title: Mono- and multi-layer adsorption of an ionic liquid on Au(110).
abstract: Ultraviolet photoelectron spectroscopy (UPS), work function measurements, low energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) have been used to study the adsorption and desorption of 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [C(2)C(1)Im][Tf(2)N], on the (1×2) clean surface reconstruction of Au(110) in the temperature range 100-674 K. The ionic liquid adsorbed without decomposition, and desorbed without leaving any residue on the surface. For adsorption at room temperature a monolayer of strongly bound ionic liquid was formed with four interface states visible in UP spectra. STM at 100 K showed that the monolayer consisted of well-ordered rows of adsorbed ionic liquid aligned parallel to the close packed rows of surface gold atoms (the [110] direction) with a separation of ×2 (the same as the clean surface reconstruction) between the rows in the orthogonal [001] direction. Multilayer adsorption at room temperature occurred by droplet formation followed by smoothing of the droplets to a layered morphology with time. Heating caused multilayer desorption at temperatures in the 363-383 K range, followed by partial monolayer desorption at 548 K to produce a Au(110)-(1×3) reconstructed surface with sub-monolayer domains of ionic liquid. Desorption of the remaining ionic liquid at 600 K caused the gold surface to reconstruct back to the clean (1×2) reconstruction.
authors.affiliation: Department of Physical Chemistry, School of Chemistry, University of Nottingham, Nottingham, NG7 2RD.
authors.forename: Richard
authors.initials: R
authors.lastname: Foulston
authors.forename: Subhashis
authors.initials: S
authors.lastname: Gangopadhyay
authors.forename: Cristina
authors.initials: C
authors.lastname: Chiutu
authors.forename: Philip
authors.initials: P
authors.lastname: Moriarty
authors.forename: Robert G
authors.initials: RG
authors.lastname: Jones