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Title: In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide

Abstract

Graphene oxide (GO) and reduced graphene oxide (rGO) are important materials in a wide range of fields. The modified Hummers methods, for synthesizing GO, and subsequent thermal reduction to rGO, are often employed for production of rGO. However, the mechanism behinds these syntheses methods are still unclear. We present an in situ X-ray diffraction study of the synthesis of GO and thermal reduction of GO. The X-ray diffraction revealed that the Hummers method includes an intercalation state and finally formation of additional crystalline material. The formation of GO is observed during both the intercalation and the crystallization stage. During thermal reduction of GO three stages were observed: GO, a disordered stage, and the rGO stage. The appearance of these stages depends on the heating ramp. The aim of this study is to provide deeper insight into the chemical and physical processes during the syntheses. - Graphical abstract: In situ X-ray diffraction results for of the modified Hummers synthesis and the thermal reduction of graphene oxide, revealing three stages for both syntheses as well as new GO diffraction peaks and unidentified crystalline material for the Hummers synthesis and a disordered stage for the thermal reduction of graphene oxide. Display Omitted -more » Highlights: • Hummers synthesis consists of three stages: dissolution, intercalation and crystal. • GO is produced early on during the synthesis and display new diffraction peaks. • An unidentified triclinic phase is observed for the Hummers synthesis. • Thermal reduction of GO display three stages: GO, a disordered stage and rGO. • In situ XRD indicate reformation of rGO even for fast heated thermal reduction.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
22584177
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 240; Other Information: Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 77 NANOSCIENCE AND NANOTECHNOLOGY; CLATHRATES; CRYSTALLIZATION; CRYSTALS; DISSOLUTION; GRAPHENE; HEATING; OXIDES; PEAKS; POWDERS; SYNTHESIS; X RADIATION; X-RAY DIFFRACTION

Citation Formats

Storm, Mie Møller, E-mail: mmst@dtu.dk, Johnsen, Rune E., and Norby, Poul. In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide. United States: N. p., 2016. Web. doi:10.1016/J.JSSC.2016.05.019.
Storm, Mie Møller, E-mail: mmst@dtu.dk, Johnsen, Rune E., & Norby, Poul. In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide. United States. doi:10.1016/J.JSSC.2016.05.019.
Storm, Mie Møller, E-mail: mmst@dtu.dk, Johnsen, Rune E., and Norby, Poul. 2016. "In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide". United States. doi:10.1016/J.JSSC.2016.05.019.
@article{osti_22584177,
title = {In situ X-ray powder diffraction studies of the synthesis of graphene oxide and formation of reduced graphene oxide},
author = {Storm, Mie Møller, E-mail: mmst@dtu.dk and Johnsen, Rune E. and Norby, Poul},
abstractNote = {Graphene oxide (GO) and reduced graphene oxide (rGO) are important materials in a wide range of fields. The modified Hummers methods, for synthesizing GO, and subsequent thermal reduction to rGO, are often employed for production of rGO. However, the mechanism behinds these syntheses methods are still unclear. We present an in situ X-ray diffraction study of the synthesis of GO and thermal reduction of GO. The X-ray diffraction revealed that the Hummers method includes an intercalation state and finally formation of additional crystalline material. The formation of GO is observed during both the intercalation and the crystallization stage. During thermal reduction of GO three stages were observed: GO, a disordered stage, and the rGO stage. The appearance of these stages depends on the heating ramp. The aim of this study is to provide deeper insight into the chemical and physical processes during the syntheses. - Graphical abstract: In situ X-ray diffraction results for of the modified Hummers synthesis and the thermal reduction of graphene oxide, revealing three stages for both syntheses as well as new GO diffraction peaks and unidentified crystalline material for the Hummers synthesis and a disordered stage for the thermal reduction of graphene oxide. Display Omitted - Highlights: • Hummers synthesis consists of three stages: dissolution, intercalation and crystal. • GO is produced early on during the synthesis and display new diffraction peaks. • An unidentified triclinic phase is observed for the Hummers synthesis. • Thermal reduction of GO display three stages: GO, a disordered stage and rGO. • In situ XRD indicate reformation of rGO even for fast heated thermal reduction.},
doi = {10.1016/J.JSSC.2016.05.019},
journal = {Journal of Solid State Chemistry},
number = ,
volume = 240,
place = {United States},
year = 2016,
month = 8
}
  • The functionalization of graphene oxide (GO) and graphene by TiO 2 and other metal oxides has attracted considerable attention due to numerous promising applications in catalysis, energy conversion, and storage. We propose hydrogenation of this class of materials as a promising way to tune catalytic properties by altering the structural and chemical transformations that occur upon H incorporation. We also investigate the structural changes that occur during the hydrogenation process using in situ powder X-ray diffraction and pair distribution function analysis of GO–TiO 2 and TiO 2 under H 2 reduction. Sequential Rietveld refinement was employed to gain insight intomore » the evolution of crystal growth of TiO 2 nanoparticles in the presence of two-dimensional (2D) GO nanosheets. GO sheets not only significantly retarded the nucleation and growth of rutile impurities, stabilizing the anatase structure, but was also partially reduced to hydrogenated graphene by the introduction of atomic hydrogen into the honeycomb lattice. We discuss the hydrogenation processes and the resulting composite structure that occurs during the incorporation of atomic H and the dynamic structural transformations that leads to a highly active photocatalyst.« less
  • Hydrothermal conversion of zeolite Li-A(BW), LiAlSiO{sub 4}{center_dot}H{sub 2}O, into {alpha}-eucryptite, LiAlSiO{sub 4}, occurs at temperatures above 350 C. The authors report here the first in-situ study of a high-temperature hydrothermal synthesis using time-resolved power diffraction. The hydrothermal syntheses were performed in stainless steel capillaries. To maintain hydrothermal conditions, a hydraulic pressure of 2--300 atm was applied. Synchrotron X-ray radiation with energies of 35--40 keV was used in order to penetrate the steel capillaries. Room temperature Imaging Plate powder diffraction data were collected on a sample of zeolite Li-A(BW) contained in a steel capillary in an aqueous solution at 200 atm.more » pressure. With the use of a 10 min exposure, it was possible successfully to refine the crystal structure of zeolite Li-A(BW) using Rietveld refinement. Angle dispersive time-resolved in-situ powder diffraction patterns were collected using a Translating Imaging Plate (TIP) camera. Crystallization and degradation curves for the high-temperature hydrothermal conversion experiments were determined using integrated intensities of selected diffraction lines. The kinetic curves were analyzed using first-order rate expressions.« less
  • Highlights: • RGO-1 and RGO-2 were synthesized by green method using different phytoextracts. • M. indica L., S. tuberosum L. phytoextracts act as reducing and stabilizing agents. • Conjugated structure of graphene is established following partial reduction of GO. • Electrical conductivities of RGO-1 and RGO-2 are higher than GO. - Abstract: An environmentally friendly method has been applied for the preparation of reduced graphene oxide (RGO). This method was developed by using polyphenols that contained a phytoextract of Mangifera indica L. along with Solanum tuberosum L. as reducing agents since they are non-toxic and naturally available. The phytoextracts usedmore » in the production of RGO was set between 60 and 70 °C. Graphene oxide (GO) was prepared by modified Hummer’s method as reported in earlier findings. Structural and morphological studies demonstrate that the part of the oxygen functionalities in GO can be removed by following green reduction. Characterizations of the resulting product have been done by X-ray diffraction, FTIR, UV–vis and Raman spectroscopy. FESEM, TEM, EDX spectrum, TGA, DLS and Zeta potential measurements of the samples have also been carried out to study the morphological, thermal and surface charge characteristics. Electrical conductivity was also measured to check the extent of reduction of GO to RGO.« less
  • No abstract prepared.