Effect of sodium dodecyl sulfate on the rate of hydrogen evolution at a cathode

The effect of H(2) evolution on the mass-transfer coefficient of cathode reduction of potassium ferricyanide at a mercury cathode was studied with the aim of (i) comparing the mass transfer behavior at a Hg cathode with that at solid electrodes under gas-evolving conditions and (ii) testing the effect of anionic surface-active agent on the mass transfer behavior of an H(2)-evolving Hg cathode. It is found that the mass transfer coefficient at the Hg cathode was much higher than the value at a solid cathode. The mass transfer coefficient at H(2)-evolving Hg was found to decrease in the presence of sodium dodecyl sulfate (SDS) surfactant by an amount ranging from 58.8 to 76%, depending on the H(2) discharge rate and the SDS concentrations.