On the Cathode Behavior and the Cell Voltage in NaOH Solutions under Elevated Temperatures

Abstract

The overvoltage of the iron, nickel, and Raney Ni electrodes was measured in concentrated solutions under elevated temperatures. Experiments were conducted at 20 atm‐G to prevent water vaporization. With these results, the terminal voltages of the alkaline water electrolysis cell and the chlor‐alkali cell were evaluated to investigate the feasibility of high temperature operation. Iron was corroded seriously by hot concentrated caustic, and was found to be inadequate as the structural material under these conditions. Nickel was resistant to corrosion, but its overvoltage was high. The Raney Ni cathode exhibited very low hydrogen overvoltage characteristics for a short period and degraded irreversibly.