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1

The Oxygen Reduction Activity of Nitrogen-doped Graphene

Jian-feng Liu, Ge Sun, Ting Wang, Kai Ning, Bin-xia Yuan, Wei-guo Pan

Polish Journal of Chemical Technology

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2022

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Vol. 24, nr 3

29--34

EN

Graphite nitrogen, pyridine nitrogen and pyrrole nitrogen are the main nitrogen types in nitrogen-doped graphene materials. In order to investigate the mechanism of the oxygen reduction activity of nitrogen-doped graphene, several models of nitrogen-doped graphene with different nitrogen contents and different nitrogen types are developed. The nitrogen content is varied from 1.3 at% to 7.8 at%, and the adsorption energy is calculated according to the established models, then the band gaps are analyzed through the optimization results, so as to compare the mag-nitude of the conductivity. Finally, the oxygen reduction activity of graphite nitrogen-doped graphene (GNG) is found to be better than pyridine nitrogen-doped graphene (PDNG) and pyrrole nitrogen-doped graphene (PLNG) when the nitrogen content is lower than 2.6 at%, and the oxygen reduction activity of PDNG is the best when the nitrogen content was higher than 2.6 at%.

2

Preparation and properties of nanocrystalline Ni/graphene composite coatings deposited by electrochemical method

Cieślak G., Trzaska M.

Polish Journal of Chemical Technology

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2018

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Vol. 20, nr 1

29--34

EN

The paper presents results of studies of composite nickel/graphene coatings produced by electrodeposition method on a steel substrate. The method of producing composite coatings with nanocrystalline nickel matrix and dispersion phase in the form of graphene is presented. For comparative purposes, the study also includes nano-crystalline Ni coatings produced by electrochemical reduction without built-in graphene flakes. Graphene was characterized by Raman spectroscopy, transmission and scanning electron microscopes. Results of studies on the structure and morphology of Ni and Ni/graphene layers produced in a bath containing different amounts of graphene are presented. Material of the coatings was characterized by SEM, light microscopy, X-ray diffraction. The microhardness of the coatings was examined by Knoop measurements. The adhesion of the coatings with the substrate was tested using a scratchtester. The influence of graphene on the structure and properties of composite coatings deposited from a bath with different graphene contents was determined.

3

Alternative transparent conducting electrode materials for flexible optoelectronic devices

Sharma S., Shriwastava S., Kumar S., Bhatt K., Tripathi C. C.

Opto-Electronics Review

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2018

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Vol. 26, No. 3

223--235

EN

Transparent Conductive Electrode (TCE) is an essential part of the optoelectronic and display devices such as Liquid Crystal Displays (LCDs), Solar Cells, Light Emitting Diodes (LEDs), Organic Light Emitting Diodes (OLEDs) and touch screens. Indium Tin Oxide (ITO) is a commonly used TCE in these devices because of its high transparency and low sheet resistance. However, scarcity of indium and brittle nature of ITO limit its use in future flexible electronics. In order to develop flexible optoelectronic devices with improved performance, there is a requirement of replacing the ITO with a better alternate TCE. In this work, several alternative TCEs including transparent conductive oxides, carbon nanotubes, conducting polymers, metal nanowires, graphene and composites of these materials are studied with their properties such as sheet resistance, transparency and flexibility. The advantage and current challenges of these materials are also presented in this work.

4

Influence of environmental media on carbon nanotubes and graphene nanoplatelets towards bacterial toxicity

Baysal A., Saygin H., Ustabasi G. S.

Archives of Environmental Protection

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2018

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Vol. 44, no. 3

85--98

EN

Functional carbon-based nanomaterials have become important due to their unique combinations of chemical and physical properties, and also because of the increasing research efforts in various fi elds. A signifi cant gap in nanotechnology is the disregarding of physicochemical transformation under real conditions for the examination and comparison on the effect of carbon based nanomaterials. In this study, the behavior of some carbon based nanomaterials (multi-walled carbon nanotubes and graphene nanoplatelets) in environmental media (sea water, soil, and airborne fi ne particulate) were evaluated by using the infl uence on nanomaterial physicochemical properties (size, zeta potential, surface chemistry, morphology and sedimentation) and on the toxicity of bacterium (gram positive and gram negative bacteria) to contribute to their environmental hazard and risk assessment on the environment. The bacteria were exposed to the carbon based nanomaterials, and cultivated on nutrient agar plates including each environmental media, and then counted for the colony forming units. The physicochemical properties of the carbon based nanomaterials dispersed in these environmental media were also investigated. Our results indicated that the toxicity depended on the type of environmental media and their concentration, and the physicochemical properties of the carbon based nanomaterials changed when compared to the results obtained in controlled conditions.

5

Fabrication Fe/Fe3O4/Graphene Nanocomposite Electrode Material for Rechargeable Ni/Fe Batteries in Hybrid Electric Vehicles

Kumar H., Shukla A. K.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 14

15--25

EN

Fe/Fe3O4/Graphene composite electrode material was synthesized by a thermal reduction method and then used as anode material along with Nickel cathode in rechargeable Ni/Fe alkaline batteries in hybrid electric vehicles. Reduced graphene /Fe/Fe3O4 composite electrode material was prepared using a facile three step synthesis involving synthesis of iron oxalate and subsequent reduction of exfoliated graphene oxide and iron oxalate by thermal decomposition method. The synthesis approach presents a promising route for a large-scale production of reduced graphene /Fe/Fe3O4 composite as electrode material for Ni/Fe rechargeable batteries. The particle size and structure of the samples were characterized by SEM and XRD.