The interface between HOPG and 1-butyl-3-methyl-imidazolium hexafluorophosphate

Abstract

The interface between highly oriented pyrolytic graphite (HOPG) and 1-butyl-3-metyl-imidazolium hexafluorophosphate (BMIPF6) has been studied using cyclic voltammetry, electrochemical impedance spectroscopy, immersion charge measurements and in-situ scanning tunneling microscopy (insitu STM). The results are compared with those obtained with Au(100) in BMIPF6 (Phys.Chem.Chem.Phys., 2011, 13, 11627). The main result is that the high frequency capacitance spectra on the two systems are similar to each other, however at low frequencies some slow interfacial processes cause the appearance of a second capacitance arc on Au(100), which is absent for HOPG. The slow processes are attributed to the rearrangement of the Au surface structure and to the formation of ionic liquid adlayers -these are visualized by in-situ STM.

Electrochemical impedance spectroscopy in interfacial studies

“…As evidenced by in-situ STM imaging, contrary to a rigid and inert structure of the HOPG surface, the Au(100) surface in contact with ILs undergoes a slow rearrangement phenomena and a distinct corrosion processes. These findings explain the presence and absence of of Z 2 in the equivalent circuit for Au(100) and HOPG, respectively [6]. 3.…”

The metal–ionic liquid interface as characterized by impedance spectroscopy andin situscanning tunneling microscopy

“…Since then, we have performed many measurements; the reports on these are given in ref. [31][32][33][34][35][36][37][38]. The present overview is a summary of the obtained findings, extended with new measurements, in order to draw a more complete picture of these interesting systems.…”

Fundamental aspects of electric double layer force-distance measurements at liquid-solid interfaces using atomic force microscopy

“…In recent years numerous efforts have gone toward understanding the complex structure of ILs at the solid-liquid interface using both theoretical approaches6789101112 and experimental methods such as scattering techniques131415, sum-frequency generation161718, surface-force apparatus19202122232425, and scanning probe techniques. For the latter, scanning tunneling microscopy (STM)2627282930313233343536 and dynamic3738394041 and static42434445464748495051 atomic force microscopy (AFM) approaches have made large progress towards imaging the ion layers in two and three dimensions at neutral and charged surfaces such as mica, silica, gold, and highly-oriented pyrolytic graphite (HOPG). Scanning probe microscopy based techniques offer the advantage of high spatial resolution in three dimensions compared to other techniques, allowing for the ion structure to be visualized in a 3D manner, as opposed scattering techniques and SFA where the response is averaged over large areas.…”