Adsorption on a surface with varying properties

We propose a self-consistent model taking into account the variations in adsorption properties of an adsorbent surface in the process of adsorption–desorption of gas particles on it. We introduce a dimensionless coupling parameter equal to the normalized adsorption-induced activation energy for desorption due to the substrate deformation caused by the adsorption-induced force. Bistability of the system of noninteracting adparticles is established in the case when the coupling parameter is greater than a critical value and the gas concentration belongs to a certain interval. We show that the adsorption isotherms obtained within the framework of the proposed model essentially differ from the Langmuir isotherms and we show that the Zeldovich hysteresis is possible. The kinetics of the surface coverage is analyzed in detail in the overdamped approximation. We show the possibility of a ‘quasi-stationary’ state of the system due to variations in adsorption properties of the surface in adsorption–desorption.