Initial stages of Pd deposition on Au(hkl) part II:: Pd on Au(100)
Initial stages of Pd deposition on Au(hkl) part II:: Pd on Au(100)
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DOI：
10.1016/s0039-6028(00)00569-0
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发表时间：
2000-08-01
期刊：
影响因子：
1.9
通讯作者：
Kolb, DM
中科院分区：
文献类型：
--
作者：
Kibler, LA;Kleinert, M;Kolb, DM
用原位扫描隧道显微镜和循环伏安法研究了无岛表面和有岛覆盖表面的Pd在未重建的Au(100)表面的沉积。在裸露的Au(100)表面上，观察到了吸附的[PdCl4](2-)的(3x根10)-结构，并带有配体原子的原子分辨图像。在Au(100)上的欠电位下沉积了相当于一个Pd单分子膜。在得到的层的顶部形成了扭曲的六边形氯化物附着层。Pd在有岛覆盖的Au(100)表面上的生长机制与在无岛表面的明显不同。在过电位区，Pd薄膜外延生长，在较高覆盖率时，阶跃密度略有增加。这些较厚的Pd覆盖层的行为非常类似于块状Pd(100)单晶的表面，而Au(100)上的第一个Pd层具有明显不同的电化学行为。Pd溶解后出现的小Au岛指向欠电位区表面合金的形成。(C)2000 Elsevier Science B.V.保留所有权利。
The deposition of Pd onto unreconstructed Au(100) was studied by in situ scanning tunnelling microscopy and cyclic voltammetry for both an island-free surface and one covered with islands that originate from lifting of the (hex)-reconstruction. On the bare Au(100) surfaces, a (3 x root 10)-structure of adsorbed [PdCl4](2-) with atomically resolved images of the ligand atoms was observed. An equivalent of about one Pd monolayer is deposited at underpotentials on Au(100). On top of the resulting layer a distorted-hexagon chloride adlayer is formed. The growth mechanism for Pd on island-covered Au(100) is markedly different from that for the island-free surface. In the overpotential region, Pd films grow epitaxially with a slightly increased step density at higher coverage. These thicker Pd overlayers behave very similar to surfaces of massive Pd(100) single crystals, whereas the first Pd layers on Au(100) have a clearly different electrochemical behaviour. The presence of small Au islands after dissolution of Pd points towards surface alloy formation in the underpotential region. (C) 2000 Elsevier Science B.V. All rights reserved.