关键词: 硅基硼掺金刚石, 原位电化学核磁波谱联用技术, EC-NMR电解池, 电氧化, 对苯二酚

Abstract:

In-situ EC-NMR technique can be used to monitor the electrochemical reaction process in real-time and to explain the reaction mechanism at the molecular level, which is a promising and non-destructive online detection technology. This article for the first time reports the design and production of in-situEC-NMR three-electrode single-chamber electrolytic cell using silicon-based boron-doped diamond (Si/BDD) as the working electrode. Research shows that the geometric size of Si/BDD electrode being 12.5 mm 1.2 mm 0.5 mm in the NMR detection zone is small and the thickness of the electrode material is thin, which accounts for the less hindrance to the radio frequency field, and correspondingly the less damage to the uniformity of the magnetic field. The developed EC-NMR electrolytic cell was tested, and a classic electrochemical reaction of electrooxidation from hydroquinone (QH₂) to benzoquinone (Q) was used as a model system to study the entire dynamic process in-situ. After electrolysis of 0.1 mol·L^-1 QH₂ at a constant potential of 1.2 V for 64 min, it is detected that the characteristic peak intensity of QH₂ at 6.58 ppm was gradually decreased, and the characteristic Q peak at 6.83 ppm was gradually generated. The NMR spectrum peak did not split or broaden significantly during the reaction. The results demonstrate that the in-situ EC-NMR electrolytic cell designed and prepared in this paper can be effectively used for the qualitative and quantitative analyses of the reactants and products in electrochemical reactions, which thus will play an important role in the subsequent researches on electrochemical in-situ NMR spectroscopy.

Key words: Bi/BDD electrode, in-situ EC-NMR, EC-NMR electrolytic cell, electrooxidation, hydroquinone