期刊
ELECTROCHIMICA ACTA
卷 384, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.electacta.2021.138412
关键词
Microelectrode arrays; Electrodeposition; Overlapping diffusion; Platinum deposition; Oxygen sensing; Room temperature ionic liquids
资金
- Australian Research Council [FT170100315]
- University, State and Commonwealth Governments of Australia
- Australian Research Council [FT170100315] Funding Source: Australian Research Council
Microelectrodes are popular in electroanalysis for high current density, which can be further increased by multiplying the number of electrodes in an array configuration. The spacing between microelectrodes significantly affects the deposition effects and current responses, with smaller spacing potentially allowing for higher electrode density.
Microelectrodes are popular in electroanalysis because radial diffusion to the electrodes results in high current density. The current can then be multiplied by increasing the number of electrodes in an array configuration, allowing for low concentrations of analyte species to be detected. Microelectrode arrays are usually designed so that individual microelectrodes (in a hexagonal arrangement) are sufficiently spaced, ensuring that diffusion layers do not overlap during electrochemical experiments, but are not too far separated so that space is wasted. In this study, the effect of microelectrode spacing has been investigated for platinum deposition into the microholes of commercially available microarray devices. The microarrays have 91 recessed microelectrodes, 10 mu m in diameter, 3.3 mu m depth, but with four different centre to-centre spacings of 80, 60, 40 and 20 mu m (8, 6, 4 and 2 times the diameter). A 300 s deposition time in an aqueous hexachloroplatanic acid solution was used to deposit three-dimensional Pt structures into the array. The size of the deposits systematically decreased as the electrode spacing became smaller, as a result of overlapped diffusion layers during the deposition process. The modified microarrays were then used for the sensing of a model analyte (oxygen) in a room temperature ionic liquid, with the larger deposits (with larger surface areas) giving higher current responses. However, current densities were found to be quite comparable for all spacings. The 2 times diameter separation can theoretically fit 16 times the number of electrodes into the same area of the underlying Au electrode compared to the 8 times separation. Therefore, it should be possible to design devices that have significantly higher electrode density, which can maximise the overall current and lead to better analytical performances. This work shows that it is important to consider both the geometry and electrode separation for microarrays when used in electrodeposition and for electroanalytical applications. (c) 2021 Elsevier Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据