RESUMEN
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 (in situ 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.
RESUMEN
The electrochemical interface of Au(100) and 1-butyl-3-methyl-imidazolium hexafluorophosphate has been characterized by cyclic voltammetry, electrochemical impedance spectroscopy and in situ STM, especially in two distinct potential ranges. In the vicinity of the potential of zero total charge--the value of which has been determined by immersion experiments--charging of the double layer is rather slow, it appears as if the ions comprising the ionic liquid would slowly exchange each other at the surface. In the other, very negative region the ordering of the cations has been observed by STM.