Direct Visualization of Soliton CO Overlayers on Supported Pd Nanoparticles
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- 作者：Chi M. Yim ; Chi L. Pang ; Geoff Thornton
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：September 24, 2015
- 年：2015
- 卷：119
- 期：38
- 页码：22044-22049
- 全文大小：505K
- ISSN：1932-7455
文摘
The interaction of carbon monoxide (CO) molecules with the facets of noble metal nanoparticles forms the basis of many important catalytic reactions. Using scanning tunneling microscopy (STM), we have studied the adsorption of CO molecules on the (111) facets of Pd nanocrystals supported on a rutile TiO2(110) substrate. We observed four compact CO overlayers with coverages ranging between 0.5 and 0.6 monolayers. Examination of the positions of the CO molecules in each of the unit cells reveals that one of the overlayers has a rhombic (鈭? 脳 鈭?) R19.1掳-4CO structure. The other three form rectangular structures, namely, (7 脳 鈭?) rect-8CO, c(5 脳 鈭?) rect-3CO, and c(9 脳 鈭?) rect-5CO. These are closely related via a soliton model previously proposed on the basis of infrared absorption spectroscopy and low-energy electron diffraction. By imaging the CO molecules, we provide direct evidence for the soliton model.