Galvanostatic desorption of hydrogen from palladium layers—I. Theory

Abstract

The theory of the galvanostatic desorption of hydrogen held in a finite palladium layer (thickness, l ∼ 10 −3−10 −2 cm), in a thin palladium layer (thickness, λ ∼ 10 −6−10 −5 cm) and in a composite finite layer of a non-noble metal protected with a thin palladium layer is developed. The diffusion equations are solved by the Laplace transform and their solutions in term of the concentration of dissolved N i and weakly adsorbed N w hydrogen are given. Further the Iτ-functions are estimated for small values of the current, which allows the calculation of the characteristic parameters both of the metallic layer and of the partial steps involved, ie the diffusion and the transfer. The transient overpotentials occurring during the electrochemical desorption for a reversible and an irreversible oxidation step are also calculated.