Porous Ice Phases with VI and Distorted VII Structures Constrained in Nanoporous Silica

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• 作者：Jinlong Zhu ; Zewei Quan ; Yu-Shen Lin ; Ying-Bing Jiang ; Zhongwu Wang ; Jianzhong Zhang ; Changqing Jin ; Yusheng Zhao ; Zhenxian Liu ; C. Jeffrey Brinker ; Hongwu Xu
• 刊名：Nano Letters
• 出版年：2014
• 出版时间：November 12, 2014
• 年：2014
• 卷：14
• 期：11
• 页码：6554-6558
• 全文大小：400K
• ISSN：1530-6992

文摘

High-pressure compression of water contained in nanoporous silica allowed fabrication of novel porous ice phases as a function of pressure. The starting liquid nanoporous H₂O transformed to ice VI and VII at 1.7 and 2.5 GPa, respectively, which are 0.6 and 0.4 GPa higher than commonly accepted pressures for bulk H₂O. The continuous increase of pressure drives the formation of a tetragonally distorted VII structure with the space group I4mm, rather than a cubic Pn3m phase in bulk ice. The enhanced incompressibility of the tetragonal ice is related to the unique nanoporous configuration, and the distortion ratio c/a gradually increases with increasing pressure. The structural changes and enhanced thermodynamic stability may be interpreted by the two-dimensional distribution of silanol groups on the porous silica surfaces and the associated anisotropic interactions with H₂O at the interfaces.

Keywords:

Nanoporous ice; high pressure; DAC; SAXS; WAXS