Synthesis of Highly Reduced Graphene Oxide for Supercapacitor

A facile method to synthesize highly reduced graphene oxide in solid phase was developed. The reduced graphene oxide was scarcely prepared in solid phase. Solid substances act as spacers and pillaring agents. Sheets can not be close to each other in reduction process, and sheets agglomeration might not form. After reduction reaction is complete, the spacers and pillaring agents are removed. The average interlayer spacing and surface area of product are bigger than those of reduced graphene oxide. The product has few-layered sheet, and the ratio of carbon to oxygen is high, which might imply that the product is more similar to graphene compared to reduced graphene oxide. The specific capacitance of product is almost three times higher than that of reduced graphene oxide at the same current density.

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Facile Synthesis and Performance of Reduced Graphene Oxide/Cobalt Oxide Composite for Supercapacitor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.779 ◽

2013 ◽

Vol 785-786 ◽

pp. 779-782

Author(s):

Hong Juan Wang ◽

Dong Zhou ◽

Feng Peng ◽

Hao Yu

Keyword(s):

Graphene Oxide ◽

Specific Capacitance ◽

Reduced Graphene Oxide ◽

Cobalt Oxide ◽

Current Density ◽

Chemical Precipitation ◽

Discharge Performance ◽

Reduced Graphene ◽

Subsequent Calcination ◽

And Performance

A series of reduced graphene oxide/cobalt oxide composites (Co3O4/rGO)were fabricated via a chemical precipitation approach and subsequent calcination in Ar atmosphere. Experimental results show that Co3O4/rGO composite with 86 wt% of Co3O4 loading exhibits the optimum specific capacitance of 240 F g-1 in 6.0 M KOH electrolyte at the current density of 0.8 A g-1, excellent quick charge-discharge performance and outstanding cyclic stability with 2.3% of its specific capacitance increase after 2400 cycles at the current density of 8 A g-1 in GCD test, exhibiting significant potential of Co3O4 /rGO composite in the application of supercapacitors.

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Cobalt and copper nanoparticles on partially reduced graphene oxide interlayer spacing carbon nanotubes or carbon black as catalysts for oxygen reduction reaction

Revista Mexicana de Ingeniería Química ◽

10.24275/rmiq/mat961 ◽

2020 ◽

Vol 20 (1) ◽

pp. 67-75

Author(s):

Y.Y. Rivera-Lugo ◽

◽

C. Silva-Carrillo ◽

B. Trujillo-Navarrete ◽

E.A. Reynoso-Soto ◽

...

Keyword(s):

Carbon Nanotubes ◽

Graphene Oxide ◽

Carbon Black ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Reduced Graphene Oxide ◽

Copper Nanoparticles ◽

Interlayer Spacing ◽

Reduction Reaction ◽

Reduced Graphene

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Reduced Graphene Oxide-Supported Cobalt Phosphide Nanoflowers via in situ Hydrothermal Synthesis as Pt-Free Effective Electrocatalysts for Oxygen Reduction Reaction

NANO ◽

10.1142/s1793292018500479 ◽

2018 ◽

Vol 13 (05) ◽

pp. 1850047 ◽

Cited By ~ 3

Author(s):

Yang Lv ◽

Xianbao Wang ◽

Tao Mei ◽

Jinhua Li ◽

Jianying Wang

Keyword(s):

Electron Transfer ◽

Graphene Oxide ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Reduced Graphene Oxide ◽

Current Density ◽

Reduction Reaction ◽

Cobalt Phosphide ◽

Reduced Graphene

Cobalt phosphide (CoP) has aroused extensive research interest in a field of electrochemical application due to its excellent catalytic activities. CoP and its compounds have been widely reported using in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). However, few reports about CoP as electrocatalysts for oxygen reduction reaction (ORR) were presented. In this work, we prepare reduced graphene-oxide(rGO)-loaded CoP (rGO@CoP) as an electrocatalyst for ORR through in situ hydrothermal treatment. The rGO@CoP as ORR catalyst exhibits excellent activities where its onset potential has a positive increase of 129[Formula: see text]mV, and the ORR potential achieves an increase of 330[Formula: see text]mV at a current density of 1.0[Formula: see text]mA[Formula: see text]cm[Formula: see text] compared with that of pure CoP. The current density is also significantly improved with an increase of 0.51[Formula: see text]mA[Formula: see text]cm[Formula: see text] at [Formula: see text]350[Formula: see text]mV, and the Tafel slope has a decrease of 19[Formula: see text]mV dec[Formula: see text]. Further tests show that the electron transfer number of rGO@CoP is 3.66, which is larger than 2.19 of pure CoP, indicating that it is dominated by a four-electron transfer pathway. Moreover, its stability (remained 98.6% current after working 6000[Formula: see text]s) and methanol tolerance are outstanding. These results show that rGO@CoP may be considered to replace traditional Pt-based ORR catalysts for fuel cells, and rGO loading has been proven to be an effective strategy to enhance the ORR performance of CoP, which may provide a new idea to synthesize transition metal phosphides as ORR catalysts.

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Performance of Fast Thermally Reduced Graphene Oxide for Supercapacitor

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.783 ◽

2013 ◽

Vol 785-786 ◽

pp. 783-786 ◽

Cited By ~ 1

Author(s):

Hong Juan Wang ◽

Dong Zhou ◽

Feng Peng ◽

Hao Yu

Keyword(s):

Graphene Oxide ◽

Specific Capacitance ◽

Reduced Graphene Oxide ◽

Current Density ◽

High Specific Capacitance ◽

Thermal Reduction ◽

Exfoliated Graphite ◽

Capacitive Performance ◽

Reduced Graphene ◽

A Current

Graphene with different reduction degrees was prepared by fast thermally reduction of exfoliated graphite oxide (GO) at 200-700 °C. Structure and the electrochemical capacitive performance were characterized and measured. The results show that different thermal reduction temperatures can obtain reduced graphene oxide (rGO) with different reduction degrees and influence the electrochemical capacitive performance. The rGO-400 by thermal treat at 400 °C exhibits a significantly high specific capacitance of 407 F g-1 in 6.0 M KOH electrolyte at a current density of 0.4 A g-1 and outstanding cyclic stability with 96.1% of its origin specific capacitance maintained after 2000 cycles at the current density of 10 A g-1 in GCD test.

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Free-standing reduced graphene oxide (rGO) membrane for salt-rejecting solar desalination via size effect

Nanophotonics ◽

10.1515/nanoph-2020-0396 ◽

2020 ◽

Vol 9 (15) ◽

pp. 4601-4608 ◽

Cited By ~ 1

Author(s):

Pengyu Zhuang ◽

Hanyu Fu ◽

Ning Xu ◽

Bo Li ◽

Jun Xu ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Conversion Efficiency ◽

High Salinity ◽

Interlayer Spacing ◽

Structural Instability ◽

Solar Thermal ◽

Free Standing ◽

Solar Desalination ◽

Reduced Graphene

AbstractInterfacial solar vapor generation has revived the solar-thermal-based desalination due to its high conversion efficiency of solar energy. However, most solar evaporators reported so far suffer from severe salt-clogging problems during solar desalination, leading to performance degradation and structural instability. Here, we demonstrate a free-standing salt-rejecting reduced graphene oxide (rGO) membrane serving as an efficient, stable, and antisalt-fouling solar evaporator. The evaporation rate of the membrane reaches up to 1.27 kg m−2 h−1 (solar–thermal conversion efficiency ∼79%) under one sun, out of 3.5 wt% brine. More strikingly, due to the tailored narrow interlayer spacing, the rGO membrane can effectively reject ions, preventing salt accumulation even for high salinity brine (∼8 wt% concentration). With enabled salt-antifouling capability, flexibility, as well as stability, our rGO membrane serves as a promising solar evaporator for high salinity brine treatment.

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Magnetization of Ultraviolet-Reduced Graphene Oxide Flakes in Composites Based on Polystyrene

Materials ◽

10.3390/ma14102519 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2519

Author(s):

Alexander N. Ionov ◽

Mikhail P. Volkov ◽

Marianna N. Nikolaeva ◽

Ruslan Y. Smyslov ◽

Alexander N. Bugrov

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Reduction Process ◽

X Ray Diffraction ◽

Mesoscopic Structure ◽

Reduced Graphene ◽

Study Results ◽

Edge Defects ◽

Mesoscopic Level ◽

Ferromagnetic Hysteresis

This work presents our study results of the magnetization of multilayer UV-reduced graphene oxide (UV-rGO), polymer matrix (polystyrene), and a conjugated composite based on them. The mesoscopic structure of the composites synthesized in this work was studied by such methods as X-ray diffraction, SEM, as well as NMR-, IR- and Raman spectroscopy. The magnetization of the composites under investigation and their components was measured using a vibrating-sample magnetometer. It has been shown that the UV-reduction process leads to the formation of many submicron holes distributed inside rGO flakes, which can create edge defects, causing possibly magnetic order in the graphite samples under investigation on the mesoscopic level. This article provides an alternative explanation for the ferromagnetic hysteresis loop in UV-rGO on the base of superconductivity type-II.

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Reduced Graphene Oxide-Supported Pt-Based Catalysts for PEM Fuel Cells with Enhanced Activity and Stability

Catalysts ◽

10.3390/catal11020256 ◽

2021 ◽

Vol 11 (2) ◽

pp. 256

Author(s):

Irina V. Pushkareva ◽

Artem S. Pushkarev ◽

Valery N. Kalinichenko ◽

Ratibor G. Chumakov ◽

Maksim A. Soloviev ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Surface Area ◽

Pem Fuel Cells ◽

Polyol Process ◽

Proton Exchange ◽

Active Surface Area ◽

Electrochemical Performances ◽

Simultaneous Reduction ◽

Reduced Graphene

Platinum (Pt)-based electrocatalysts supported by reduced graphene oxide (RGO) were synthesized using two different methods, namely: (i) a conventional two-step polyol process using RGO as the substrate, and (ii) a modified polyol process implicating the simultaneous reduction of a Pt nanoparticle precursor and graphene oxide (GO). The structure, morphology, and electrochemical performances of the obtained Pt/RGO catalysts were studied and compared with a reference Pt/carbon black Vulcan XC-72 (C) sample. It was shown that the Pt/RGO obtained by the optimized simultaneous reduction process had higher Pt utilization and electrochemically active surface area (EASA) values, and a better performance stability. The use of this catalyst at the cathode of a proton exchange membrane fuel cell (PEMFC) led to an increase in its maximum power density of up to 17%, and significantly enhanced its performance especially at high current densities. It is possible to conclude that the optimized synthesis procedure allows for a more uniform distribution of the Pt nanoparticles and ensures better binding of the particles to the surface of the support. The advantages of Pt/RGO synthesized in this way over conventional Pt/C are the high electrical conductivity and specific surface area provided by RGO, as well as a reduction in the percolation limit of the components of the electrocatalytic layer due to the high aspect ratio of RGO.

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