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Hysteresis of Potential-Dependent Changes in Ion Density and Structure of an Ionic Liquid on a Gold Electrode: In Situ Observation by Surface-Enhanced Infrared Absorption Spectroscopy
journal contribution
posted on 2015-12-16, 23:33 authored by Kenta Motobayashi, Kazuya Minami, Naoya Nishi, Tetsuo Sakka, Masatoshi OsawaPotential-dependent structure and
dynamics of 1-butyl-3-methylimidazolium
bis(trifluoromethanesulfonyl)amide ([BMIM][TFSA]) on an Au electrode
have been investigated by using surface-enhanced infrared absorption
spectroscopy (SEIRAS). In situ, real-time IR measurements during potential
scans enable us to probe a hysteretic exchange and reorientation of
both the cation and anion at the interface simultaneously owing to
the high interface selectivity and sensitivity of SEIRAS. Our experimental
results reveal that during potential scans, the ion density in overlayers
changes first, and then the exchange of the ions in the first ionic
layer occurs to compensate the changes in surface charge.