Smirnov Konstantin S
Laboratoire de Spectrochimie Infrarouge et Raman, UMR 8516 CNRS - Université de Lille - Sciences et Technologies, 59655 Villeneuve d'Ascq, France.
Phys Chem Chem Phys. 2017 Jan 25;19(4):2950-2960. doi: 10.1039/c6cp06770k.
The interaction of water with the hydroxylated (010) surface of silicalite-1 was studied by classical molecular dynamics simulations. Interatomic interactions in the system were described using a set of effective potentials combining well-tested BKS and SPC models. The extended force field is shown to correctly reproduce the structural, energy, and dynamical characteristics of the silica surface OH groups. The interaction of water with the hydrophilic silanols leads to an ordering of HO molecules in the vicinity of the surface. The ordering is found to be limited to two molecular layers extending to 7 Å above the surface. Despite the hydrophobic nature of the silicalite structure and the presence of hydrophilic surface sites, water molecules are capable of penetrating the porous silicalite system, where they form an H-bonded network blocking further access to the bulk. Water uptake by the zeolite was computed to be small in the time-scale of the simulations. The vibrational dynamics of the surface OH groups and adsorbed water molecules is discussed in detail. In agreement with the results of spectroscopic experiments, water molecules in the ordered surface layer have a spectral signature different from that of molecules more distant from the surface.
通过经典分子动力学模拟研究了水与硅沸石-1的羟基化(010)表面之间的相互作用。使用一组结合了经过充分测试的BKS和SPC模型的有效势来描述系统中的原子间相互作用。结果表明，扩展力场能够正确再现二氧化硅表面羟基的结构、能量和动力学特征。水与亲水性硅醇的相互作用导致表面附近的HO分子有序排列。发现这种有序排列仅限于延伸至表面上方7 Å的两个分子层。尽管硅沸石结构具有疏水性且存在亲水性表面位点，但水分子能够穿透多孔硅沸石体系，在其中形成氢键网络，从而阻止进一步进入主体部分。在模拟的时间尺度上，计算得出沸石的吸水量很小。详细讨论了表面羟基和吸附水分子的振动动力学。与光谱实验结果一致，有序表面层中的水分子具有与远离表面的分子不同的光谱特征。
