SOME ABNORMAL HYDROGEN ELECTRODE REACTIONS

Abstract

A brief account is given of experiments in which gold electrodes, as a result of thermal deactivation in hydrogen, change from a state in which their behavior in relation to the hydrogen evolution reaction is normal to a state characterized by high positive rest potentials, greatly enhanced overpotentials which increase progressively during current flow, and which decay slowly on open circuit, generating potential–time curves which resemble desorption isotherms.Conclusions based on these phenomena are supported by the results of experiments with poisoned platinum electrodes, which not only behave similarly but are also shown to retain reducing power for a limited time on open circuit.It is suggested that electrodeposited hydrogen atoms may sometimes evaporate from an electrode into solution by a mechanism involving the participation of molecule-ions. A recent theoretical treatment of hydrogen overpotential can be extended to allow for the occurrence of such a final reaction step.