TITLE:
Adsorption Enthalpy Calculations of Hydrogen Adsorption at Ambient Temperature and Pressures Exceeding 300 bar
AUTHORS:
Matthew Beckner, Anne Dailly
KEYWORDS:
Ambient Temperature Hydrogen Storage; Metal-Organic Frameworks; Activated Carbon; Adsorption Enthalpy
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.4 No.10C,
October
30,
2013
ABSTRACT: Hydrogen adsorption isotherms were measured at ambient temperature to pressures exceeding 300 bar for three benchmark adsorbents: two metal-organic frameworks, Cu3(btc)2 (btc = 1,3,5-benzenetricarboxylate) and Zn4O(btb)2 (btb = 1,3,5-benzenetribenzoate), and the activated carbon MSC-30. The Dubinin-Astakhov model was applied to calculated absolute adsorption isotherms as a function of the fugacity to determine the adsorption enthalpy at ambient temperature. Comparisons of the calculated enthalpies and the surface excess concentration (excess adsorption per square meter of surface) show that Zn4O(btb)2 has an adsorption enthalpy comparable to MSC-30, but that the spacing between adsorbed molecules is much larger.