Structure of [C4mpyr][NTf2] Room-Temperature Ionic Liquid at Charged Gold Interfaces

• Published in: Langmuir Vol. 28; no. 19; pp. 7374 - 7381
• Main Authors: Lauw, Yansen, Horne, Michael D, Rodopoulos, Theo, Lockett, Vera, Akgun, Bulent, Hamilton, William A, Nelson, Andrew R. J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-05-2012
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Surface physical chemistry; Gold; Neutrons; Transition metal; Potential; Ionic liquid; Electrodes; Cyclic voltammetry; Imide; Adsorption; Reflectometry; Capacitance; Structure; Interface; Room temperature; Reflectance
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la3005757

The structure of 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C4mpyr][NTf2]) room-temperature ionic liquid at an electrified gold interface was studied using neutron reflectometry, cyclic voltammetry, and differential capacitance measurements. Subtle differences were observed between the reflectivity data collected on a gold electrode at three different applied potentials. Detailed analysis of the fitted reflectivity data reveals an excess of [C4mpyr]+ at the interface, with the amount decreasing at increasingly positive potentials. A cation rich interface was found even at a positively charged electrode, which indicates a nonelectrostatic (specific) adsorption of [C4mpyr]+ onto the gold electrode.