The initial stages of palladium deposition onto Pt(1 1 1)
The initial stages of palladium deposition onto Pt(1 1 1)
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DOI：
10.1016/j.electacta.2003.07.008
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发表时间：
2003-12
影响因子：
6.6
通讯作者：
R. Hoyer;L. A. Kibler;D. Kolb
中科院分区：
文献类型：
--
作者：
R. Hoyer;L. A. Kibler;D. Kolb
通过循环伏安法和原位扫描隧道显微镜研究了含 PdCl2 和 PdSO4 溶液中 Pd 电沉积到 Pt(111) 上的情况。在这两种情况下，钯沉积都是从形成假晶单层开始的。当存在氯化物时，该单层在低电势下沉积，但其在无氯化物溶液中的形成在动力学上受到阻碍，以致沉积峰向平衡电势的负值移动。从有关 Pd 层以及共吸附阴离子的 STM 数据中获得了详细的结构信息。含氯化物溶液的本体沉积通过准逐层方式进行。然而，只有在沉积了相当于四个以上的 Pd 层后，第一个 Pd 单层的特殊电化学性质才消失。此类薄膜的电化学行为类似于粗糙的 Pd(111) 表面。无氯化物溶液中的钯大量沉积从一开始就导致三维簇的形成。在这种情况下，需要大约 10 ML 当量才能完全覆盖第一个 Pd 单层。
The electrodeposition of Pd onto Pt(111) from PdCl2and PdSO4containing solutions was studied by cyclic voltammetry and in situ scanning tunnelling microscopy. Pd deposition starts by forming a pseudomorphic monolayer in both cases. While in the presence of chloride this monolayer is deposited at underpotentials, its formation in chloride-free solution is kinetically hindered to such an extent that the deposition peak is shifted negative of the equilibrium potential. Detailed structure information has been obtained from STM data about the Pd layer as well as the co-adsorbed anions. Bulk deposition from the chloride-containing solution proceeds via a quasi layer-by-layer fashion. However, the particular electrochemical properties of the first Pd monolayer disappear only after deposition of the equivalent of four more Pd layers. The electrochemical behaviour of such films is similar to that of a rough Pd(111) surface. Pd bulk deposition from chloride-free solution leads to the formation of three-dimensional clusters from the very beginning. About 10 ML equivalents are needed in that case to completely cover the first Pd monolayer.