The Concentration of Molecular Hydrogen on the Platinum Cathode

Abstract

Abstract The concentration of molecular hydrogen in the vicinity of the bright platinum cathode during electrolysis was determined as a function of current density by means of two different methods, the potential-time curve on the reversal of current from cathodic to anodic, and the concentration overpotential obtained by extrapolating the decay curve of the overpotential to zero time, free from other overpotentials. The agreement between the results for the concentration derived from the potential-time curve and from the concentration overpotential was satisfactory. It was found that the concentration of hydrogen increased with the increasing ik value and approached a limiting value of 11.6×10−2 mol./l. for cathodic currents exceeding about ik=300 mamp./cm2.