scholarly journals Tuning the Nature of N-Based Groups From N-Containing Reduced Graphene Oxide: Enhanced Thermal Stability Using Post-Synthesis Treatments

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1451
Author(s):  
Stefania Sandoval ◽  
Gerard Tobias
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Structural Modifications ◽  
Reduced Graphene ◽  
Wide Range ◽  
Graphene Derivatives ◽  
N Doping ◽  
Post Synthesis ◽  
Pyridinic N

The synthesis of N-containing graphene derivatives by functionalization and doping of graphene oxide (GO) has been widely reported as an alternative to tune both their chemical and physical properties. These materials are of interest for a wide range of applications, including biomedicine, sensors, energy, and catalysis, to name some. Understanding the role of the nature, reactivity, concentration, and distribution of the N-based species, would pave the way towards the design of synthetic routes to obtain improved materials for specific applications. The N-groups can be present either as aliphatic fractions (amides and amines) or becoming part of the planar conjugated lattice (N-doping). Here, we have modified the distribution of N-based moieties present in N-containing RGO samples (prepared by ammonolysis of GO) and evaluated the role of the concentration and nature of the species in the thermal stability of the materials once thermally annealed (500–1050 °C) under inert environments. After these post-synthesis treatments, samples underwent marked structural modifications that include the elimination and/or transformation of N-containing fractions, which might account for the observed enhanced thermal stability. It is remarkable the formation of pyridinic N-oxide species, which role in the properties of N-containing graphene derivatives has been barely reported. The presence of this fraction is found to confer an enhanced thermal stability to the material.

A BRIEF REVIEW ON GRAPHENE-NANOPARTICLE COMPOSITES

COSMOS ◽  
2010 ◽  
Vol 06 (02) ◽  
pp. 159-166 ◽  
Author(s):  
XIAO HUANG ◽  
FREDDY BOEY ◽  
HUA ZHANG
Keyword(s):  
Graphene Oxide ◽  
Surface Defects ◽  
Single Layer ◽  
Mechanical And Thermal Properties ◽  
Photovoltaic Devices ◽  
Reduced Graphene ◽  
Wide Range ◽  
Graphene Derivatives ◽  
Enhanced Properties ◽  
Nanoparticle Composites

Graphene, a single layer of hexagonal packed carbon atoms, has attracted increasing attention in recent years. Because of its exceptional electronic, optical, mechanical, and thermal properties, graphene has shown great promises in a wide range of applications. Graphene derivatives, e.g. graphene oxide (GO) and reduced graphene oxide (rGO) sheets, possess surface defects and oxygen functional groups, which make them ideal templates for synthesis of metal and semiconductor nanoparticles (NPs). Enhanced properties are expected in these graphene–NP composites, which arise from the synergic effect of the GO/rGO sheets and the anchored NPs. In this review, after a brief introduction on the properties and synthesis of graphene, we will discuss the fabrication methods of graphene–metal NP and graphene–semiconductor NP composites, as well as their related applications in catalysis, photovoltaic devices, supercapacitors, and so on.

Exploring supercapacitance of solvothermally synthesized N-rGO sheet: Role of N-doping and the insight mechanism

2021 ◽  
Author(s):  
Ankit Yadav ◽  
Rajeev Kumar ◽  
Balaram Sahoo
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
N Content ◽  
Nitrogen Doped ◽  
Reduced Graphene ◽  
N Doping

We demonstrate the method of achieving excellent supercapacitance in nitrogen-doped reduced graphene oxide (N-rGO) sheets by controlling the amount of N-content through the use of the different ratios of GO...

scholarly journals Investigation of Graphene Derivatives on Electrical Properties of Alkali Activated Slag Composites

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4374
Author(s):  
Wu-Jian Long ◽  
Xuanhan Zhang ◽  
Biqin Dong ◽  
Yuan Fang ◽  
Tao-Hua Ye ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrical Properties ◽  
Mechanical Performance ◽  
Structural Defects ◽  
Alkali Activated Slag ◽  
Mechanical And Electrical Properties ◽  
Reduced Graphene ◽  
Graphene Derivatives ◽  
Activated Slag ◽  
Alkali Activated

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.

The role of reduced graphene oxide as a “ 2D flexible crosslinking point” in composite hydrogels

2021 ◽  
Author(s):  
Shuang Xia ◽  
Shi Feng ◽  
Zejiang Deng ◽  
Qiuyu Liang ◽  
Xu Xiang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Composite Hydrogels ◽  
Reduced Graphene

Optimizing phthalocyanine based dye-sensitized solar cells: The role of reduced graphene oxide

2018 ◽  
Vol 246 ◽  
pp. 236-245 ◽  
Author(s):  
Francis Chindeka ◽  
Philani Mashazi ◽  
Jonathan Britton ◽  
Gertrude Fomo ◽  
David O. Oluwole ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
Reduced Graphene Oxide ◽  
Dye Sensitized Solar Cells ◽  
Dye Sensitized ◽  
Reduced Graphene ◽  
Sensitized Solar Cells

Synthesis and investigation of thermal properties of PMMA-maleimide-functionalized reduced graphene oxide nanocomposites

2018 ◽  
Vol 33 (1) ◽  
pp. 85-96
Author(s):  
Thangamani Rajkumar ◽  
Nagamuthu Muthupandiyan ◽  
Chinnaswamy Thangavel Vijayakumar
Keyword(s):  
Thermal Stability ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Interaction ◽  
Weight Percent ◽  
Bulk Polymerization ◽  
Pmma Matrix ◽  
Uniform Dispersion ◽  
Reduced Graphene ◽  
Thermal Stability Of

Reduced graphene oxide (RGEO) and N-[4-(chlorocarbonyl)phenyl]maleimide-functionalized reduced graphene oxide (MFRGEO) were used as nanofillers for polymethyl methacrylate (PMMA) matrix nanocomposites to enhance thermal stability. Methyl methacrylate containing nanofiller of four different weight percent (0.2, 0.4, 0.6, and 0.8) was polymerized using ultrasonic radiation-assisted bulk polymerization. The Fourier-transform infrared spectra showed the absence of chemical interaction between the filler and the matrix phase. Morphology of nanocomposites studied using scanning electron microscope confirmed the assistance aided by ultrasonication in the uniform dispersion of nanofiller in the PMMA matrix. Thermogravimetric (TG) study revealed the presence of MFRGEO enhanced the thermal stability of PMMA by shifting the entire degradation to higher temperature. The thermal stability of PMMA nanocomposite was improved by as much as 40°C at just 0.8 wt% loading of MFRGEO. Differential TG study also supported the role of maleimide functionalization on RGEO in the enhancement of thermal stability of PMMA by means of retarding the degradation rate of unsaturated chain ends in the PMMA matrix. Unlike MFRGEO, RGEO failed to enhance the thermal stability of PMMA.

scholarly journals Beneficial Role of Reduced Graphene Oxide for Electron Extraction in Highly Efficient Perovskite Solar Cells

ChemSusChem ◽  
2016 ◽  
Vol 9 (21) ◽  
pp. 3040-3044 ◽  
Author(s):  
Kyung Taek Cho ◽  
Giulia Grancini ◽  
Yonghui Lee ◽  
Dimitrios Konios ◽  
Sanghyun Paek ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
Reduced Graphene Oxide ◽  
Perovskite Solar Cells ◽  
Beneficial Role ◽  
Highly Efficient ◽  
Reduced Graphene ◽  
Electron Extraction
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