Effect of Functionalization of Reduced Graphene Oxide Coatings with Nitrogen and Sulfur Groups on Their Anti-Corrosion Properties

Electrophoretic production of anticorrosion carbonaceous coatings on copper could be successfully performed by anodic oxidation of negatively charged graphene platelets suspended in an aqueous solution. The various platelets were synthesized by Hummer’s method followed by a hydrothermal reduction in the presence of NH4SCN which was expected to substitute some parts of graphene structure with nitrogen and sulfur groups. X-ray photoelectron spectroscopy analysis confirmed that the graphene precursors, as well as the coatings, contained typical nitrogen groups, such as pyridinic and pyrrolic, and sulfur groups, such as thiol, thiophene, or C-SO2. However, due to oxidation during deposition, the qualitative and quantitative composition of the graphene coatings changed relative to the composition of the precursors. In particular, the concentration of nitrogen and sulfur dropped and some thiophene groups were oxidized to C-SO2. Studies showed the functionalized coatings had a uniform, defect-free, hydrophobic, more adhesive surface than nonmodified films. The corrosion measurements demonstrated that these coatings had better protective properties than the ones without these heteroatoms. This behavior can be assigned to the catalytic activity of nitrogen towards oxidation of C-SO2 groups to C-SO3H with oxygen.

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Reduced Graphene Oxide–Epoxy Grafted Poly(Styrene-Co-Acrylate) Composites for Corrosion Protection of Mild Steel

Coatings ◽

10.3390/coatings9100666 ◽

2019 ◽

Vol 9 (10) ◽

pp. 666

Author(s):

Xinchuan Fan ◽

Yue Hu ◽

Yijun Zhang ◽

Jiachen Lu ◽

Xiaofeng Chen ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

X Ray Diffraction ◽

Corrosion Properties ◽

X Ray ◽

Transmission Electron ◽

Reduced Graphene ◽

Scanning Electron

Reduced graphene oxide–epoxy grafted poly(styrene-co-acrylate) composites (GESA) were prepared by anchoring different amount of epoxy modified poly(styrene-co-acrylate) (EPSA) onto reduced graphene oxide (rGO) sheets through π–π electrostatic attraction. The GESA composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of rGO/EPSA composites were evaluated by electro-chemical impedance spectroscopy (EIS) in hydroxyl-polyacrylate coating, and the results revealed that the corrosion rate was decreased from 3.509 × 10−1 to 1.394 × 10−6 mm/a.

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VALIDATION OF THE PCR-TEST SYSTEMS FOR ESTIMATION OF QUALITATIVE AND QUANTITATIVE COMPOSITION OF COMMUNITIES OF CHEMOLOTOTROPHIC MICROORGANISMS OF FIELD SHANUCH (KAMCHATKA)

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2017-12-32-278-284 ◽

2017 ◽

Vol 12 (32) ◽

pp. 278-284

Author(s):

S.V. Rogatykh ◽

Keyword(s):

Quantitative Composition ◽

Qualitative And Quantitative ◽

Test Systems ◽

Pcr Test

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Photocatalytic reduction of graphene oxide with cuprous oxide film under UV-vis irradiation

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2020-0022 ◽

2020 ◽

Vol 59 (1) ◽

pp. 207-214 ◽

Cited By ~ 1

Author(s):

Yao Wang ◽

Jianqing Feng ◽

Lihua Jin ◽

Chengshan Li

Keyword(s):

Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Low Cost ◽

Photocatalytic Reduction ◽

Force Microscopy ◽

Atomic Force ◽

Reduced Graphene ◽

Reduction Efficiency ◽

Metal Organic ◽

Reduction Effect

AbstractWe have grown Cu2O films by different routes including self-oxidation and metal-organic deposition (MOD). The reduction efficiency of Cu2O films on graphene oxide (GO) synthesized by modified Hummer’s method has been studied. Surface morphology and chemical state of as-prepared Cu2O film and GO sheets reduced at different conditions have also been investigated using atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). Results show that self-oxidation Cu2O film is more effective on phtocatalytic reduction of GO than MOD-Cu2O film. Moreover, reduction effect of self-oxidation Cu2O film to GO is comparable to that of environmental-friendly reducing agent of vitamin C. The present results offer a potentially eco-friendly and low-cost approach for the manufacture of reduced graphene oxide (RGO) by photocatalytic reduction.

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Influence of Rust Inhibitor on the Corrosion Resistance of Reinforcement in Cement Paste with Chloride

Coatings ◽

10.3390/coatings11050606 ◽

2021 ◽

Vol 11 (5) ◽

pp. 606

Author(s):

Linchun Zhang ◽

Ailian Zhang ◽

Ke Li ◽

Qian Wang ◽

Junzhe Liu ◽

...

Keyword(s):

Corrosion Resistance ◽

Cement Paste ◽

Photoelectron Spectroscopy ◽

Electrical Resistance ◽

Corrosion Properties ◽

Passivation Film ◽

Steel Bars ◽

Assembly Unit ◽

Chloride Environment ◽

Rust Inhibitor

The electrical resistance and polarization effect of cement paste containing reinforcement were tested to research the anti-corrosion properties of steel bars in cement paste. Moreover, the microstructure and composition of passivation film and rust on the steel bars were studied. The water–cement ratio of the cement paste in this study was 0.3, with 0.5% NaCl, 1% NaNO2, and 1% Benzotriazole, and an assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole by mass of cement was added to the cement to provide a chloride environment. X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were applied to research the composition of the passivation film and the microstructure of the cement paste, respectively. The results indicated that the samples with the assembly unit of 0.5% NaNO2 + 0.5% Benzotriazole showed the highest electrical resistance and polarization electrical resistance, while the specimens with 1.0% Benzotriazole showed the lowest electrical resistance and polarization electrical resistance. Moreover, the passivation film of steel bars weakened with increasing distance from the surface of the steel bars. Therefore, the corrosion of steel bars becomes more serious with increasing distance. Finally, the influence of the rust inhibitor on the corrosion resistance of steel bars in the specimens decreased in the following order: 0.5% NaNO2 + 0.5% Benzotriazole >1.0% NaNO2>1.0% Benzotriazole.

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Boron from net charge acceptor to donor and its effect on hydrogen uptake by novel Mg-B-electrochemically synthesized reduced graphene oxide

Scientific Reports ◽

10.1038/s41598-021-90531-w ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Marla V. V. Satya Aditya ◽

Srikanta Panda ◽

Sankara Sarma V. Tatiparti

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Incubation Time ◽

Photoelectron Spectroscopy ◽

Weight Ratio ◽

Hydrogen Uptake ◽

Binding Energies ◽

Unit Cell ◽

Net Charge ◽

Reduced Graphene

AbstractHydrogen uptake (H-uptake) is studied in ball milled Mg-B-electrochemically synthesized reduced graphene oxide (erGO) nanocomposites at PH2 ≈ 15 bar, ~ 320 °C. B/C (weight ratio): 0, ~ 0.09, ~ 0.36, ~ 0.90 are synthesized maintaining erGO≈10wt %. B occupies octahedral interstices within Mg unit cell—revealed by electron density maps. Persistent charge donations from Mg and B to C appear as Mg-C (~ 283.2 eV), B-C (~ 283.3–283.9 eV) interactions in C-1s core X-ray photoelectron spectroscopy (XPS) at all B/C. At B/C > 0.09, charge reception by B from Mg yields Mg-B interaction. This net charge acceptor role of B renders it electron-rich and does not alter Mg unit cell size significantly. Despite charge donation to both C and B, the Mg charge is < + 2, resulting in long incubation times (> 5 h) at B/C > 0.09. At B/C≈0.09 the minimal Mg-B interaction renders B a charge donor, resulting in Mg-B repulsion and Mg unit cell expansion. Mg-C peak shift to lower binding energies (C-1s XPS), decreases incubation time to ~ 2.25 h and enhances H-uptake kinetics. Various atomic interactions influence the reduction of incubation time in H-uptake and increase its kinetics in the order: (Mg → C; B → C)B/C≈0.09, B: donor > (Mg → C)B/C=0 > (ternary Mg → B → C)B/C>0.09, B: acceptor.

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A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽

10.3390/ma13030594 ◽

2020 ◽

Vol 13 (3) ◽

pp. 594 ◽

Cited By ~ 3

Author(s):

Mara Serrapede ◽

Marco Fontana ◽

Arnaud Gigot ◽

Marco Armandi ◽

Glenda Biasotto ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Electrochemical Impedance ◽

Chemical Reduction ◽

Low Cost ◽

Xps Analysis ◽

3D Scaffold ◽

Energy Storage Devices ◽

Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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Anti-oxidative and antimicrobial activities of Hieracium pilosella L. extracts

Journal of the Serbian Chemical Society ◽

10.2298/jsc0805531s ◽

2008 ◽

Vol 73 (5) ◽

pp. 531-540 ◽

Cited By ~ 16

Author(s):

Ljiljana Stanojevic ◽

Mihajlo Stankovic ◽

Vesna Nikolic ◽

Ljubisa Nikolic

Keyword(s):

Salmonella Enteritidis ◽

Radical Scavenging ◽

Antimicrobial Activities ◽

Diffusion Method ◽

Quantitative Composition ◽

Minimal Inhibitory Concentrations ◽

Qualitative And Quantitative ◽

Scavenging Effect ◽

Hieracium Pilosella ◽

Radical Scavenging Effect

The anti-oxidative and antimicrobial activities of different extracts from Hieracium pilosella L. (Asteraceae) whole plant were investigated. The total dry extracts were determined for all the investigated solvents: methanol, dichloromethane, ethyl acetate and dichloromethane: methanol (9:1). It was found that the highest yield was obtained by extraction with methanol (12.9 g/100 g of dry plant material). Qualitative and quantitative analysis were performed by the HPLC method, using external standards. Chlorogenic acid, apigenin-7-O-glucoside and umbelliferone were detected in the highest quantity in the extracts. The qualitative and quantitative composition of the extracts depends on the solvent used. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging effect of the extracts was determined spectrophotometrically. The highest radical scavenging effect was observed in the methanolic extract, both with and without incubation, EC50 = 0.012 and EC50 = 0.015 mg ml-1, respectively. The antimicrobial activities of the extracts towards the bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Salmonella enteritidis and Klebsiella pneumoniae) and the fungi (Aspergillus niger and Candida albicans) were determined by the disc diffusion method. The minimal inhibitory concentrations were determined for all the investigated extracts against all the mentioned microorganisms.

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Chemistry and Biology of Essential Oils of GenusBoswellia

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2013/140509 ◽

2013 ◽

Vol 2013 ◽

pp. 1-12 ◽

Cited By ~ 10

Author(s):

Hidayat Hussain ◽

Ahmed Al-Harrasi ◽

Ahmed Al-Rawahi ◽

Javid Hussain

Keyword(s):

Essential Oils ◽

Current Knowledge ◽

Biological Activities ◽

Ethanolic Extract ◽

Quantitative Composition ◽

Volatile Constituents ◽

Traditional Medicines ◽

Qualitative And Quantitative ◽

Synthetic Drugs ◽

Explicit Consideration

The properties ofBoswelliaplants have been exploited for millennia in the traditional medicines of Africa, China, and especially in the Indian Ayurveda. In Western countries, the advent of synthetic drugs has obscured the pharmaceutical use ofBoswellia, until it was reported that an ethanolic extract exerts anti-inflammatory and antiarthritic effects. Frankincense was commonly used for medicinal purposes. This paper aims to provide an overview of current knowledge of the volatile constituents of frankincense, with explicit consideration concerning the diverseBoswelliaspecies. Altogether, more than 340 volatiles inBoswelliahave been reported in the literature. In particular, a broad diversity has been found in the qualitative and quantitative composition of the volatiles with respect to different varieties ofBoswellia. A detailed discussion of the various biological activities ofBoswelliafrankincense is also presented.

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