On the supersaturation of gas in the concentration boundary layer of gas evolving electrodes

Gas concentrations in the vicinity of gas evolving electrodes obtained from application of a galvanostatic potential—transient method and from concentration overpotential are opposed to concentrations obtained by different and independent methods: by evaluation of bubble growth data and of data for the fractional gas coverage of the electrode surface. All experimental values are taken from literature. Discussion of the concentration distribution in the boundary layer of gas evolving electrodes evidences the necessity to distinguish clearly between a supersaturation decisive in nucleation and a separate supersaturation decisive in bubble growth.