Corresponding States Interpretation of Adsorption in Gate-Opening Metal-Organic Framework Cu(dhbc)2(4,4'-bpy)


The "universal adsorption theory" (UAT) extends the principle of corresponding states for gas compressibility to describe the excess density of an adsorbed phase at comparable reduced conditions. The UAT helps to describe experimental trends and provide predictive capacity for extrapolation from one adsorption isotherm to that of a different adsorbate. Here, we extend the UAT to a flexible metal-organic framework (MOF) as a function of adsorbate, temperature, and pressure. When considered via the UAT, the adsorption capacity and GO pressure of multiple gases to Cu(dhbc)2(4,4'-bpy) [H2dhbc=2,5-dihydroxybenzoic acid, bpy=bipyridine] show quantifiable trends over a considerable temperature and pressure range, despite the chemical and structural heterogeneity of the adsorbent. Exceptions include quantum gases (such as H2) and prediction of maximum capacity for large and/or polar adsorbates. A method to derive the heat of gate opening and heat of expansion from experimental trends is also presented, and the parameters can be treated as separable and independent over the temperature and pressure range studied. We demonstrate the relationship between the UAT and the common Dubinin analysis, which was not previously noted.


Chemical and Biochemical Engineering


United States. Department of Energy. Office of Energy Efficiency and Renewable Energy


This work was supported, in part, by the U.S. Department of Energy, Energy Efficiency and Renewable Energy program, Award DE-FG36-08GO18139.

Keywords and Phrases

Adsorbates; Compressibility of gases; Crystalline materials; Gas adsorption; Gases; Organometallics; 2 ,5-dihydroxybenzoic acids; Gas compressibilities; Gas separations; Gas storage; Metal organic framework; Porous coordination polymer; Structural heterogeneity; Temperature and pressures; Adsorption; adsorbent; bipyridine derivative; copper; gentisic acid; hydrogen; metal organic framework; adsorption; Article; channel gating; chemical analysis; chemical structure desorption; energy transfer; gas; pressure; priority journal; quantum chemistry; temperature

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2015 Elsevier, All rights reserved.

Publication Date

01 May 2015