Hysteretic Adsorption and Desorption of Hydrogen by Nanoporous Metal-Organic Frameworks

Abstract

Adsorption and desorption of hydrogen from nanoporous materials, such as activated carbon, is usually fully reversible. We have prepared nanoporous metal-organic framework materials with flexible linkers in which the pore openings, as characterized in the static structures, appear to be too small to allow H 2 to pass. We observe hysteresis in their adsorption and desorption kinetics above the supercritical temperature of H 2 that reflects the dynamical opening of the “windows” between pores. This behavior would allow H 2 to be adsorbed at high pressures but stored at lower pressures.