An in situ STM study on the long-range surface restructuring of Au(111) in a non-chloroaluminumated ionic liquid

The Electrode/Ionic Liquid Interface: Electric Double Layer and Metal Electrodeposition

“…On Au(111), the restructuring involves the formation of tiny pits, which then develop into a stable wormlike network with an average width of the network grids of~2 nm, while on Au(100) the etching process can be halted by the formation of a stable cationic adsorption layer. Electrochemical annealing, which is frequently observed in Cl À -containing aqueous solutions and promotes fast diffusion of surface Au atoms and thus smoothes the surface, is also observed on Au (111) [65] is observed only after a smooth surface is recovered through the annealing process.…”

“…[29,65] It is demonstrated that the Au(111) and Au (100) 6 ], as shown in Figure 2. What is unexpected is that such reconstruction could only be observed at sufficiently negative potential where the surface is highly polarized.…”

“…Further comprehensive understanding of the structure and properties of the electric double layer in ionic liquids relies on the employment of well-defined singlecrystal surfaces. Mao and co-workers reported the interfacial behaviors of Au(111) [65] and Au(100) [29] 4 ] on both electrodes show a typical bellshaped feature. On Au(100), independent molecular-resolution in situ STM characterization shows ordered adsorptions of anions and cations at the anodic and cathodic side of the maximum of the bell-shaped capacitance curve, respectively, while no immobilized adsorption of either anions or cations is observed around the potential of the capacitance maximum.…”

“…In 2003, Mao and co-workers started to investigate the reconstruction and restructuring processes of Au single-crystalline electrode surfaces in a neat non-chloroaluminate alkylimidazolium-based ionic liquid. [65] These works are representative of the initial stages of in situ characterization of interfacial electrochemistry in ionic liquids. Despite difficulties in achieving high-resolution STM images in ionic liquid, atomic- [64,66,67] and molecular-resolution [22,29,68,69] imaging has been achieved for some systems.…”

Ionic Liquids for the Future Electrochemical Applications

“…The results indicate that the anion molecules formed Moiré-like patterns at potentials above -0.2 V and adopted a (√3 × √3) structure at approximately -0.45 V although the Moiré patterns often co-existed with uncompressed structures (Fig.3). Mao et al (2003) have observed the drastic long-range surface restructuring with the appearance of small pits. The enlargement of the pits has resulted in forming wormlike structures.…”