Adsorption Contraction Mechanics: Understanding Breathing Energetics in Isoreticular Metal-Organic Frameworks

作者：Krause Simon; Evans Jack D; Bon Volodymyr; Senkovska Irena; Ehrling Sebastian; Stoeck Ulrich; Yot Pascal G; Iacomi Paul; Llewellyn Philip; Maurin Guillaume; Coudert Francois Xavier; Kaskel Stefan^*

来源：Journal of Physical Chemistry C, 2018, 122(33): 19171-19179.

DOI：10.1021/acs.jpcc.8b04549

A highly porous metal-organic framework DUT-48, isoreticular to DUT-49, is reported with a high surface area of 4560 m(2).g(-1) and methane storage capacity up to 0.27 g.g(-1) (164 cm(3).cm(-3)) at 6.S MPa and 298 K. The flexibility of DUT-48 and DUT-49 under external and internal (adsorption-induced) pressure is analyzed and rationalized using a combination of advanced experimental and computational techniques. While both networks undergo a contraction by mechanical pressure, only DUT-49 shows adsorption induced structural transitions and negative gas adsorption of n-butane and nitrogen. This adsorption behavior was analyzed by microcalorimetry measurements and molecular simulations to provide an explanation for the lack of adsorption-induced breathing in DUT-48. It was revealed that for DUT-48, a significantly lower adsorption enthalpy difference and a higher framework stiffness prevent adsorption-induced structural transitions and negative gas adsorption. The mechanical behavior of both DUT-48 and DUT-49 was further analyzed by mercury porosimetry experiments and molecular simulations. Both materials exhibit large volume changes under hydrostatic compression, demonstrating noteworthy potential as shock absorbers with unprecedented high work energies.

• 出版日期2018-8-23