Dual-Plate Gold-Gold Microtrench Electrodes for Generator-Collector Voltammetry without Supporting Electrolyte

• Published in: Electrochimica acta Vol. 224; pp. 487 - 495
• Main Authors: Montiel, Miguel A., Iniesta, Jesus, Gross, Andrew J., Marken, Frank
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 10.01.2017; Elsevier BV; Elsevier
• Subjects: Chemical Sciences; diffusion; Electrodes; Electrolytes; feedback; Gold; ionic strength; Oxidation; Scanning; sensing; Steady state; voltammetry; feedback; sensing; diffusion; voltammetry; ionic strength
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.11.103

[Display omitted] •Generator-collector voltammetry in low electrolyte conditions.•Analytical current responses insensitive to electrolyte levels.•Diffusion effects within the dual-plate microtrench electrode and pre-electrolysis effects. A gold-gold dual-plate microtrench electrode system based on two oppositely placed gold surfaces with 5mm length, 17μm average depth, and 6μm inter-electrode gap is employed in generator-collector configuration in a four-electrode cell (counter electrode, reference electrode, and two independent working electrodes denoted “generator” – with scanning potential – and “collector” – with fixed potential). The dual-plate microtrench electrodes were investigated for (i) the reduction of Ru(NH3)63+, (ii) the oxidation of ferrocenemethanol, and (iii) the oxidation of iodide in aqueous media, all as a function of supporting electrolyte concentration. It is shown that due to the inter-electrode feedback character of the generator-collector currents, well-defined steady state sensor responses are obtained for the collector electrode even in the absence of added electrolyte. The variation in the mass transport limited steady state current (measured at the collector electrode) with addition/removal of supporting electrolyte remains low (compared to unexpectedly stronger effects caused by the switch between reduction and oxidation conditions at the collector electrode). Microtrench electrode systems are suggested for sensing applications without/with varying levels of supporting electrolyte.