Buchsteiner Alexandra, Lerf Anton, Pieper Jörg
Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109 Berlin, Germany.
J Phys Chem B. 2006 Nov 16;110(45):22328-38. doi: 10.1021/jp0641132.
Graphite oxide is an inorganic multilayer system that preserves the layered structure of graphite but not the conjugated bond structure. In the past few years, detailed studies of the static structure of graphite oxide were carried out. This was mainly done by NMR investigations and led to a new structural model of graphite oxide. The layer distance of graphite oxide increases with increasing humidity level, giving rise to different spacings of the carbon layers in the range from 6 to 12 A. As a consequence, different types of motions of water and functional groups appear. Information about the mobility of the water molecules is not yet complete but is crucial for the understanding of the structure of the carbon layers as well as the intercalation process. In this paper, the hydration- and temperature-dependent dynamic behavior of graphite oxide will be investigated by quasielastic neutron scattering using the time-of-flight spectrometer NEAT at the Hahn-Meitner-Institut Berlin. The character of the embedded water does not change over a wide range of hydration levels. Especially the interlayer water remains tightly bound and does not show any translational motion. In samples with excess water, however, the water is also distributed in noninterlayer voids, leading to the observation of additional motions of bulklike or confined water. The dynamic behavior of hydrated graphite oxide can be described by a consistent model that combines two two-site jump motions for the motions of the water molecules and the motions of OH groups.
氧化石墨烯是一种无机多层体系，它保留了石墨的层状结构，但没有共轭键结构。在过去几年中，对氧化石墨烯的静态结构进行了详细研究。这主要是通过核磁共振研究完成的，并得出了氧化石墨烯的新结构模型。氧化石墨烯的层间距随湿度水平的增加而增大，导致碳层间距在6至12埃范围内有所不同。因此，出现了水和官能团的不同类型运动。关于水分子迁移率的信息尚不完整，但对于理解碳层结构以及插层过程至关重要。在本文中，将使用柏林哈恩-迈特纳研究所的飞行时间光谱仪NEAT，通过准弹性中子散射研究氧化石墨烯的水合和温度依赖性动态行为。在很宽的水合水平范围内，嵌入水的性质不会改变。特别是层间水仍然紧密结合，没有任何平移运动。然而，在含水量过多的样品中，水也分布在非层间空隙中，导致观察到块状或受限水的额外运动。水合氧化石墨烯的动态行为可以用一个一致的模型来描述，该模型结合了水分子运动和羟基运动的两个双位点跳跃运动。
