HYDROGEN EVOLUTION REACTION AT MERCURY AND AMALGAM ELECTRODES IN THE PRESENCE OF DIPHENYLAMINE.

The hydrogen evolution reaction of mercury and indium amalgam electrodes follows Volmer Heyrovsky mechanism. This reaction is accelerated in presence of sulfur containing compounds and diphenyl amine. The accelerating effect of diphenyl amine is larger near PZC and this is due to the adsorption of protonated diphenyl amine. In case of indium amalgam electrodes, the acceleration of the h. e. r. reaction is similar to that at mercury elctrodes because it occurs nearer the PZC.