A facile approach to construction of a stable water-miscible ionic liquid/electrolyte interface with interactions between imidazolium moiety and carbon nanotubes

A stable water-miscible ionic imidazolium-based ionic liquid/electrolyte interface is constructed in aqueous media based on the interaction between the imidazolium moiety in ionic liquids (ILs) and single-walled carbon nanotubes (SWNTs). 1-n-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) is used as one kind of typical water-miscible ILs for this study. The nanocomposite of IL and SWNTs is prepared by dispensing SWNTs into IL and the as-prepared nanocomposite is confined onto glassy carbon (GC) electrodes to construct the IL/electrolyte interface. X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy and cyclic voltammetry (CV) results demonstrate that the imidazolium moiety in ILs could interact with SWNTs to form a stable nanocomposite possibly through π-cation or other kinds of interactions between both components. CV results with Fe(CN)64-/3- redox probe suggest the electrochemical interfacial is relatively stable in the aqueous media with a fast electron transfer property. This study may be useful both for the fundamental electrochemical studies and for the practical applications associated with the water-miscible imidazolium-based ILs.