Adsorption of Solvent Cations on Au(111) and Au(100) in Alkylimidazolium-Based Ionic Liquids – Worm-Like versus Micelle-Like Structures
Adsorption of Solvent Cations on Au(111) and Au(100) in Alkylimidazolium-Based Ionic Liquids – Worm-Like versus Micelle-Like Structures
复制标题
DOI：
10.1524/zpch.2012.0255
复制
发表时间：
2012-10
期刊：
影响因子：
--
通讯作者：
Yu-Zhuan Su;Jiawei Yan;Mian-Gang Li;Zhaoxiong Xie;B. Mao;Z. Tian
中科院分区：
文献类型：
--
作者：
Yu-Zhuan Su;Jiawei Yan;Mian-Gang Li;Zhaoxiong Xie;B. Mao;Z. Tian
摘要 采用高分辨率原位STM，系统研究了EMI+、PMI+、BMI+和OMI+等烷基咪唑基阳离子在Au(111)和Au(100)表面的吸附。 Au(111) 和 Au(100) 上的阳离子吸附均由相对的咪唑基阳离子对产生的双排组成。在Au(100)上，与四个阳离子相关的双排沿着Au(100)表面晶格单元的两个√2方向显示出胶束状外观。双排的宽度根据阳离子的侧链长度而变化，但受到沿√ 2 方向的周期性的限制。 BF4-、PF6-、CF3SO3-和Tf2N-阴离子不影响胶束状吸附结构。在 Au(111) 上，只有当平台被蚀刻到几个原子宽时，才会形成双行。最有可能的是，下面的金表面经历了重组以适应双排结构，并且双排的蠕虫状方向是应变释放的结果。当表面被驱动进行普通的 Au(100)-hex 和 Au(111)-(√ 3 × 22) 重建时，胶束状和蠕虫状吸附结构都会在阴极电位偏移时被提升。这些结果表明Au(100)上的有序胶束状结构和Au(111)上的不规则蠕虫状结构具有相同的性质。
Abstract By employing high resolution in-situ STM, the adsorption of alkylimidazolium-based cations of EMI+, PMI+, BMI+ and OMI+ on Au(111) and Au(100) surfaces are investigated systematically. The cation adsorption on both Au(111) and Au(100) are composed of double rows arising from counter-facing imidazolium-based cation pairs. On Au(100), the double rows associated with the four cations show micelle-like appearance along the two √ 2 directions of the Au(100) surface lattice units. The width of the double rows varies depending on the side chain length of the cations, but is constrained by the periodicity along the √ 2 directions. Anions of BF4-, PF6-, CF3SO3- and Tf2N- do not influence the micelle-like adsorption structure. On Au(111), the double rows are formed only when the terraces are etched to several atoms wide. Most likely, the underneath Au surface experiences restructuring to accommodate the double row structure, and the worm-like orientation of the double rows is the consequence of strain release. Both the micelle-like and worm-like adsorption structures would be lifted upon cathodic potential excursions when the surfaces are driven to undergo ordinary Au(100)-hex and Au(111)-(√ 3 × 22) reconstructions. These results reveal that the ordered micelle-like structure on Au(100) and the irregular worm-like structure on Au(111) are of the same nature.