Water nanodroplets confined in zeolite pores
Water nanodroplets confined in zeolite pores
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DOI：
10.1039/b804992k
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发表时间：
2009-01-01
影响因子：
3.4
通讯作者：
Boutin, Anne
中科院分区：
文献类型：
--
作者：
Coudert, Francois-Xavier;Cailliez, Fabien;Boutin, Anne
我们提供了一个全面的描述的行为的nanodroplet的20个水分子限制在一系列的3D连接的具有不同酸度的同构沸石的孔，通过分子模拟。使用经典原子间力场和第一性原理Car-Parrinello分子动力学的巨正则蒙特卡罗模拟都被用来通过计算其性质范围，前沿热力学量到电子性质如其偶极矩，包括结构和动力学信息来描述承压水的行为。从热力学角度，我们已经确定了全硅沸石的疏水性，和阳离子沸石的亲水性，在第一种情况下的缩合转变被证明是一级的。此外。对水的动力学和电子性质的深入分析表明，疏水沸石中的水表现为试图将其氢键网络闭合到其自身上的纳米液滴，其中几乎没有短寿命的悬挂油基团。而亲水沸石中的水“打开”与沸石氧原子形成弱氢键。最后，研究了承压水的偶极矩，讨论了水的自极化和沸石电场的贡献。
We provide a comprehensive depiction of the behaviour of a nanodroplet of 20 water molecules confined in the pores of a series of 3D-connected isostructural zeolites with varying acidity, by means of molecular simulations. Both grand canonical Monte Carlo simulations using classical interatomic forcefields and first-principles Car-Parrinello molecular dynamics were used in order to characterise the behaviour of confined water by computing it range of properties, front thermodynamic quantities to electronic properties such its dipole moment, including structural and dynamical information. From the thermodynamic point of vie x, we have identified the all-silica zeolite as hydrophobic, and the cationic zeolites its hydrophilic; the condensation transition in the first case was demonstrated to be of first order. Furthermore. in-depth analysis of the dynamical and electronic properties of water showed that water in the hydrophobic zeolite behaves as a nanodroplet trying to close its hydrogen-bond network onto itself, with I few short-lived dangling Oil groups. while water in hydrophilic zeolites "opens up" to form weak hydrogen bonds with the zeolite oxygen atoms. Finally, the dipole moment of confined Water is studied and the contributions of water self-polarisation and the zeolite electric field are discussed.