Control of hysteretic sorption of flexible MOF for practical acetylene safe storage

Abstract Safe managing and storage of explosive gas, such as acetylene, is essential for industries. The practical pressure and temperature regime is quite narrow for acetylene, and the optimization by complete release of saturated gas remains challenging to control. Here, a novel approach to narrow the pressure range of gas introduction and release for the storage of unstable and pressure-sensitive gas substance is reported. Flexible metal–organic frameworks (MOFs) are expected to be an excellent storage adsorbent owing to their gated adsorption/desorption behavior. However, developing such a system in a practical and narrow pressure range remains difficult. Here, we demonstrate that the gate-opening and closing pressures of a solid solution type based on interpenetrated MOF-508 can be optimized by tuning the deformation energy of the framework and the energy of host–guest interactions. These energies were adjusted by changing the functional group on the MOF ligands and its ratio in the mixed-ligand system. The filling and release of acetylene in the practical pressure regions of up to 180 kPa leads to an on-demand porous material for acetylene storage with an usable volumetric capacity of 106 v/v under mild temperature (273–298 K) and pressure (70–120 kPa).