In recent years, ac polarized microelectrodes have been developed and described in literature. The heating is achieved by applying a high frequency ac waveform (~0.1 – 1 GHz, up to 2.4 Vrms) between working and counter electrodes, with the electrical energy being dissipated mainly on a solution resistance near the working microelectrode. The size of the hot zone in solution is determined by the radius of the microelectrode, and heating can easily lead to boiling of the solvent. As a result, the limiting currents at hot microelectrodes can reach values an order of magnitude higher than those at room temperature. We report here the results of the first research steps in the development of a novel technique that we call Hot-Tip Scanning Electrochemical Microscopy (HT-SECM).We have performed experiments in a feedback mode, during which the approach curves were recorded with a hot microelectrode (tip) positioned over an insulator and a conductor (substrates). The tip currents were collected as the tip was brought close to the substrate at room temperature, and when the ac heating was turned on. A series of cyclic voltammetry (CV) experiments were also carried out(with the tip positioned at different distances from the substrates)in order to determine the temperature at the tip from the shift in the half wave potential.The experimental data were supported by the results of the theoretical simulations, which we performed in COMSOL Multiphysics. We expect that the novel technique (HT-SECM) will find important applications in the study of kinetics of electron transfer and coupled chemical reactions. &lt;!--[if !supportLineBreakNewLine]--&gt; &lt;!--[endif]--&gt;

Scanning electrochemical microscopy using AC heated microelectrodes

252nd National Meeting (2016)

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