Optimizing Acetylene Sorption through Induced-fit Transformations in a Chemically Stable Microporous Framework.

Abstract

Developing practical storage technologies for acetylene (C2 H2 ) is important but challenging because C2 H2 is useful but explosive. Here, a novel metal-organic framework (MOF) (FJI-H36) with adaptive channels was prepared. It can effectively capture C2 H2 (159.9 cm3 cm-3 ) at 1 atm and 298 K, possessing a record-high storage density (561 g L-1 ) but a very low adsorption enthalpy (28 kJ mol-1 ) among all the reported MOFs. Structural analyses show that such excellent adsorption performance comes from the synergism of active sites, flexible framework, and matched pores; where the adsorbed-C2 H2 can drive FJI-H36 to undergo induced-fit transformations step by step, including deformation/reconstruction of channels, contraction of pores, and transformation of active sites, finally leading to dense packing of C2 H2 . Moreover, FJI-H36 has excellent chemical stability and recyclability, and can be prepared on a large scale, enabling it as a practical adsorbent for C2 H2 . This will provide a useful strategy for developing practical and efficient adsorbents for C2 H2 storage.