Generator-collector Voltammetry at Dual-plate Gold-gold Microtrench Electrodes as Diagnostic Tool in Ionic Liquids

Ionic liquids provide high viscosity solvent environments with interesting voltammetric characteristics and new electrochemical mechanisms. Here, a gold-gold dual-plate microtrench electrode is employed in generator-collector mode to enhance viscosity-limited currents in ionic liquids due to fast feedback within small inter-electrode gaps (5 μm inter-electrode gap, 27 μm microtrench depth) and to provide a mechanistic diagnosis tool. Three redox systems in the ionic liquid BMIm+BF4− are investigated: (i) ferrocene oxidation, (ii) oxygen reduction, and (iii) 2-phenyl-naphthyl-1,4-dione reduction. Both transient and steady state voltammetric responses are compared. Asymmetric diffusion processes, reaction intermediates, and solubility changes in the ionic liquid are revealed.A. J. G and F. M. gratefully acknowledge the Engineering and Physical Sciences Research Council (EP/I028706/1) for financial support. M. A. M. and J. I. also thank the financial support from MICINN-FEDER (Spain) through the project CTQ2013-48280-C3-3-R