Synthesis of the Exfoliated Graphite from Graphite Oxide

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.

scholarly journals Influence of external heating rate on the structure and porosity of thermally exfoliated graphite oxide

Carbon ◽  
2017 ◽  
Vol 111 ◽  
pp. 651-657 ◽  
Author(s):  
Yang Qiu ◽  
Samuel Moore ◽  
Robert Hurt ◽  
Indrek Külaots
Keyword(s):  
Heating Rate ◽  
Graphite Oxide ◽  
Exfoliated Graphite ◽  
External Heating ◽  
Thermally Exfoliated Graphite

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

RSC Advances ◽  
2016 ◽  
Vol 6 (50) ◽  
pp. 44717-44722 ◽  
Author(s):  
Xiaoming Sun ◽  
Peng Liu ◽  
Yi Gu ◽  
Thomas E. Rufford ◽  
X. S. Zhao
Keyword(s):  
Composite Materials ◽  
Graphite Oxide ◽  
Crystalline Phase ◽  
Manganese Oxides ◽  
Composite Electrodes ◽  
Oxide Composite ◽  
Hummers Method ◽  
Modified Hummers Method

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.

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

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.

Study of Ozone Decomposition Using TiO2-Graphene Composites

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.

scholarly journals Self-Photoluminescence of Unzipped Multi-Walled Carbon Nanotubes

Nanomaterials ◽  
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.

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

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.

Note. Antimicrobial Effect of Pressurized Carbon Dioxide on Yersinia enterocolitica in Broth and Foods

2001 ◽  
Vol 7 (3) ◽  
pp. 245-250 ◽  
Author(s):  
O. Erkmen
Keyword(s):  
Carbon Dioxide ◽  
Yersinia Enterocolitica ◽  
Exposure Time ◽  
Slow Rate ◽  
Antimicrobial Effect ◽  
Antimicrobial Effects ◽  
Temperature Exposure ◽  
D Values ◽  
Two Stages ◽  
D Value

Antimicrobial effect of 15, 30 and 60 atm CO 2 pressures was studied on Yersinia enterocolitica at 25, 35 and 45 °C. Two stages were observed in the destruction curves. The earlier stage was characterized by a slow rate of inactivation in number of Y. enterocolitica, which increased sharply at the later stage. An increase of pressure and/or temperature enhanced the antimicrobial effects of CO 2. The D values of 6.1 and 4.9 min were obtained for Y. enterocolitica at 45 °C under 15 and 30 atm CO 2 pressure, respectively, while only 1.3 min D value was found at 60 atm. A rapid and significant ( p < 0.05) reduction was obtained in the number of Y. enterocolitica at treated pressures and temperatures. Pressure, temperature, exposure time, and the suspending medium influenced the inactivation rates of Y. enterocolitica.

scholarly journals High-temperature Inhibition of Flowering of Phalaenopsis and Doritaenopsis Orchids

HortScience ◽  
2009 ◽  
Vol 44 (5) ◽  
pp. 1271-1276 ◽  
Author(s):  
Linsey A. Newton ◽  
Erik S. Runkle
Keyword(s):  
High Temperature ◽  
Exposure Time ◽  
Flowering Plants ◽  
Night Temperature ◽  
High Temperature Exposure ◽  
Plant Leaf ◽  
Potted Plants ◽  
Temperature Exposure

Phalaenopsis orchids require a day temperature of 26 °C or less to initiate inflorescences, whereas the night temperature has little or no effect on inflorescence initiation. We determined the duration of high temperature required each day to prevent inflorescence initiation of four Phalaenopsis and Doritaenopsis clones. In Years 1 and 2, mature potted plants were grown in separate greenhouse sections with five daily durations at 29 °C: 0, 4, 8, 12, or 24 h. The high temperature was centered in the 16-h photoperiod (0600 hr to 2200 hr) and the remainder of the day was at 20 °C. Exposure to 29 °C for 8 h or longer inhibited inflorescence initiation of Phalaenopsis Miva Smartissimo × Canberra ‘Mosella’ and Phalaenopsis Brother Pink Mask × Brother Success ‘Explosion’, but Phalaenopsis Baldan's Kaleidoscope ‘Golden Treasure’ and Doritaenopsis ‘Newberry Parfait’ required exposure to 29 °C for 12 h or longer to inhibit inflorescence initiation. Flowering was completely suppressed only when high-temperature exposure time was continual for Doritaenopsis ‘Newberry Parfait’ and Phalaenopsis Baldan's Kaleidoscope ‘Golden Treasure’ and 12 h for Phalaenopsis ‘Mosella’. Plant leaf span generally increased as duration of exposure to 29 °C increased, but high-temperature exposure had few or no significant effects on flowering characteristics of flowering plants. These studies indicate that as few as 8 h of high temperature can prevent flowering of some Phalaenopsis hybrids, whereas others require greater than 12 h of high-temperature exposure.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

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