Control over the morphology and phase of MnOx formed in the modified Hummers' method and impact on the electrocapacitive properties of MnOx–graphite oxide composite electrodes

The controllable morphology and crystalline phase of manganese oxides formed in the Hummer's method have an impact on the electrocapacitive performance of the resulting composite materials.

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Anodic Aqueous Electrophoretic Deposition of Graphene Oxide on Copper Using Different Cathode Materials

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1008.21 ◽

2020 ◽

Vol 1008 ◽

pp. 21-27

Author(s):

Essam Hares ◽

Ahmed Hassan El-Shazly ◽

Marwa Farouk El-Kady ◽

Kholoud Madih ◽

Hamdiya Orleans-Boham ◽

...

Keyword(s):

Graphene Oxide ◽

Electrophoretic Deposition ◽

Graphite Oxide ◽

Cathode Materials ◽

Aqueous Suspension ◽

Graphite Powder ◽

Liquid Exfoliation ◽

Hummers Method ◽

Oxide Deposition ◽

Modified Hummers Method

The effect of four different cathode materials on the anodic deposition of graphene oxide (GO) nanosheets was studied experimentally. First, synthesis of graphite oxide from graphite powder was done by modified Hummers' method. Ultrasonic technique was adopted for the preparation of the stable aqueous suspension of GO by using liquid exfoliation of graphite oxide. Deposition of GO coating on copper sheets (the anode) was done via electrophoretic deposition (EPD) at the same operating condition (5V, 2 min, concentration of 0.5 mg/ml of GO per deionized water) with different cathode materials (copper, stainless steel, aluminum and graphite). The coatings’ morphological and microstructure were investigated using scanning electron microscope (SEM) and the effect of the current density in the EPD process was obtained. The change in the deposition weight was also measured. It was ascertained that the cathode’s material is a major factor can affect the GO’s EPD process and the characteristics of the final coating.

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Study of Ozone Decomposition Using TiO2-Graphene Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.716-717.102 ◽

2014 ◽

Vol 716-717 ◽

pp. 102-107

Author(s):

Xin Tan ◽

Qian Qian Shang ◽

Si Yu Wang

Keyword(s):

Titanium Dioxide ◽

Graphite Oxide ◽

Sol Gel ◽

Graphite Powder ◽

Light Irradiation ◽

Tetrabutyl Titanate ◽

Ozone Decomposition ◽

Initial Concentration ◽

Hummers Method ◽

Modified Hummers Method

Graphene (Gn) were prepared by reduction of graphite oxide (GO), which was obtained from oxidation of graphite powder by a modified Hummers method. The composite of titanium dioxide/graphene (TiO2/Gn) was synthesized using tetrabutyl titanate and GO as the precursors by a sol-gel method. The ozone photodecomposition efficiency of TiO2/Gn was operated under ultraviolet-visible (UV-Vis, λ>365nm) light irradiation. Results showed that as-prepared TiO2/Gn composite exhibited photodecomposition efficiency of 66.12% under UV-Vis light irradiation 1h with the initial concentration of 0.150ppm-0.200ppm, preliminary larger than that of pure TiO2(25.95%), self-photolysis of ozone without photocatalysts (1.33%). The effects of initial concentration of ozone and photodecomposition mechanism were discussed.

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Synthesis of the Exfoliated Graphite from Graphite Oxide

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1085.171 ◽

2015 ◽

Vol 1085 ◽

pp. 171-175

Author(s):

Alexander Bannov ◽

Anastasya Timofeeva ◽

Stepan Yusin ◽

Ksenya Dyukova ◽

E.A. Maximovskiy ◽

...

Keyword(s):

Heating Rate ◽

Exposure Time ◽

Process Parameters ◽

Graphite Oxide ◽

Exfoliated Graphite ◽

Synthesis Process ◽

Hummers Method ◽

Temperature Exposure ◽

Modified Hummers Method

This article is devoted to investigation of the synthesis process of exfoliated graphite. Exfoliated graphite was obtained from graphite oxide using thermal exfoliation. Graphite oxide samples were synthesized using modified Hummers method. The influence of the synthesis process parameters such as heating rate, temperature, exposure time on the properties of graphite oxide were investigated. The as-received exfoliated graphite were tested as electrode for supercapacitors. The capacitance of the supercapacitors based on exfoliated graphite varied in a range of 17-129 F/g.

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Self-Photoluminescence of Unzipped Multi-Walled Carbon Nanotubes

Nanomaterials ◽

10.3390/nano11071632 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1632

Author(s):

Mengyao Chen ◽

Xiaohua Qi ◽

Wenna Zhang ◽

Na Yang ◽

Di Yang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Band Gap ◽

Hummers Method ◽

Light Region ◽

Munk Function ◽

Pristine Cnts ◽

Multi Walled Carbon Nanotubes ◽

Walled Carbon Nanotubes ◽

Modified Hummers Method ◽

Etching Effect

Unzipping of carbon nanotubes (CNTs) has been widely explored to obtain new nanocarbon structures with promising properties. In this work, we report that unzipping of CNTs according to the well-established modified Hummers method produces unzipped CNTs (uCNTs) that exhibit self-photoluminescence that depends on the diameter of pristine CNTs. The uCNTs were characterized using FTIR spectroscopy, XRD, XPS, and Raman spectroscopy indicating that unzipping is accompanied by the introduction of defects and oxygen-containing functional groups. The morphology of CNTs and uCNTs was determined by TEM showing longitude unzipping of CNTs. Our study shows that increasing the diameter of pristine CNTs results in decreasing the edge etching effect and decreasing the functionality of uCNTs. Based on the UV-Vis spectra, the band gap of uCNTs was calculated using the Kubelka–Munk function. The band gap of uCNTs increased with decreasing diameter of pristine CNTs. The uCNTs exhibited photoluminescence with a good emission in the visible light region. The uCNTs with the largest band gap and the highest oxygen content had the strongest fluorescence intensity. Moreover, different metal ions produced different degrees of fluorescence quenching for uCNT-15, which verified the self-photoluminescence of uCNTs.

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Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.324.87 ◽

2021 ◽

Vol 324 ◽

pp. 87-93

Author(s):

Mohamed Adel ◽

Abdel Hady A. Abdel-Wahab ◽

Ahmed Abdel-Mawgood ◽

Ahmed Osman Egiza

Keyword(s):

Raman Spectroscopy ◽

Graphene Oxide ◽

Acidic Solution ◽

Cost Effective ◽

Sem Analysis ◽

Visible Spectroscopy ◽

Sem Images ◽

Hummers Method ◽

Uv Visible ◽

Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

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