Department of Physical Chemistry, Justus-Liebig-University , Heinrich-Buff-Ring 58, D-35392 Gießen, Germany.
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Key Laboratory for Green Preparation and Application for Functional Materials, Ministry of Education, Faculty of Materials Science & Engineering, Hubei University , Wuhan 430062, China.
Langmuir. 2016 May 31;32(21):5291-9. doi: 10.1021/acs.langmuir.6b01139. Epub 2016 May 20.
We examined the interaction of oxygen with ultrathin Ru layers deposited on a Au(111) substrate using scanning tunneling microscopy, X-ray photoelectron spectroscopy, and low-energy electron diffraction. The deposition of pure Ru below one monolayer (ML) at room temperature leads to the formation of clusters on the Au(111) surface, preferentially located at the elbow sites of the herringbone reconstruction. Subsequent exposure of molecular oxygen to such a Ru-covered Au(111) surface at 680 K results in the growth of two-layer-thick Ru islands that are embedded in the top Au(111) layer. This structural reorganization of Ru is driven by the minimization of surface energy and mediated by a mobile RuOx species. Deposition of an increasing amount of Ru at 620 K (0.5-10 ML, ML = monolayer) leads to a rough Ru film on Au(111). Subsequent oxygen treatment (10(-5) mbar) at 680 K creates either a porous Ru film (<4 ML) or a flat RuO2(110) film (>6 ML) depending on the thickness of the Ru film.
我们使用扫描隧道显微镜、X 射线光电子能谱和低能电子衍射研究了氧气与沉积在 Au(111) 衬底上的超薄 Ru 层的相互作用。在室温下低于单层（ML）的纯 Ru 沉积会导致在 Au(111)表面形成团簇，优先位于鱼骨重建的肘部位置。随后，将分子氧暴露于这样的 Ru 覆盖的 Au(111)表面在 680 K 下导致双层厚的 Ru 岛的生长，该 Ru 岛嵌入在顶部 Au(111)层中。Ru 的这种结构重排是由表面能的最小化驱动的，并由可移动的 RuOx 物种介导。在 620 K 下（0.5-10 ML，ML = 单层）沉积越来越多的 Ru 会导致 Au(111)上的粗糙 Ru 膜。随后在 680 K 下（10(-5) mbar）进行氧气处理会根据 Ru 膜的厚度创建多孔 Ru 膜（<4 ML）或平坦 RuO2(110)膜（>6 ML）。
