Surface Investigation of Intermetallic PdGa(1̅鈥?̅鈥?̅)
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- 作者：Dirk Rosenthal ; Roland Widmer ; Ronald Wagner ; Peter Gille ; Marc Armbr眉ster ; Yuri Grin ; Robert Schl枚gl ; Oliver Gr枚ning
- 刊名：Langmuir
- 出版年：2012
- 出版时间：May 1, 2012
- 年：2012
- 卷：28
- 期：17
- 页码：6848-6856
- 全文大小：437K
- 年卷期：v.28,no.17(May 1, 2012)
- ISSN：1520-5827
文摘
The intermetallic PdGa is a highly selective and potent catalyst in the semihydrogenation of acetylene, which is attributed to the surface stability and isolated Pd atom ensembles. In this context PdGa single crystals of form B with (1̅鈥?̅鈥?̅) orientation were investigated by means of X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM), X-ray photoelectron diffraction (XPD), and low-energy electron diffraction (LEED) to study the electronic and geometric properties of this surface. UPS and thermal desorption spectroscopy (TDS) were used to probe the chemisorption behavior of CO. The PdGa(1̅鈥?̅鈥?̅) surface exhibits a (1 脳 1) LEED and a pronounced XPD pattern indicating an unreconstructed bulk-truncated surface. Low-temperature STM reveals a smooth surface with a (1 脳 1) unit cell. No segregation occurs, and no impurities are detected by XPS. The electronic structure and the CO adsorption properties reveal PdGa(1̅鈥?̅鈥?̅) to be a bulk-truncated intermetallic compound with Pd鈥揋a partial covalent bonding.