The Temkin isotherm takes into account surface heterogeneity . Its equation is based on the assumption of the heterogeneity of the surface energy distribution and linear decrease of the adsorption heat with the increase in the surface coverage by the inhibitor. The difference between the maximum and minimum adsorption heat is described by the parameter f, which is taken to be positive and increases with an increase in the heterogeneity of the surface. Therefore, in the Temkin model, it is assumed that adsorption occurs on the energy-favorable surface locations and can be expressed as: