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Synthesis of graphene from natural and industrial carbonaceous wastes
, Article RSC Advances ; Vol. 4, issue. 39 , 2014 , p. 20441-20448 ; Bijanzad, K ; Mirsepah, A ; Sharif University of Technology
Abstract
Graphene oxide (GO) and reduced graphene oxide (rGO) sheets have usually been synthesized through Hummers' method by using highly pure graphite (HPG) as the main starting material. However, HPG can be relatively expensive for mass production of high-quality graphene. In this work, a general method for synthesis of high-quality GO and rGO sheets from various natural and industrial carbonaceous wastes such as vegetation wastes (wood, leaf, bagasse, and fruit wastes), animal wastes (bone and cow dung), a semi-industrial waste (newspaper), and an industrial waste (soot powders produced in exhaust of diesel vehicles) was developed. Based on atomic force microscopy, Raman spectroscopy, X-ray...
Hydrogen-rich water for green reduction of graphene oxide suspensions
, Article International Journal of Hydrogen Energy ; Volume 40, Issue 16 , 2015 , Pages 5553-5560 ; 03603199 (ISSN) ; Azimirad, R ; Gholizadeh, H. T ; Ghorbani, F ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Abstract H2-rich water as a green antioxidant was applied for deoxygenation of graphene oxide (GO) suspensions. The ability of H2-rich water for deoxygenation of GO sheets was found comparable to the ability of hydrazine (as a standard and powerful reductant), using X-ray photoelectron spectroscopy. In fact, the O/C ratio of GO sheets could be reduced from 0.51 to 0.21 and 0.16 by H2-rich water and hydrazine, respectively. More importantly, while C-N bond formation is one of the side effects of GO reduction by hydrazine, no chemical C-N bond was found on the H2-water-reduced GO (rGO) sheets. This also resulted in a better restoration of the graphitic structure of the H2-water-rGO, as...
Rolled graphene oxide foams as three-dimensional scaffolds for growth of neural fibers using electrical stimulation of stem cells
, Article Carbon ; Volume 97 , 2016 , Pages 71-77 ; 00086223 (ISSN) ; Ghaderi, E ; Shirazian, S. A ; Rahighi, R ; Sharif University of Technology
Elsevier Ltd
Abstract
Graphene oxide foam (GOF) layers with thicknesses of ∼15-50 μm and density of ∼10 graphene oxide (GO) sheets/μm were fabricated by precipitation of chemically exfoliated GO sheets in an aqueous suspension at ∼80 °C under UV irradiation. Then, rolled GOFs with desirable scales were developed as electrically conductive 3D-scaffolds and applied in directional growth of neural fibers, through differentiation of human neural stem cells (hNSCs) into neurons under an electrical stimulation. X-ray photoelectron spectroscopy indicated that the UV irradiation resulted in partial deoxygenation of the layers. Scanning electron microscopy and Raman spectroscopy confirmed the presence of multilayer GO...