Hay Catherine E, Lee Junqiao, Silvester Debbie S
Curtin Institute for Functional Molecules and Interfaces, School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth 6845, WA, Australia.
Nanomaterials (Basel). 2019 Aug 15;9(8):1170. doi: 10.3390/nano9081170.
Microelectrodes offer higher current density and lower ohmic drop due to increased radial diffusion. They are beneficial for electroanalytical applications, particularly for the detection of analytes at trace concentrations. Microelectrodes can be fabricated as arrays to improve the current response, but are presently only commercially available with gold or platinum electrode surfaces, thus limiting the sensing of analytes that are more electroactive on other surfaces. In this work, gold (Au), copper (Cu), and palladium (Pd) are electrodeposited at two different potentials into the recessed holes of commercial microelectrode arrays to produce 3-dimensional (3D) spiky, dendritic or coral-like structures. The rough fractal structures that are produced afford enhanced electroactive surface area and increased radial diffusion due to the 3D nature, which drastically improves the sensitivity. 2,4,6-trinitrotoluene (TNT), carbon dioxide gas (CO), and hydrogen gas (H) were chosen as model analytes in room temperature ionic liquid solvents, to demonstrate improvements in the sensitivity of the modified microelectrode arrays, and, in some cases (e.g., for CO and H), enhancements in the electrocatalytic ability. With the deposition of different materials, we have demonstrated enhanced sensitivity and electrocatalytic behaviour towards the chosen analytes.
微电极由于径向扩散增加而具有更高的电流密度和更低的欧姆降。它们有利于电分析应用，特别是用于检测痕量浓度的分析物。微电极可以制成阵列以改善电流响应，但目前只有金或铂电极表面的微电极在市场上有售，因此限制了对在其他表面上更具电活性的分析物的传感。在这项工作中，金（Au）、铜（Cu）和钯（Pd）在两个不同电位下电沉积到商业微电极阵列的凹孔中，以产生三维（3D）尖刺状、树枝状或珊瑚状结构。所产生的粗糙分形结构由于其3D性质而提供了增强的电活性表面积和增加的径向扩散，从而极大地提高了灵敏度。选择2,4,6-三硝基甲苯（TNT）、二氧化碳气体（CO）和氢气（H）作为室温离子液体溶剂中的模型分析物，以证明修饰后的微电极阵列灵敏度的提高，并且在某些情况下（例如对于CO和H），还证明了电催化能力的增强。通过沉积不同的材料，我们已经证明了对所选分析物具有增强的灵敏度和电催化行为。
