In-depth understanding of the photoreduction of graphene oxide to reduced-graphene oxide on TiO2 surface: statistical analysis of X-ray photoelectron and Raman spectroscopy data

In this paper, various graphite oxide (GO) and reduced graphene oxide (rGO) preparation methods are analyzed. The obtained materials differed in their properties, including (among others) their oxygen contents. The chemical and structural properties of graphite, graphite oxides, and reduced graphene oxides were previously investigated using Raman spectroscopy (RS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). In this paper, hierarchical clustering analysis (HCA) and analysis of variance (ANOVA) were used to trace the directions of changes of the selected parameters relative to a preparation method of such oxides. We showed that the oxidation methods affected the physicochemical properties of the final products. The aim of the research was the statistical analysis of the selected properties in order to use this information to design graphene oxide materials with properties relevant for specific applications (i.e., in gas sensors).

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X-ray Absorption Spectroscopic Study on Interfacial Electronic Properties of FeOOH/Reduced Graphene Oxide for Asymmetric Supercapacitors

ACS Sustainable Chemistry & Engineering ◽

10.1021/acssuschemeng.6b02970 ◽

2017 ◽

Vol 5 (4) ◽

pp. 3186-3194 ◽

Cited By ~ 10

Author(s):

Han-Wei Chang ◽

Chung-Li Dong ◽

Ying-Rui Lu ◽

Yu-Cheng Huang ◽

Jeng-Lung Chen ◽

...

Keyword(s):

Graphene Oxide ◽

Spectroscopic Study ◽

Electronic Properties ◽

Reduced Graphene Oxide ◽

Asymmetric Supercapacitors ◽

X Ray ◽

Reduced Graphene ◽

X Ray Absorption

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

Nanotechnology ◽

10.1088/1361-6528/ac4521 ◽

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.

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Reduced Graphene Oxide Supported Molybdenum Oxide Hybrid Nanocomposites: High Performance Electrode Material for Supercapacitor and Photocatalytic Applications

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17779 ◽

2020 ◽

Vol 20 (7) ◽

pp. 4035-4046

Author(s):

Rengasamy Dhanabal ◽

Dhanasekaran Naveena ◽

Sivan Velmathi ◽

Arumugam Chandra Bose

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Diffuse Reflectance Spectroscopy ◽

Hybrid Nanocomposites ◽

X Ray ◽

Supercapacitor Application ◽

Quenching Effect ◽

Reduced Graphene

Using a simple solution based synthesis route, hexagonal MoO3 (h-MoO3) nanorods on reduced graphene oxide (RGO) sheets were prepared. The structure and morphology of resulting RGO-MoO3 nanocomposite were characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The optical property was studied using UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS) and photoluminescence spectroscopy (PL). The RGO-MoO3 nanocomposites were used as an electrode for supercapacitor application and photocatalyst for photodegradation of methylene blue (MB) and rhodamine B (RhB) under visible light irradiation. We demonstrated that the RGO-MoO3 electrode is capable of delivering high specific capacitance of 134 F/g at current density of 1 A/g with outstanding cyclic stability for 2000 cycles. The RGOMoO3 photocatalyst degrades 95% of MB dye within 90 min, and a considerable recyclability up to 4 cycles was observed. The quenching effect of scavengers test confirms holes are main reactive species in the photocatalytic degradation of MB. Further, the charge transfer process between RGO and MoO3 was schematically demonstrated.

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Effects of Different TiO2 Particle Sizes on the Microstructure and Optical Limiting Properties of TiO2/Reduced Graphene Oxide Nanocomposites

Nanomaterials ◽

10.3390/nano9050730 ◽

2019 ◽

Vol 9 (5) ◽

pp. 730 ◽

Cited By ~ 4

Author(s):

Yuyu Ren ◽

Lili Zhao ◽

Yang Zou ◽

Lixin Song ◽

Ningning Dong ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Optical Limiting ◽

Tio2 Particle ◽

Tetrabutyl Titanate ◽

Particle Sizes ◽

X Ray ◽

Reduced Graphene ◽

Source Materials

TiO2/reduced graphene oxide (rGO) nanocomposites with two different TiO2 particle sizes were synthesized by a facile hydrothermal method using two different source materials of Ti: tetrabutyl titanate (TBT) and commercial TiO2 powder (P25). For respective series with the same source materials, we investigated additions that optimized the nonlinear optical properties (NLO) and optical limiting (OL) performances, and we explored the relationships between structural diversity and performance. Several characterization techniques, including X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and diffuse reflectance ultraviolet-visible spectroscopy (UV-Vis) were conducted to confirm the microstructures and chemical states of as-prepared materials. This indicated the existence of the Ti–O–C bond between rGO sheets and TiO2 particles and the reduction from precursor graphene oxide (GO) to rGO. The results of UV-Vis spectra revealed that the TiO2/rGO nanocomposites showed smaller band gaps than bare TiO2. A nanosecond open-aperture Z-scan technique at 1064 nm was applied to investigate NLO and OL properties. TiO2/rGO nanocomposites exhibited enhanced NLO and OL performances, arising from synergistic effects, compared to individual components. The TBT series samples performed better than the P25 series, presumably relevant to dimensional effects.

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Reduced Graphene Oxide-Wrapped Super Dense Fe3O4 Nanoparticles with Enhanced Electromagnetic Wave Absorption Properties

Nanomaterials ◽

10.3390/nano9060845 ◽

2019 ◽

Vol 9 (6) ◽

pp. 845

Author(s):

Qi Yu ◽

Yiyi Wang ◽

Ping Chen ◽

Weicheng Nie ◽

Hanlin Chen ◽

...

Keyword(s):

Graphene Oxide ◽

Electromagnetic Wave ◽

Electron Microscope ◽

Reduced Graphene Oxide ◽

Fe3o4 Nanoparticles ◽

Absorption Properties ◽

Electromagnetic Wave Absorption ◽

X Ray ◽

Wave Absorption ◽

Reduced Graphene

The efficient preparation of electromagnetic wave absorbing materials with low density and excellent electromagnetic wave absorption remains a considerable challenge. In this study, reduced graphene oxide (RGO) wrapped Fe3O4 nanoparticles (NPs) were synthesized based on one-step reaction by the reduction of graphene oxide (GO), and the generation of super-fine Fe3O4 NPs was achieved. The phase structure, chemical composition, micromorphology, and magnetism were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM), respectively. The electromagnetic characteristics were evaluated on a vector network analyzer by the coaxial line method. The results showed that super-fine Fe3O4 NPs with an average size of 6.18 nm are densely distributed on the surface of graphenes. The RGO/Fe3O4 nanocomposites exhibited excellent microwave absorption properties with a minimum reflection loss (RL) of up to −55.71 dB at 6.78 GHz at 3.5 mm thickness and the highest effective absorption bandwidth with RL values exceeding −10 dB is 4.76 GHz between 13.24 and 18 GHz at 1.7 mm thickness. This work provides a concise method for the development of RGO supported super dense Fe3O4 nanocomposites for high performance electromagnetic absorption applications.

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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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Study on Magnetic Properties of Na-Doped rGO Prepared from Coconut Shells

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.855.160 ◽

2020 ◽

Vol 855 ◽

pp. 160-165

Author(s):

Deril Ristiani ◽

Niken Sylvia Puspitasari ◽

Retno Asih ◽

Fahmi Astuti ◽

Malik Anjelh Baqiya ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Mixing Process ◽

X Ray Diffraction ◽

X Ray ◽

Reduced Graphene ◽

Naoh Solution ◽

Na Ions ◽

Diffraction Peaks ◽

Coconut Shells

Na-doped reduced graphene oxide (Na-rGO) was prepared by wet mixing process of the reduced graphene oxide (rGO) in NaOH solution. The results showed that the rGO doped with Na ions can increase its magnetization approximately 2 times greater than that in rGO without doping. Saturation magnetization (Ms) for rGO and Na-rGO samples are 0.017 emu/g and 0.037 emu/g, respectively. The increasing value of magnetization is suggested to be due to defect presented in the Na-rGO samples. Both samples, rGO and Na-rGO, have the similar XRD (X-ray Diffraction) spectra that is marked by two characteristic diffraction peaks of rGO, which are associated with [002] and [10] planes, followed by the increasing inter-planar distance in Na-rGO samples which might be due to Na ions intercalation into rGO sheets, confirmed by the energy-dispersive X-ray (EDX) result revealing the presence of Na atoms in rGO.

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Elucidating the Chemistry behind the Reduction of Graphene Oxide Using a Green Approach with Polydopamine

Nanomaterials ◽

10.3390/nano9060902 ◽

2019 ◽

Vol 9 (6) ◽

pp. 902 ◽

Cited By ~ 9

Author(s):

Cláudia Silva ◽

Frank Simon ◽

Peter Friedel ◽

Petra Pötschke ◽

Cordelia Zimmerer

Keyword(s):

Raman Spectroscopy ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

New Approach ◽

Oh Groups ◽

Chemical Treatments ◽

Green Approach ◽

Reduced Graphene ◽

Thermal And Electrical Properties

A new approach using X-ray photoelectron spectroscopy (XPS) was employed to give insight into the reduction of graphene oxide (GO) using a green approach with polydopamine (PDA). In this approach, the number of carbon atoms bonded to OH and to nitrogen in PDA is considered and compared to the total intensity of the signal resulting from OH groups in polydopamine-reduced graphene oxide (PDA-GO) to show the reduction. For this purpose, GO and PDA-GO with different times of reduction were prepared and characterized by Raman Spectroscopy and XPS. The PDA layer was removed to prepare reduced graphene oxide (RGO) and the effect of all chemical treatments on the thermal and electrical properties of the materials was studied. The results show that the complete reduction of the OH groups in GO occurred after 180 min of reaction. It was also concluded that Raman spectroscopy is not well suited to determine if the reduction and restoration of the sp2 structure occurred. Moreover, a significant change in the thermal stability was not observed with the chemical treatments. Finally, the electrical powder conductivity decreased after reduction with PDA, increasing again after its removal.

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