Impact of glass corrosion on the electrocatalysis on Pt electrodes in alkaline electrolyte

We report on the influence of glass corrosion on establishing the electrocatalytic activity of fuel cell catalysts. A Teflon electrochemical cell was designed for measurements in alkaline electrolyte. The cell performance was tested and compared to a standard electrochemical glass cell by measuring the oxygen reduction reaction and the hydrogen oxidation reaction on polycrystalline platinum in 0.1 M KOH. It is demonstrated that in the Teflon cell the shape of the cyclic voltammogram as well as the activity for the reactions are reproducible and do not alter over a long period of time. By comparison, using the standard electrochemical cell made out of Duran glass, it is found that the experiments on polycrystalline Pt electrodes in alkaline electrolyte are insufficiently reproducible. The cyclic voltammograms alter over time, and the activities of the hydrogen oxidation as well as the oxygen reduction depend on the applied potential scan limits. This is due to the contamination of the electrolyte because of the etching of glass by KOH, which is further supported with an analysis of the alkaline electrolyte after usage in the respective cell types by inductively coupled plasma-optical emission spectroscopy. (c) 2007 The Electrochemical Society.