This leads to the following hypothesis: In a step like the classical Volmer step, atomic hydrogen is formed on the surface (Eq. 54a), while in a step like that of the classical Tafel step, hydrogen atoms combine to form molecular hydrogen and leave the surface (Eq. 54b), connected through the steady state condition (Eq. 54c). Analyzing the Tafel slope in the HER branch, one finds that the interaction function Λ(𝜃) leads to a Tafel slope exceeding 120 mV/decade (Eq. 54d).