An ultra-high vacuum electrochemical/mass spectrometry study of anodic decomposition of a protic ionic liquid
An ultra-high vacuum electrochemical/mass spectrometry study of anodic decomposition of a protic ionic liquid
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DOI：
10.1016/j.elecom.2018.04.013
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发表时间：
2018-05
影响因子：
5.4
通讯作者：
S. Goodwin;Joshua S. Gibson;Robert G. Jones;D. Walsh
中科院分区：
文献类型：
--
作者：
S. Goodwin;Joshua S. Gibson;Robert G. Jones;D. Walsh
质子离子液体（PIL）是通过质子从布朗斯台德酸转移到布朗斯台德碱而形成的离子液体，并且其被提议用于广泛的电化学装置中。在这方面的贡献，我们描述了电解的PIL二乙基甲基铵三氟甲磺酸在Pd，Pt，和Au电极在超高真空室连接到质谱仪。当电位为-0.8 Vvs.Pd/H时，PIL阳离子发生还原，释放出H2。约2.2 Vvs.Pd/H的正性，发生PIL阴离子的电氧化，导致使用质谱仪检测到许多三氟甲磺酸根离子的碎片。值得注意的是，PIL阴离子的电氧化发生在相同的电位下，而不管是否使用Pt、Au或Pd作为电极。相反，随着电极组成的变化，PIL中水的电氧化在PIL中以不同的电势发生。这些结果表明，PIL的电化学窗口与电极组成无关，但如果液体中存在水，则这种独立性被水的电解所掩盖。
Protic ionic liquids (PILs) are ionic liquids that are formed by proton transfer from Brønsted acids to Brønsted bases, and which are being proposed for use in a wide range of electrochemical devices. In this contribution, we describe electrolysis of the PIL diethylmethylammonium trifluoromethanesulfonate at Pd, Pt, and Au electrodes in an ultra-high vacuum chamber connected to a mass spectrometer. At potentials negative of about −0.8 Vvs.Pd/H, reduction of the PIL cations occurs, liberating H2. Positive of about 2.2 Vvs.Pd/H, electrooxidation of the PIL anions occurs, resulting in the detection of a number of fragments of the trifluoromethanesulfonate ions using the mass spectrometer. Notably, electrooxidation of the PIL anions occurs at the same potential, regardless of whether Pt, Au, or Pd is used as the electrode. In contrast, electrooxidation of water in the PIL occurs at different potentials in the PIL as the electrode composition changes. These results show that the electrochemical window of the PIL is independent of the electrode composition, but if water is present in the liquid, this independence is masked by the electrolysis of water.