Mono- and multi-layer adsorption of an ionic liquid on Au(110)
Mono- and multi-layer adsorption of an ionic liquid on Au(110)
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DOI：
10.1039/c2cp23901a
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Jones, Robert G.
中科院分区：
文献类型：
--
作者：
Foulston, Richard;Gangopadhyay, Subhashis;Jones, Robert G.
利用紫外光电子能谱（UPS）、功函数测量、低能电子衍射（LEED）和扫描隧道显微镜（STM）研究了100-674 K温度范围内1-乙基-3-甲基咪唑双[（三氟甲基）磺酰基]酰亚胺[C（2）C（1）Im][Tf 2N]在Au（110）（1 × 2）清洁重构表面上的吸附和脱附.该离子液体吸附而不分解，并且解吸而不在表面上留下任何残留物。对于在室温下的吸附，形成了一个单层的强结合的离子液体与四个界面态在UP光谱中可见。在100 K的STM表明，单层由有序排列的吸附离子液体行平行于紧密堆积的表面金原子行（[110]方向），在正交[001]方向上的行之间的间距为x2（与清洁表面重建相同）。在室温下发生的多层吸附液滴形成，然后通过平滑的液滴随时间的分层形态。加热引起在363-383 K范围内的温度下的多层脱附，然后在548 K下部分单层脱附以产生具有离子液体的亚单层域的Au（110）-（1x 3）重构表面。剩余离子液体在600 K下的解吸导致金表面重建回到干净的（1x 2）重建。
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][Tf2N], on the (1x2) 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 x2 (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)-(1x3) 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 (1x2) reconstruction.