NEAR-SURFACE KINETICS OF HYDROGEN PERMEATION INTO IRON AND THE MECHANISM OF CATHODIC HYDROGEN EVOLUTION IN ALKALINE-SOLUTIONS - MECHANISM OF THE ELEMENTARY ACT OF THE ELECTROLYTIC HYDROGEN PERMEATION INTO IRON

Using the electrochemical diffusion method, we studied the diffusion o f atomic electrolytic hydrogen through iron membranes under the condit ions of hydrogen cathodic evolution from alkaline solutions including solutions with inhibitors and promoters of hydrogen absorption. It was shown that the kinetic permeation current, which characterizes the ra te of hydrogen absorption from the surface into the subsurface layer o f iron, is an exponentially increasing function of the hydrogen-evolut ion overpotential. The constant of hydrogen desorption from the iron s ubsurface layer to the surface does not depend on the overpotential of the hydrogen evolution in a wide range of overpotential values. In co ntrast to the literature, these results show that the transition of th e hydrogen atoms from the surface to the subsurface layer can really b e described by the reversible reaction of the first order: H(ads) reve rsible H(abs).