The Adsorption of Hydrogen on Tungsten¹

Statistical Mechanical Study on the Freundlich Isotherm Equation

“…Differentiating Eq. [2] with respect to coverage (), we have dw/d ϭ b(1 Ϫ ln )/ 2 , where b Ͼ 0 (as was assigned in the text), and ln Ͻ 0 (due to 1 Ϲ Ϲ 2 with 0 Ͻ 1 Ͻ 1 and 0 Ͻ 2 Ͻ 1). This equation leads to the conclusion that dw/d Ͼ 0, namely the w increases with increasing coverage ().…”

“…Besides, the above conclusion can intuitively be obtained from the graphical presentation of Eq. [2] as the w Ϫ plot, which is composed of its components, namely the 1/ Ϫ plot and the ln Ϫ plot. Here these plots are omitted due to space considerations.…”

“…Substituting Eqs. [2] and [3] into Eq. [1], we obtain the mean of the lateral interaction energy between the N A adsorbed molecules on N S adsorption sites (U )…”

“…Furthermore, Hayward and Trapnell found that the product of the inverse slope of a log-log isotherm and temperature (nT) decreases linearly with increasing temperature for the chemisorption of hydrogen on tungsten powder (12), studied by Frankenberg (2), and that of nitrogen on tungsten powder (12), studied by Davis (3). (The adsorption data of these chemisorptions are given in Table 1 and Table 2, respectively.…”

“…The originally empirical Freundlich isotherm equation (1) has been found to be obeyed by many experimental data of adsorption, some of which are of significance (2)(3)(4)(5). Regardless of its success in the experimental aspect, the Freundlich isotherm equation is far from being theoretically clear (6 -10).…”