Desorption of Octanethiol from Gold Electrode Surface
during Its Electrochemical Cleaning

S. N. Ovchinnikova^z and A. Zh. Medvedev

Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch, Russian Academy of Sciences,
ul. Michurina 15, Novosibirsk, 630091 Russia

Received January 20, 2014

Abstract—The potentialities of electrochemical method of removal of adsorbed octanethiol layer from gold
electrode surface are considered. The dependence of a degree of gold macro- and microelectrode cleaning on
the electrolyte composition, potential cycling range, and the number of cycles is studied. It is shown that the
commonly used method of cleaning by multiple potential cycling in the perchloric acid solution in the potential
range from 0 to 1400 mV (SCE) is not sufficiently efficient. Cycling in the water–ethanol solution of perchloric
acid promotes the octanethiol desorption and leads to the complete regeneration of surface even after 6–8
cycles. This is evidenced by comparing with the voltammograms, which were obtained on pure Au surface in
4 mM potassium ferri-ferrocyanide and 0.1 M HClO₄ solutions. A range of ethanol concentrations, which pro-
vides the highest degree of gold surface cleaning, is determined. The electrochemical method of cleaning by
using water–ethanol solution of perchloric acid enables one to perform multiple electrode regeneration without
destruction of thin gold layer (for example, in the quartz microbalance), which takes place in the case of chem-
ical regeneration in the “piranha” solution based on sulfuric acid and hydrogen peroxide.

Keywords: regeneration, gold, octanethiol (OT), ethanol, oxidative desorption

DOI: 10.1134/S1023193515040084

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