Studies on Chlorate Cell Process: III . Depolarization of Cathodic Hydrogen Evolution in the Bipolar Chlorate Cell Process

The cathode process of hydrogen evolution in chlorate cells, including possible depolarization, has not been studied to date. High hydrogen polarization at graphite electrodes delayed the industrial application of bipolar cells for more than 80 years. A new method of depolarization has been developed which consists of depositing on the cathode side of a graphite electrode metallic chromium and/or an addition of small amounts of molybdate. The finely divided cathode molybdenum deposit decreases the cathode polarization for the hydrogen evolution reaction (h.e.r.). The Tafel lines obtained on metallized graphite exhibit nearly the same slopes as the ones for the parent metals, but are shifted to more positive values. This represents a further extension of the methods for depolarized hydrogen cathode evolution with metallized graphite (8,9)