Water Capture Mechanisms at Zeolitic Imidazolate Framework Interfaces
Water Capture Mechanisms at Zeolitic Imidazolate Framework Interfaces
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DOI：
10.1021/jacs.1c09097
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发表时间：
2021-12-08
影响因子：
15
通讯作者：
Xiong, Wei
中科院分区：
文献类型：
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作者：
Wagner, Jackson C.;Hunter, Kelly M.;Xiong, Wei
利用1微米空间分辨率的振动和频产生光谱(VSFG)和最新的分子动力学(MD)模拟，通过区分水簇合物和中心孔填充步骤，揭示了分子筛咪唑骨架ZIF-90的捕水机理。通过VSFG和IR光谱的线形比较、VSFG强度与相对湿度的关系以及基于MB-POL的分子动力学模拟，我们发现水在每个孔内几乎同时发生聚集和中心孔填充，水依次填充其他孔。非线性光学与MD模拟的结合为孔隙填充机制提供了关键的力学见解，并表明氢键的相对强度决定了吸水机制。这种分子水平上的详细机理可以为合理优化集水用金属有机骨架提供依据。
Water capture mechanisms of zeolitic imidazolate framework ZIF-90 are revealed by differentiating the water clustering and the center pore filling step, using vibrational sum-frequency generation spectroscopy (VSFG) at a one-micron spatial resolution and state-of-the-art molecular dynamics (MD) simulations. Through spectral line shape comparison between VSFG and IR spectra, the relative humidity dependence of VSFG intensity, and MD simulations, based on MB-pol, we found water clustering and center pore filling happen nearly simultaneously within each pore, with water filling the other pores sequentially. The integration of nonlinear optics with MD simulations provides critical mechanistic insights into the pore filling mechanism and suggests that the relative strength of the hydrogen bonds governs the water uptake mechanisms. This molecular-level detailed mechanism can inform the rational optimization of metal-organic frameworks for water harvesting.