Abstract
Modeling of absorption and desorption isotherms of hydrogen on LaNi4.85Al0.15 alloy at 298 K, 303 K and 313 K has been achieved through the use of grand canonical ensemble in statistical physics. In fact, a monolayer model with two levels of energy has been adopted to better fit the experimental data. Besides, six physicochemical parameters have been used to better describe the absorption and desorption processes from the point of view of alpha and beta phases. These parameters are divided into two types. The first type of parameters contains four main parameters, namely the number of atoms per site, n(alpha) and n(beta), and the densities of hydrogen receptor sites N-m alpha as well as N-m beta. The second type of parameters are mainly the two energetic parameters P-alpha and P-beta which respectively refer to the pressures at half saturations for the a phase and the beta phase. Thanks to these steric and energetic parameters, we could compare the absorption and desorption processes to highlight the evolution of these parameters during hysteresis encountered in the desorption isotherms. (C) 2016 Elsevier B.V. All rights reserved.