Abstract Protic ionic liquids (PILs) are promising electrolytes for electrochemical devices, owing to their wide electrochemical stability, good ionic conductivity, low vapour pressure and good thermal stability. In this study, we demonstrate that [Dema-H]+[TfO]- can be used as an electrolyte for intermediate temperature water electrolysis. The cyclic voltammograms of [Dema-H]+[TfO]- on Pt show a potential window of 2.5 V which is beyond water decomposition potential of 1.23 V. Two hydrogen evolution reactions are observed on Pt electrode in both “as prepared” [Dema-H]+[TfO]- and 10% [Dema-H]+[TfO]- in water. The first HER involving H3O+ had a peak potential at −0.255 V (vs SHE with limiting current density of 0.016 mA/cm2 assigned to Pt low surface coverage/adsorption of H+/H3O+. The second HER involving [Dema-H]+ had an on-set at −0.475 V vs SHE and did not show limiting current up to 0.1 mA cm−2 (−0.8 V vs. SHE). Second observed HER is believed to be due to reduction of two [Dema-H]+ to produce H2 and diethyl methyl amine [Dema]. The latter is reoxidised at anode to reproduce [Dema-H]+. In-situ mass spectrometric analysis confirmed H2/O2 evolution at both potentials. The oxygen evolution reaction (OER) on IrO2 in 10% [Dema-H]+[TfO]- also shows two onset potentials.

中文翻译：

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用于水电解的二乙基甲基三氟甲磺酸铵质子离子液体电解质

摘要 质子离子液体（PILs）具有广泛的电化学稳定性、良好的离子电导率、低蒸气压和良好的热稳定性，是一种很有前途的电化学器件电解质。在这项研究中，我们证明了 [Dema-H]+[TfO]- 可用作中温水电解的电解质。[Dema-H]+[TfO]- 在 Pt 上的循环伏安图显示 2.5 V 的电位窗口，超过了 1.23 V 的水分解电位。在“准备好的”[Dema -H]+[TfO]- 和 10% [Dema-H]+[TfO]- 在水中。涉及 H3O+ 的第一个 HER 的峰值电位为 -0.255 V（与 SHE 相比，限制电流密度为 0.016 mA/cm2，归因于 Pt 低表面覆盖/吸附 H+/H3O+。涉及 [Dema-H]+ 的第二个 HER 具有在-0开始。475 V vs SHE，并且没有显示出高达 0.1 mA cm-2 的限制电流（-0.8 V vs. SHE）。第二次观察到的 HER 被认为是由于两个 [Dema-H]+ 还原产生 H2 和二乙基甲胺 [Dema]。后者在阳极被再氧化以产生[Dema-H]+。原位质谱分析证实了两种电位的 H2/O2 演化。IrO2 在 10% [Dema-H]+[TfO]- 中的析氧反应 (OER) 也显示出两个起始电位。