Anisotropic etching of platinum electrodes at the onset of cathodic corrosion

• DOI: 10.1038/ncomms12653
• Publication Date: 2016-08-24T10:51:48Z
• Authors: Thomas J. P. Hers...; Alexei I. Yanson; Marc T. M. Koper
• Keywords: Standard electrode potential

Cathodic corrosion is a process that etches metal electrodes under cathodic polarization. This presumed to occur through anionic metallic reaction intermediates, but the exact nature of these intermediates and onset potential their formation unknown. Here we determine on platinum electrodes. Electrodes are characterized electrochemically before after polarization in 10 M sodium hydroxide, revealing changes electrode surface start at an -1.3 V versus normal hydrogen electrode. The value this rules out previous hypotheses regarding corrosion. Scanning electron microscopy shows well-defined etch pits with specific orientation, which match voltammetric data indicate remarkable anisotropy etching process, favouring creation (100) sites. Such hypothesized be due charge-induced adsorption electrolyte cations.