探索分子大小和框架功能化对金属有机框架中的运输的影响,使用脉冲场梯度核磁共振
Shima Zainal1, Ahmed Alsudani2, Ralph W Adams2
1Department of Chemical Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK. carmine.dagostino@manchester.ac.uk.
Physical chemistry chemical physics : PCCP
|June 24, 2024
概括
脉冲场梯度核磁共振 (PFG NMR) 揭示了分子大小如何影响金属有机框架 (MOF) 中的扩散. 连接器功能和孔隙结构显著影响这些材料内的分子运输.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 物理化学 物理化学
背景情况:
- 分子运输对于金属有机框架 (MOFs) 的应用,如分离和催化,至关重要.
- 了解扩散机制及其与MOF结构的关系是具有挑战性的和未被充分探索的.
- 孔隙结构和链接器动力学等MOF特征对分子运输具有重要影响.
研究的目的:
- 研究UiO-66 MOF及其衍生物 (UiO-66NH2和UiO-66Br) 中的分子扩散机制.
- 探索探针分子大小对不同MOF孔环境中的扩散通路的影响.
- 阐明链接器功能化在调节分子运输和MOF特性中的作用.
主要方法:
- 使用脉冲场梯度核磁共振 (PFG NMR) 光谱.
- 采用了不同动力直径的各种探头分子 (水,烯,TIPB).
- 分析了PFG NMR日志衰减图,以区分在晶体间和晶体内空间中的扩散.
主要成果:
- 对小分子的非线性PFG NMR图表显示了双重扩散率:在晶体间空间更快,在MOF框架内更慢.
- 对大分子 (TIPB) 的线性PFGNMR图表表明,扩散仅在晶体间空间.
- 显示链接器功能化通过影响分子内相互作用和孔隙可访问性来影响分子扩散.
结论:
- MOF 孔径大小,结构,链接器功能化和分子相互作用共同控制探针分子扩散.
- PFG NMR是一种强大的技术,可以帮助我们更好地理解MOF中的质量运输.
- 结果为优化基于MOF的材料的各种应用提供了洞察力.
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