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Title: Anomalous dielectric relaxation of water confined in graphite oxide

Nonmonotonic thermal dependence of dielectric relaxation of water has been observed in hydrated graphite oxide (GO). Graphite oxide prepared via Hummers method then imbued with specific water contents were characterized, with {sup 13}C and {sup 1}H nuclear magnetic resonance spectroscopies, X-ray photoelectron spectroscopy, ambient- and variable-temperature X-ray diffractometries, as well as thermogravimetric analysis. Pressed pellets provided with either conducting or blocking electrodes yielded dielectric loss, which was shown to originate from dielectric relaxation of the confined water. Three relaxation processes were observed in impedance spectroscopy. Our previous work has identified two different types of water in GO, namely, intercalated water and water in inter-grain voids. P{sub 1} expresses the reorientation of water confined inside inter-grain voids, and P{sub 2}, the rotation of intercalated water molecules confined in interlayers. The present work reveals a new process P{sub 3}, which also relates to intercalated water. It slows down with temperature, and this apparent anomaly is explained by the decrease in water content and consequent narrowing of interlayer spacing in graphite oxide, as confirmed by characterization techniques. The present study should contribute to our understanding of surface water dynamics.
Authors:
; ;  [1] ;  [2]
  1. National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)
  2. Department of Physics, Hong Kong Baptist University, Kowloon, Hong Kong (China)
Publication Date:
OSTI Identifier:
22492721
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 12; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON 13; CLATHRATES; DIELECTRIC MATERIALS; ELECTRODES; GRAPHITE; HUMIDITY; IMPEDANCE; LOSSES; MOLECULES; NUCLEAR MAGNETIC RESONANCE; OXIDES; PELLETS; RELAXATION; THERMAL GRAVIMETRIC ANALYSIS; WATER; X-RAY DIFFRACTION; X-RAY PHOTOELECTRON SPECTROSCOPY