Mechanical-pressure induced response of the MOF Al-MIL-53-TDC

Abstract

The mechanical behavior of the recently synthesized flexible metal organic framework [Al(OH)(TDC)] with the well-known MIL-53 topology, built of 2,5-thiophenedicarboxylate (TDC2−) , OH– and Al3+ ions, named Al-MIL-53-TDC, has been explored using a combination of advanced characterization tools including mercury intrusion and high-pressure synchrotron X-ray powder diffraction, supported by Density Functional Theory calculations. This hybrid porous material was shown to exhibit a pressure-induced reversible structural contraction at ∼275 MPa associated with a unit cell volume change of ∼28.1% and a hysteresis loop once the pressure is released. This leads to an unprecedented energy work of 79 J g−1 that can be stored during one compression/decompression cycle for such a class of porous solids presenting a large-pore form ↔ closed-pore form phase transition. As such Al-MIL-53-TDC is at this time the best candidate of the MIL-53’s family for a future potential application where a nano-damper is required.