Facile Synthesis of Modified MnO2/Reduced Graphene Oxide Nanocomposites and their Application in Supercapacitors

Herein, KH-550 was used as surface modifier to prepare modified MnO2/reduced graphene oxide (M-MnO2/rGO) composite electrode materials by utilizing electrostatic interaction at low temperature and normal pressure. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy were adopted to characterize the material’s phase, morphology, and valence state of elements. The electrochemical properties of the material were measured using a three-electrode system. The results indicate a decrease in the size of the modified MnO2 particles, and that they were uniformly distributed on the rGO sheets. The M-MnO2/rGO composite attained a specific capacitance of 326[Formula: see text]F[Formula: see text]g[Formula: see text] in a solution of 1[Formula: see text]mol[Formula: see text]L[Formula: see text] Na2SO4 at a current density of 0.5[Formula: see text]A[Formula: see text]g[Formula: see text]. The specific capacitance of the material was 92.4% after 1000 cycles. The electrostatic self-assembly method effectively solved the problem of reducing the cycling stability while improving the specific capacitance of the composite materials, and further improved the possibility of applying MnO2/rGO in the field of supercapacitors.

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Template-free synthesis of Se-nanorods-rGO nanocomposite for application in supercapacitors

Nanotechnology Reviews ◽

10.1515/ntrev-2019-0057 ◽

2019 ◽

Vol 8 (1) ◽

pp. 661-670 ◽

Cited By ~ 1

Author(s):

Zafar Khan Ghouri ◽

Moaaed Motlak ◽

Shagufta Afaq ◽

Nasser A. M. Barakat ◽

Ahmed Abdala

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Specific Capacitance ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

High Specific Capacitance ◽

Nitrogen Adsorption ◽

X Ray ◽

Reduced Graphene ◽

Template Free

AbstractBoth selenium and reduced graphene oxide have low specific capacitance due to their chemical nature. Nevertheless, their specific capacitance could be enhanced by hybridizing Se nanomaterials with reduced graphene oxide via formation of electrochemical double layer at their interfacial area. Therefore, novel Se-nanorods/rGO nanocomposite was successfully synthesized by template free hot reflux route starting with graphene oxide and selenium dichloride. The composite of rGO decorated by Se-nanorods is characterized using X-ray diffractometry (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption– desorption. The unique architecture of the composite exhibits high specific capacitance of 390 F/ g at 5 mV/s scan rate in 1.0 M KOH solution with ~ 90% cyclic stability after 5000 cycles making it very promising electrode material for supercapacitor applications.

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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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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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Nitrogen-Enriched Reduced Graphene Oxide for High Performance Supercapacitor Electrode

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.18496 ◽

2020 ◽

Vol 20 (8) ◽

pp. 4854-4859 ◽

Cited By ~ 2

Author(s):

Lei Chen ◽

Xu Chen ◽

Yaqiong Wen ◽

Bixia Wang ◽

Yangchen Wu ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Specific Capacitance ◽

Reduced Graphene Oxide ◽

Electrode Material ◽

High Performance ◽

Electrode Materials ◽

Electrochemical Impedance ◽

Oxide Electrode ◽

Reduced Graphene

Nitrogen-enriched reduced graphene oxide electrode material can be successfully prepared through a simple hydrothermal method. The morphology and microstructure of ready to use electrode material is measured by field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). Physical characterizations revealed that nitrogen-enriched reduced graphene oxide electrode material possessed high specific surface area of 429.6 m2 · g−1, resulting in high utilization of electrode materials with electrolyte. Electrochemical performance of nitrogen-enriched reduced graphene oxide electrode was also investigated by cyclic voltammetry (CV), galvanostatic charge/discharge measurements and electrochemical impedance spectroscopy (EIS) in aqueous in 6 M KOH with a three-electrode system, which displayed a high specific capacitance about 223.5 F · g−1 at 1 mV · s−1. More importantly, nitrogenenriched reduced graphene oxide electrode exhibited outstanding stability with 100% coulombic efficiency and with no specific capacitance loss under 2 A · g−1 after 10000 cycles. The supercapacitive behaviors indicated that nitrogen-enriched reduced graphene oxide can be a used as a promising electrode for high-performance super-capacitors.

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Zirconia Reduced Graphene Oxide Nano-Hybrid Structure Fabricated by the Hydrothermal Reaction Method

Materials ◽

10.3390/ma13030687 ◽

2020 ◽

Vol 13 (3) ◽

pp. 687 ◽

Cited By ~ 4

Author(s):

Anton Smirnov ◽

Nestor Washington Solís Pinargote ◽

Nikita Peretyagin ◽

Yuri Pristinskiy ◽

Pavel Peretyagin ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Hydrothermal Reaction ◽

Hybrid Structure ◽

X Ray ◽

Transmission Electron ◽

Reduced Graphene ◽

Nanocomposite Powders

In this work, we report an available technique for the effective reduction of graphene oxide (GO) and the fabrication of nanostructured zirconia reduced graphene oxide powder via a hydrothermal method. Characterization of the obtained nano-hybrid structure materials was carried out using a scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). The confirmation that GO was reduced and the uniform distribution of zirconia nanoparticles on graphene oxide sheets during synthesis was obtained due to these techniques. This has presented new opportunities and prospects to use this uncomplicated and inexpensive technique for the development of zirconia/graphene nanocomposite powders.

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Reduced graphene oxide supported C3N4 nanoflakes and quantum dots as metal-free catalysts for visible light assisted CO2 reduction

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.10.44 ◽

2019 ◽

Vol 10 ◽

pp. 448-458 ◽

Cited By ~ 5

Author(s):

Md Rakibuddin ◽

Haekyoung Kim

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Visible Light ◽

Reduced Graphene Oxide ◽

Hybrid Materials ◽

Photoelectron Spectroscopy ◽

X Ray ◽

Metal Free ◽

Reduced Graphene ◽

Vis Spectroscopy

The visible light photocatalytic reduction of CO2 to fuel is crucial for the sustainable development of energy resources. In our present work, we report the synthesis of novel reduced graphene oxide (rGO)-supported C3N4 nanoflake (NF) and quantum dot (QD) hybrid materials (GCN) for visible light induced reduction of CO2. The C3N4 NFs and QDs are prepared by acid treatment of C3N4 nanosheets followed by ultrasonication and hydrothermal heating at 130–190 °C for 5−20 h. It is observed that hydrothermal exposure of acid-treated graphitic carbon nitride (g-C3N4) nanosheets at low temperature generated larger NFs, whereas QDs are formed at higher temperatures. The formation of GCN hybrid materials was confirmed by powder X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy (TEM), and UV–vis spectroscopy. High-resolution TEM images clearly show that C3N4 QDs (average diameter of 2–3 nm) and NFs (≈20–45 nm) are distributed on the rGO surface within the GCN hybrid material. Among the as-prepared GCN hybrid materials, GCN-5 QDs exhibit excellent CO2 reductive activity for the generation of formaldehyde, HCHO (10.3 mmol h−1 g−1). Therefore, utilization of metal-free carbon-based GCN hybrid materials could be very promising for CO2 photoreduction because of their excellent activity and environmental sustainability.

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Silver Nanoparticles Embedded on Reduced Graphene Oxide@Copper Oxide Nanocomposite for High Performance Supercapacitor Applications

Materials ◽

10.3390/ma14175032 ◽

2021 ◽

Vol 14 (17) ◽

pp. 5032

Author(s):

Akhalakur Rahman Ansari ◽

Sajid Ali Ansari ◽

Nazish Parveen ◽

Mohammad Omaish Ansari ◽

Zurina Osman

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Electrochemical Performance ◽

Specific Capacitance ◽

Reduced Graphene Oxide ◽

High Specific Capacitance ◽

Hydrothermal Route ◽

X Ray ◽

Reduced Graphene ◽

Cuo Nanosheets

In this work, silver (Ag) decorated reduced graphene oxide (rGO) coated with ultrafine CuO nanosheets (Ag-rGO@CuO) was prepared by the combination of a microwave-assisted hydrothermal route and a chemical methodology. The prepared Ag-rGO@CuO was characterized for its morphological features by field emission scanning electron microscopy and transmission electron microscopy while the structural characterization was performed by X-ray diffraction and Raman spectroscopy. Energy-dispersive X-ray analysis was undertaken to confirm the elemental composition. The electrochemical performance of prepared samples was studied by cyclic voltammetry and galvanostatic charge-discharge in a 2M KOH electrolyte solution. The CuO nanosheets provided excellent electrical conductivity and the rGO sheets provided a large surface area with good mesoporosity that increases electron and ion mobility during the redox process. Furthermore, the highly conductive Ag nanoparticles upon the rGO@CuO surface further enhanced electrochemical performance by providing extra channels for charge conduction. The ternary Ag-rGO@CuO nanocomposite shows a very high specific capacitance of 612.5 to 210 Fg−1 compared against rGO@CuO which has a specific capacitance of 375 to 87.5 Fg−1 and the CuO nanosheets with a specific capacitance of 113.75 to 87.5 Fg−1 at current densities 0.5 and 7 Ag−1, respectively.

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A study on the influence of reduced graphene oxide on the mechanical, dynamic mechanical and tribological properties of silicone rubber nanocomposites

Journal of Composite Materials ◽

10.1177/0021998320981608 ◽

2020 ◽

pp. 002199832098160

Author(s):

PS Sarath ◽

Grace Moni ◽

Jinu Jacob George ◽

Józef T Haponiuk ◽

Sabu Thomas ◽

...

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Wear Rate ◽

Reduced Graphene Oxide ◽

Silicone Rubber ◽

Photoelectron Spectroscopy ◽

Applied Load ◽

Adhesive Film ◽

X Ray ◽

Reduced Graphene

Graphene oxide (GO) was synthesized by modified Hummer’s method and it reduced with hydrazine. Synthesized reduced graphene oxide (rGO) was characterized by FT-IR spectroscopy, X-ray diffraction spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. An elastomeric nanocomposite was prepared by incorporating rGO in silicone rubber using two roll mill mixing method.Tribological study was conducted at a wear surface of hardened ground steel against different applied load, sliding speed and temperature using a pin on disk setup. Addition of rGO results in an improvement of mechanical, tribological and thermal properties of silicone rubber. The coefficient friction (COF) and specific wear rate of the nanocomposite decreased with rGO concentration, applied load, and temperature. Morphological analysis of SRrGO nanocomposites was deeply investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Worn surface analysis confirms that rGO forms a lubricant film on the counter surface but it fails to form a strong adhesive film on the metal surface. The depth wear rate decreased by the incorporation of rGO in the Silicone rubber (SR) matrix.

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Synthesis of holey reduced graphene oxide covered in the FeCo@SiO2 and their enhanced electromagnetic absorption properties

Journal of Composite Materials ◽

10.1177/0021998318817358 ◽

2018 ◽

Vol 53 (14) ◽

pp. 1973-1983 ◽

Cited By ~ 3

Author(s):

Suping Li ◽

Ying Huang ◽

Na Zhang ◽

Meng Zong

Keyword(s):

Electron Microscopy ◽

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Reflection Loss ◽

Photoelectron Spectroscopy ◽

Absorption Properties ◽

Absorption Bandwidth ◽

X Ray ◽

Oxide Composite ◽

Reduced Graphene

The FeCo@SiO2/holey reduced graphene oxide composite was successfully prepared by combining liquid-phase reduction reaction in argon atmosphere with high-temperature calcination. The FeCo@SiO2/holey reduced graphene oxide composite was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, vibrating sample magnetometer, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and scanning electron microscopy analysis and exhibit excellent electromagnetic wave absorption properties. The maximum reflection loss of FeCo@SiO2/holey reduced graphene oxide composite reaches –46.28 dB at 16.16 GHz with the thickness of 1.5 mm and the absorption bandwidth with the reflection loss below –10 dB was up to 3.92 GHz (from 14.08 GHz to 18 GHz) with the thickness of 1.5 mm. The absorption bandwidth with RL below –10 dB is up to 12.64 GHz. It is believed that the FeCo@SiO2/holey reduced graphene oxide composite can serve as an excellent microwave absorber.

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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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