Structural evaluation of reduced graphene oxide in graphene oxide during ion irradiation: X-ray absorption spectroscopy and in-situ sheet resistance studies

2018 ◽  
Vol 112 (11) ◽  
pp. 111907 ◽  
Author(s):  
K. Saravanan ◽  
G. Jayalakshmi ◽  
K. Suresh ◽  
B. Sundaravel ◽  
B. K. Panigrahi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Sheet Resistance ◽  
Absorption Spectroscopy ◽  
Ion Irradiation ◽  
X Ray ◽  
Structural Evaluation ◽  
Reduced Graphene ◽  
X Ray Absorption

Facile one pot microbe-mediated in situ synthesis and antibacterial activity of reduced graphene oxide-silver nanocomposite

2021 ◽  
Author(s):  
Ashwini Patil
Keyword(s):  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Zeta Potential ◽  
Reduced Graphene Oxide ◽  
In Vitro Dissolution ◽  
Size Analysis ◽  
X Ray ◽  
Reduced Graphene

Abstract The present research deals with the development of a novel bioinspired in situ fabrication of reduced graphene oxide (rGO)-silver nanoparticle (AgNPs) nanocomposite (rGO@AgNCs) using microbes namely Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA). The fabricated rGO@AgNCs were characterized using Ultraviolet-visible (UV) spectroscopy, Fourier-transform infrared spectroscopy (FTIR), particle size analysis, polydispersity index (PDI), zeta potential analysis, energy dispersive X-ray analysis (EDAX), Raman spectroscopy, powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HR-TEM) analysis, etc. Furthermore, the rGO@AgNCs-PA and rGO@AgNCs-SA interaction with serum protein, pH stability study, and in vitro dissolution of AgNPs were also performed. The research findings of the proposed study demonstrated the simultaneous reduction of graphene oxide (GO) and AgNPs and the formation of rGO@AgNCs in the presence of microbes. The in vitro dissolution studies of rGO@AgNCs composites showed better AgNPs dissolution with controlled release and offered remarkable matrix integrity throughout the dissolution period. The size and stability of rGO@AgNCs-PA and rGO@AgNCs-SA had no significant changes at physiological pH 7.4. A minimal decrease in the zeta potential of rGO@AgNCs was observed, which may be due to the weak interaction of nanocomposites and albumin. The antibacterial application of the synthesized nanocomposite was evaluated against a pathogenic mastitis-forming bacterium. The obtained results suggested an admirable antibacterial activity of synthesized nanocomposites against the tested microbes. This knowledge will assist the scientific fraternity in designing novel antibacterial agents with enhanced antibacterial activity against various veterinary pathogens in near future.

scholarly journals Antibacterial Performance of a Mussel-Inspired Polydopamine-Treated Ag/Graphene Nanocomposite Material

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3360
Author(s):  
Jianming Liao ◽  
Shuaiming He ◽  
Shasha Guo ◽  
Pengcheng Luan ◽  
Lihuan Mo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Antibacterial Properties ◽  
Great Promise ◽  
X Ray ◽  
Antibacterial Performance ◽  
Reduced Graphene ◽  
Wide Range ◽  
Graphene Nanocomposite

Graphene-based nanocomposites have attracted tremendous attention in recent years. In this study, a facile yet effective approach was developed to synthesize reduced graphene oxide and an Ag–graphene nanocomposite. The basic strategy involved in the preparation of reduced graphene oxide includes reducing graphene oxide with dopamine, followed by in situ syntheses of the Ag-PDA-reducing graphene oxide (RGO) nanocomposite through adding AgNO3 solution and a small amount of dopamine. The nanocomposite was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), FTIR spectra, Raman spectra, ultraviolet-visible (UV-vis), and X-ray photoelectron spectroscopy (XPS), results indicated that a uniform PDA film is formed on the surface of the GO and GO is successfully reduced. Besides, the in situ synthesized Ag nanoparticles (AgNPs) were evenly distributed on the RGO surface. To investigate antibacterial properties Ag-PDA-RGO, different dosages were selected for evaluating the antibacterial activity against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. The Ag-PDA-RGO nanocomposites displayed excellent antibacterial property. The antibacterial ratio reached 99.9% against S. aureus and 90.9% against E. coli when the dosage of 100 mg/L Ag-PDA-RGO nanocomposites was 100 μL. The novel Ag-PDA-RGO nanocomposite prepared by a facile yet effective, environmentally friendly, and low-cost method holds great promise in a wide range of modern biomedical applications.

Electrochemical and in situ X-ray spectroscopic studies of MnO2/reduced graphene oxide nanocomposites as a supercapacitor

2016 ◽  
Vol 18 (28) ◽  
pp. 18705-18718 ◽  
Author(s):  
Han-Wei Chang ◽  
Ying-Rui Lu ◽  
Jeng-Lung Chen ◽  
Chi-Liang Chen ◽  
Jyh-Fu Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Spectroscopic Studies ◽  
X Ray ◽  
Reduced Graphene ◽  
Charge Discharge ◽  
Carbon Based

An in situ XAS investigation reveals charge–discharge mechanisms of MnO2/carbon-based materials.

scholarly journals Co2TiO4/Reduced Graphene Oxide Nanohybrids for Electrochemical Sensing Applications

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1611
Author(s):  
Constanza J. Venegas ◽  
Fabiana A. Gutierrez ◽  
Marcos Eguílaz ◽  
José F. Marco ◽  
Nik Reeves-McLaren ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Hybrid Materials ◽  
X Ray ◽  
Reduced Graphene ◽  
Scanning Electron

For the first time, the synthesis, characterization, and analytical application for hydrogen peroxide quantification of the hybrid materials of Co2TiO4 (CTO) and reduced graphene oxide (RGO) is reported, using in situ (CTO/RGO) and ex situ (CTO+RGO) preparations. This synthesis for obtaining nanostructured CTO is based on a one-step hydrothermal synthesis, with new precursors and low temperatures. The morphology, structure, and composition of the synthesized materials were examined using scanning electron microscopy, X-ray diffraction (XRD), neutron powder diffraction (NPD), and X-ray photoelectron spectroscopy (XPS). Rietveld refinements using neutron diffraction data were conducted to determine the cation distributions in CTO. Hybrid materials were also characterized by Brunauer–Emmett–Teller adsorption isotherms, Scanning Electron microscopy, and scanning electrochemical microscopy. From an analytical point of view, we evaluated the electrochemical reduction of hydrogen peroxide on glassy carbon electrodes modified with hybrid materials. The analytical detection of hydrogen peroxide using CTO/RGO showed 11 and 5 times greater sensitivity in the detection of hydrogen peroxide compared with that of pristine CTO and RGO, respectively, and a two-fold increase compared with that of the RGO+CTO modified electrode. These results demonstrate that there is a synergistic effect between CTO and RGO that is more significant when the hybrid is synthetized through in situ methodology.

scholarly journals Spectroscopic Analyses of Changes in Photocatalytic and Catalytic Activities of Mn- and Ni-Ion Doped and Base-Treated Reduced Graphene Oxide

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 990
Author(s):  
Hangil Lee ◽  
Hyun Sung Kim
Keyword(s):  
Electronic Structure ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Metal Ion ◽  
Catalytic Properties ◽  
X Ray ◽  
Catalytic Activities ◽  
Reduced Graphene ◽  
Novel Catalyst ◽  
X Ray Absorption

While reduced graphene oxide (rGO) is used widely as a catalyst, its catalytic activity can be improved significantly by modifying it with a metal. In this study, we compared the photocatalytic and catalytic properties of base-treated rGO particles and transition-metal-ion-doped rGO based on the oxidation reaction of thiophenol and the photocatalytic degradation of 4-chlorophenol. Since the two catalytic activities are related to the changes in the electronic structure of rGO, X-ray photoemission spectroscopy, X-ray absorption spectroscopy, and Raman spectroscopy were performed. When rGO was doped with Mn2+ ions, its catalytic properties improved with respect to both reactions. The changes in the electronic structure of rGO are attributed to the formation of defect structures on the rGO surface via a reaction between the doped Mn2+ ions and oxygen of the rGO surface. Thus, the results show that the doping of rGO with Mn ions in the +2-charge state (stable oxide form: MnO) enhances its catalytic and photocatalytic activities. Hence, this study provides new insights into the use of defect-controlled rGO as a novel catalyst.

Sign in / Sign up

Export Citation Format

Share Document