Structural Transitions in MIL-53 (Cr): View from Outside and Inside
Structural Transitions in MIL-53 (Cr): View from Outside and Inside
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DOI：
10.1021/la200094x
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发表时间：
2011-04-19
期刊：
影响因子：
3.9
通讯作者：
Denoyel, Renaud
中科院分区：
文献类型：
--
作者：
Neimark, Alexander V.;Coudert, Francois-Xavier;Denoyel, Renaud
我们提出了一个统一的热力学描述的呼吸之间的过渡大孔（LP）和窄孔（NP）相的MIL-53（Cr）的过程中观察到的客体分子的吸附和机械压缩的压汞法。通过重新审视最近的实验数据汞侵入和原位XRD在CO2吸附过程中，我们表明，由客体分子，这是诱导呼吸过渡所需的孔内施加的吸附应力的大小，对应于从外部施加的外部压力的大小，导致LP和NP相之间的各自的转换。我们表明，当刺激施加到呼吸MIL-53型的MOFs这些材料表现出小的可逆的弹性变形的LP和NP阶段的顺序为2- 4%，而呼吸过渡与不可逆的塑性变形，导致类似的样品体积的40%的变化和明显的滞后。这些结果揭示了MIL-53（铬）和其他软多孔晶体（SPC）的结构转变的细节。
We present a unified thermodynamic description of the breathing transitions between large pore (lp) and narrow pore (np) phases of MIL-53 (Cr) observed during the adsorption of guest molecules and the mechanical compression in the process of mercury porosimetry. By revisiting recent experimental data on mercury intrusion and in situ XRD during CO2 adsorption, we demonstrate that the magnitude of the adsorption stress exerted inside the pores by guest molecules, which is required for inducing the breathing transition, corresponds to the magnitude of the external pressure applied from the outside that causes the respective transformation between lP and np phases. We show that, when a stimulus is applied to breathing MOFs of MIL-53 type these materials exhibit small reversible elastic deformations of lp and np phases of the order of 2-4%, while the breathing transition is associated with irreversible plastic deformation that leads up to similar to 40% change of the sample volume and a pronounced hysteresis. These results shed light on the specifics of the structural transformations in MIL-53 (Cr) and other soft porous crystals (SPC).