Activity and corrosion of tungsten carbide recombination electrodes during lead/acid battery operation

Abstract

The oxidation of the tungsten carbide (WC) catalyst in recombination electrodes partially immersed in H 2SO 4 solution was investigated when the electrodes operated in an atmosphere of oxygen and hydrogen. It has been established that after a long operation period (400 h) 60 to 70% of the catalysts, depending on the initial active surface of WC, may be oxidized to WO x, whereby the rate of recombination decreases about three times. It is assumed that the oxidation of WC is due to the H 2O 2 formed as an intermediate product of the recombination of hydrogen and oxygen. Silver accelerates the decomposition of H 2O 2 and hence the use of a WC—Ag mixture as catalyst in the recombination electrodes reduces strongly the carbide corrosion.