Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA.
Anal Chem. 2012 Feb 7;84(3):1609-16. doi: 10.1021/ac2028672. Epub 2012 Jan 25.
Here we report the voltammetric study of coupled electrochemical reactions on microelectrodes and nanoelectrodes in a closed bipolar cell. We use steady-state cyclic voltammetry to discuss the overall voltammetric response of closed bipolar electrodes (BPEs) and understand its dependence on the concentration of redox species and electrode size. Much of the previous work in bipolar electroanalytical chemistry has focused on the use of an "open" cell with the BPE located in an open microchannel. A closed BPE, on the other hand, has two poles placed in separate compartments and has remained relatively unexplored in this field. In this work, we demonstrated that carbon-fiber microelectrodes when backfilled with an electrolyte to establish conductivity are closed BPEs. The coupling between the oxidation reaction, e.g., dopamine oxidation, on the carbon disk/cylinder and the reduction of oxygen on the interior fiber is likely to be responsible for the conductivity. We also demonstrated the ability to quantitatively measure voltammetric properties of both the cathodic and anodic poles in a closed bipolar cell from a single cyclic voltammetry (CV) scan. It was found that "secondary" reactions such as oxygen reduction play an important role in this process. We also described the fabrication and use of Pt bipolar nanoelectrodes which may serve as a useful platform for future advances in nanoscale bipolar electrochemistry.
我们在此报告了在封闭双极池中微电极和纳米电极上耦合电化学反应的伏安研究。我们使用稳态循环伏安法讨论了封闭双极电极（BPE）的整体伏安响应，并了解了其对氧化还原物种浓度和电极尺寸的依赖性。双极电分析化学的先前大部分工作都集中在使用带有 BPE 的“开放式”池在开放式微通道中进行。另一方面，封闭的 BPE 具有两个电极分别位于两个隔室中，在该领域中相对未得到充分探索。在这项工作中，我们证明了当碳纤维微电极用电解质填充以建立导电性时，它们就是封闭的 BPE。碳盘/圆柱体上的氧化反应（例如多巴胺氧化）与内部纤维上的氧还原之间的耦合可能是导电性的原因。我们还证明了从单个循环伏安（CV）扫描中定量测量封闭双极池中阴极和阳极极的伏安性质的能力。结果发现，“次级”反应（例如氧还原）在该过程中起着重要作用。我们还描述了 Pt 双极纳米电极的制造和使用，它们可能成为纳米尺度双极电化学未来发展的有用平台。
