Ice II-like Monolayer Ice Grown on Graphite Surface
Ice II-like Monolayer Ice Grown on Graphite Surface
复制标题
石墨表面生长的类冰II单层冰
DOI：
10.1021/acs.jpcc.9b04310
复制
发表时间：
2019
影响因子：
3.7
通讯作者：
Wang Jun Zhong
中科院分区：
文献类型：
--
作者：
Wang Ya Ru;Xu Ji Yu;Ma Chao Ke;Shi Ming Xia;Tu Yu Bing;Sun Kai;Meng S;Wang Jun Zhong
固体表面上的水对于广泛的科学和技术过程是必不可少的。先前的研究表明，金属表面的水分子通常形成具有蜂窝状氢键网络的层状结构，类似于六边形冰Ih的基面。本文报道了一种在低温条件下在石墨表面生长的新型单层冰。高分辨率STM图像显示，单层冰由循环水六聚体组成，没有共享边缘。此外，单层冰相对于石墨晶格表现出多种取向，导致各种云纹图案。第一性原理计算表明，云纹上部结构包含倾斜和平面的水六聚体，与STM图像中观察到的马蹄形和扁平的水环相对应。单层冰内的所有水分子都被四个氢键饱和，层内的强键作用使单层冰具有很高的稳定性。
Water on solid surfaces is essential for a wide range of scientific and technological processes. Previous studies reveal that water molecules on metal surfaces usually form layered structures with a honeycomb hydrogen-bond network, similar to the basal plane of hexagonal ice Ih. Here we report a new type of monolayer ice grown on graphite surface at low temperature with subsequent annealing. High-resolution STM images reveal that the monolayer ice is composed of cyclic water hexamers without sharing edges. Moreover, the monolayer ice exhibits multiple orientations relative to the graphite lattices, resulting in various moire patterns. First-principles calculations reveal that the moire superstructures contain both tilted and planar water hexamers, corresponding to the horseshoe-like and flat water rings observed in the STM images. All water molecules within the monolayer are saturated by four hydrogen bonds, and the strong intralayer bonding gives rise to a high stability of the monolayer ice.