通过NMR测量完全吸附同热量
João Marreiros1, Rodrigo de Oliveira-Silva1, Paul Iacomi2
1cMACS, Department of Microbial and Molecular Systems (M2S), KU Leuven, 3001 Leuven, Belgium.
Journal of the American Chemical Society
|May 27, 2021
概括
这项研究引入了NMR放松,这是通过测量吸附等热量和局部动态来表征多孔材料的新技术. 它提供了对金属有机框架 (MOF) 内客分子相互作用的更深入的见解.
科学领域:
- 材料科学
- 物理化学
- 核磁共振光谱学
背景情况:
- 物理吸附是用于描述多孔材料的标准方法,通过平衡压力测量提供纹理信息和吸附亲和力.
- 现有的方法主要提供宏观纹理数据,对孔内的局部分子动力学和相互作用的洞察力有限.
研究的目的:
- 证明低磁场核磁共振 (NMR) 测量完全吸附等温的能力.
- 展示使用NMR放松的吸附探头分子的选择性测量如何为局部动力学提供先进的洞察力.
- 在各种微孔金属有机框架 (MOF) 上验证NMR放松技术.
主要方法:
- 开发和应用一种称为"NMR放松"的低场NMR技术.
- 从吸附探头分子中选择性测量1H旋转,将它们与蒸汽相分子区分开来.
- 在ZIF-8,UIO-66和MIL-53金属有机框架中对甲醇吸附的应用
主要成果:
- 通过NMR放松,成功测量了研究的MOF的完全吸附等温度.
- 在ZIF-8中对甲醇吸附的分析显示出不同的客分子群体,包括结合到缺陷部位的和分子.
- 对UiO-66 ((Zr) 实现了连续的孔隙填充和精确的孔隙拓测定.
- 在MIL-53 ((Al) 中的结构阶段过渡被准确地检测出来,并与特定的二次物种种群相关联.
结论:
- 核磁共振放松是一种强大的双重方法,将吸附等温测量与详细的局部动态信息相结合.
- 这项技术为MOF等多孔材料中的客宿主相互作用,分子聚类和结构动态提供了前所未有的见解.
- 与传统的物理吸收技术相比,NMR放松技术在全面的材料表征方面具有显著的进步.
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