Synthesis of Few-layer Graphene Sheets via Chemical and Thermal Reduction of Graphite Oxide

Few-layer graphene sheets were produced from graphite oxide (GO) chemical and thermal reduction. For the chemical reduction of GO as reducing agents were used hydrazine hydrate, hydroxylammonium chloride, sodium borohydride and sodium sulfite. The reduced material was characterized by elemental analysis, thermo-gravimetric analysis, scanning electron microscopy, X-ray diffraction, Fourier transform infrared and Raman spectroscopy. A comparison of the deoxygenation efficiency of graphene oxide suspension by different method or reductants has been made, revealing that the highest degree of reduction was achieved by thermal reduction and using hydrazine hydrate and hydroxylammonium chloride as a reducing agents. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3506

Preparation of Amino-Functionalized Graphene Sheets and their Conductive Properties

Amino-functionalized graphene sheets were prepared through chemical reduction by hydrazine hy-drate, amination or amidation of graphite oxide. For amination of graphite oxide were used polyamine such as ethylenediamine, diethylenetriamine and triethylenetetramine. Addition of amine groups to graphene is identified by Fourier transform infrared spectroscopy, Raman spectroscopy, elemental analysis and ther-mogravimetry. Scanning electron microscopy data indicate that the organic amine is not only as nitrogen sources to obtain the nitrogen-doped graphene but also as an important modification to control the assem-bly of graphene sheets in the 3D structures. The electrical conductivity of the materials obtained by amina-tion and amidation of graphene is much smaller than that of reduced graphite oxide. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3563

Pt supported on reduced graphite oxide catalysts for H2 activation

Platinum catalysts of H2 activation with average size ≤2.0 nm were prepared in a base of reduction conversion of graphene oxide. A low few-layered carbon nanomaterial was prepared by thermoexpansion and annealing of graphene oxide. The uniformly dispersed Pt nanoparticles were supported on two-dimension graphene flat material by the use of pyridine or polyethyleneimine in alkaline (pH10) media as chelating agent modificating both metal precursor H2PtCl6 and support. Vacancies in carbon material formed as a result of thermoexpansion and annealing of graphite oxide probablly serve as anchor groups in platinum supporting. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3557

Platinum Nanoparticles Supported on Reduced Graphite Oxide as Hydrogenation Catalyst

Platinum nanoparticles supported on reduced graphite oxide are produced by reduction of a slurry including graphite oxide and H2PtCl6·xH2O, and pyridine as modifying agent. Four compounds as a formation formateion decene-1 and nitrobenzene hydrogenation at hydrogen atmospheric pressure and 45°C. In the result of reduction Pt4+ is converted to Pt metal and graphite oxide loses of oxygen. The symbasis Pt loading with C/O ratio is observed. Compositions Pt - reduced graphite oxide catalyze the hudrogenation of decene-1 and nitrobenzene in a solution. The greatest activity is shown composition reduced by sodium borohydride with the particle size of 2.0 nm, however it is substantially lower than it for Pt/fullerene black catalyst. Some inhibiton of hydrogenation by incompletely reduced graphite oxide is shown. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3505

Electronic structure of fluorinated multiwalled carbon nanotubes studied using x ray absorption and photoelectron spectroscopy

This paper presents the results of combined investigation of the chemical bond formation in fluorinated multiwalled carbon nanotubes (MWCNTs) with different fluorine contents (10-55 wt %) and reference compounds (highly oriented pyrolytic graphite crystals and "white" graphite fluoride) using x-ray absorption and photoelectron spectroscopy at C 1s and F 1s thresholds. Measurements were performed at BESSY II (Berlin, Germany) and MAX-laboratory (Lund, Sweden). The analysis of the soft x-ray absorption and photoelectron spectra points to the formation of covalent chemical bonding between fluorine and carbon atoms in the fluorinated nanotubes. It was established that within the probing depth (similar to 15 nm) of carbon nanotubes, the process of fluorination runs uniformly and does not depend on the fluorine concentration. In this case, fluorine atoms interact with MWCNTs through the covalent attachment of fluorine atoms to graphene layers of the graphite skeleton (phase 1) and this bonding is accompanied by a change in the hybridization of the 2s and 2p valence electron states of the carbon atom from the trigonal (sp(2)) to tetrahedral (sp(3)) hybridization and by a large electron transfer between carbon an fluorine atoms. In the MWCNT near-surface region the second fluorine-carbon phase with weak electron transfer is formed; it is located mainly within two or three upper graphene monolayers, and its contribution becomes much poorer as the probing depth of fluorinated multiwalled carbon nanotubes (F-MWCNTs) increases. The defluorination process of F-MWCNTs on thermal annealing has been investigated. The conclusion has been made that F-MWCNT defluorination without destruction of graphene layers is possible

Improving the quality of 20Kh2N4A structural CrNi steel by plasma slag remelting under fluxes of the CaF2-CaO-Al2O3 system containing oxides and fluorides of rare earth metals

13.00; Translated from Ukranian (Probl. Spetsial. Elektrometall. 1986 v. 2(3) p. 68-71)SIGLEAvailable from British Library Document Supply Centre- DSC:9023.19(VR--3666)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo