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

Materials ◽  
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.

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

2019 ◽  
Vol 8 (1) ◽  
pp. 661-670 ◽  
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.

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

NANO ◽  
2020 ◽  
Vol 15 (08) ◽  
pp. 2050099
Author(s):  
Lijun Chen ◽  
Hongfeng Yin ◽  
Yuchao Zhang ◽  
Huidong Xie
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrode Materials ◽  
Normal Pressure ◽  
X Ray ◽  
Assembly Method ◽  
Reduced Graphene

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.

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

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.

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

Coatings ◽  
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.

scholarly journals Dissected carbon nanotubes functionalized by 1-hydroxyanthraquinone for high-performance asymmetric supercapacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (76) ◽  
pp. 48341-48353 ◽  
Author(s):  
Xia Yang ◽  
Yuying Yang ◽  
Quancai Zhang ◽  
Xiaotong Wang ◽  
Yufeng An ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Specific Capacitance ◽  
Reduced Graphene Oxide ◽  
High Performance ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
Covalent Modification ◽  
Asymmetric Supercapacitors ◽  
Reduced Graphene

1-Hydroxyanthraquinone (HAQ) is selected to functionalize the dissected carbon nanotubes (rDCNTs) with reduced graphene oxide layers through non-covalent modification. The composite achieves high specific capacitance and ultrahigh rate capability.

scholarly journals Facile Fabrication of CeO2/Electrochemically Reduced Graphene Oxide Nanocomposites for Vanillin Detection in Commercial Food Products

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1356 ◽  
Author(s):  
Xue Nie ◽  
Rui Zhang ◽  
Zheng Tang ◽  
Haiyan Wang ◽  
Peihong Deng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Linear Sweep Voltammetry ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Electrochemically Reduced Graphene Oxide ◽  
Wide Range ◽  
Facile Fabrication

In this paper, CeO2 nanoparticles were synthesized by the solvothermal method and dispersed uniformly in graphene oxide (GO) aqueous solution by ultrasonication. The homogeneous CeO2-GO dispersion was coated on the surface of a glassy carbon electrode (GCE), and the CeO2/electrochemically reduced graphene oxide modified electrode (CeO2/ERGO/GCE) was obtained by potentiostatic reduction. The results of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) showed that CeO2 nanocrystals were uniformly coated by gossamer like ERGO nanosheets. The electrochemical behavior of vanillin on the CeO2/ERGO/GCE was studied by cyclic voltammetry (CV). It was found that the CeO2/ERGO/GCE has high electrocatalytic activity and good electrochemical performance for vanillin oxidation. Using the second derivative linear sweep voltammetry (SDLSV), the CeO2/ERGO/GCE provides a wide range of 0.04–20 µM and 20 µM–100 µM for vanillin detection, and the detection limit is estimated to be 0.01 µM after 120 s accumulation. This method has been successfully applied to the vanillin detection in some commercial foods.

scholarly journals Incorporation of reduced graphene oxide into faceted flower-like {001} TiO 2 for enhanced photocatalytic activity

2018 ◽  
Vol 5 (8) ◽  
pp. 180613 ◽  
Author(s):  
Haijin Liu ◽  
Peiyao Li ◽  
Haokun Bai ◽  
Cuiwei Du ◽  
Dandan Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Reduced Graphene Oxide ◽  
Theoretical Calculations ◽  
X Ray ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Photocatalytic Activities

Anatase TiO 2 with {001} facets is much more active than that with {101} facets, which has been verified via experiments and theoretical calculations. Graphene has garnered much attention since it was initially synthesized, due to its unique properties. In this study, reduced graphene oxide (RGO)/{001} faceted TiO 2 composites were fabricated via a solvothermal method. The composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectrophotometry, photoluminescence and Raman analysis. The results revealed that the graphene oxide was reduced during the preparation process of the {001} faceted TiO 2 , and combined with the surface of {001} TiO 2 . The photocatalytic activities of the composites were evaluated through the degradation of basic violet, under both white light ( λ > 390 nm) and visible light ( λ = 420 nm) irradiation. The results indicated that the photocatalytic activities of the {001} faceted TiO 2 were significantly improved following the incorporation of RGO, particularly under visible light irradiation. Theoretical calculations showed that the band structure of the {001} faceted TiO 2 was modified via graphene hybridization, where the separation of photoinduced electron–hole pairs was promoted; thus, the photocatalytic activity was enhanced.

Nitrogen-Enriched Reduced Graphene Oxide for High Performance Supercapacitor Electrode

2020 ◽  
Vol 20 (8) ◽  
pp. 4854-4859 ◽  
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.

Co3O4 Nanoparticles-Modified α-MnO2 Nanorods Supported on Reduced Graphene Oxide as Cathode Catalyst for Oxygen Reduction Reaction in Alkaline Media

NANO ◽  
2016 ◽  
Vol 11 (11) ◽  
pp. 1650126 ◽  
Author(s):  
GuanHua Jin ◽  
Suqin Liu ◽  
Yaomin Li ◽  
Yang Guo ◽  
Zhiying Ding
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Catalytic Activity ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduced Graphene Oxide ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
X Ray ◽  
Reduced Graphene

Development of efficient electrocatalysts for the oxygen reduction reaction (ORR) remains a key issue for the commercialization of metal-air batteries. In this study, the novel structured Co3O4 nanoparticles-modified [Formula: see text]-MnO2 nanorods supported on reduced graphene oxide (Co3O4-MnO2/rGO) were synthesized with varying amounts of [Formula: see text]-MnO2 via a facile two-step hydrothermal method. The relationship between the physical properties and the electrochemical results was investigated using X-ray diffraction spectrum, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, cyclic voltammograms, electrochemical impedance spectroscopy and rotating disk electrode. The as-prepared Co3O4–MnO2 nanohybrid exhibits enhanced catalytic activity for ORR under alkaline condition compared with MnO2/rGO and Co3O4/rGO. Furthermore, it mainly favors a direct 4e-reaction pathway for ORR, which is attributed to the well-designed structure, the synergistic effect between Co3O4 and [Formula: see text]-MnO2, and the covalent coupling between the Co3O4-MnO2 and reduced graphene oxide. The role of Co3O4 in Co3O4–MnO2 hybrid for catalyzing ORR also has been illustrated by varying the mass ratio of Co3O4 and MnO2, which reveals that the Co3O4–MnO2 with the ratio of 1:1 has better catalytic activity.

scholarly journals Photocatalytic Degradation of Organic Pollutant using Reduced Graphene Oxide

2019 ◽  
Vol 8 (4S2) ◽  
pp. 870-872
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
Photocatalytic Degradation ◽  
Reduced Graphene Oxide ◽  
Organic Pollutant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Scaning Electron Microscopy

A simple eco friendly preparation of reduced graphene oxide from graphene oxide using strawberry extract is reported. As prepared reduced graphene oxide were characterized by X-Ray Diffraction, UV-Vis spectroscopy, Scaning electron microscopy and degradation performane of MB. The reduced graphene oxide was effectively degradation of MB.

Sign in / Sign up

Export Citation Format

Share Document