Mass transfer at packed-bed, gas-evolving electrodes

Abstract

Mass transfer rates were measured for the cathodic reduction of potassium ferricyanide at a H2-evolving electrode consisting of a packed bed of spheres. Variables studied were bed height, H2 discharge rate and ferricyanide concentration. It was found that the mass transfer coefficient (K) is related to the H2 discharge rate (V) by the equation $$K = aV^{0.325} $$ Bed height and electrolyte concentration were found to have little effect on the mass transfer coefficient. A mathematical model based on the surface renewal theory was formulated to explain the mechanisms of mass transfer at gas-evolving electrodes.