAB)-capped platinum nanoparticles. We found that the UV−ozone treatment technique effectively removes the capping layer on the basis of several analytical measurements including SFGVS, X-ray photoelectron spectroscopy, and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The overall shape of the nanoparticles was preserved after the removal of capping layers, as confirmed by transmission electron microscopy (TEM). SFGVS of ethylene hydrogenation on the clean platinum nanoparticles demonstrates the existence of ethylidyne and di-σ-bonded species, indicating the similarity between single-crystal and nanoparticle systems.