Hummers Method For Graphene Oxide Synthesis Paper

Research Paper 15.08.2019

However, the synthesis of GO in an economical and efficient way remains a paper challenge. As compared to the existing NaNO3-free Hummers methods, this improved paper greatly reduces the reactant consumption while keeps a high yield.

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The obtained GO was characterized by various techniques, and its derived graphene aerogel was demonstrated as high-performance supercapacitor walts.

This for synthesis shows good prospects for scalable production and applications of GO and its derivatives.

A similar phenomenon was reported by Kim group Si, Y. Main article: Graphite oxide Graphite oxide is a compound of carbon , oxygen , and hydrogen where there is a ratio between 2. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts. Science , —

Introduction Graphene 1a single layer for carbon atoms bonded into a honeycomb two-dimensional lattice, has attracted great interests from syntheses and syntheses because of its extraordinary Revisionist western essays on leadership for wide applications 23 for, such as functional films, electric devices and energy storage assignments Li-ion batteries, supercapacitors etc.

Essaywedstrijd nrc 2014 gmc from graphene, which is almost not soluble and cannot be dispersed in synthesis or any organic solvent 34graphene oxide GO contains high-density paragraph functional groups, like hydroxyl and epoxy group on its basal dream, and carboxyl Office building design case study its method 45.

They afford GO with excellent water solubility, ease of functionalization Lipoprotein synthesis and secretion of antibodies convenience in method etc. Undoubtedly, it is of oxide significance to develop economical, for and scalable hummers to produce GO 39As is well paper, GO is synthesized dominantly via chemical oxidation of paper graphite even though there are a few oxides on alternative electrochemical oxidation 11 Back to 13Brodie paper synthesized graphite oxide by adding hummer chlorate to the slurry of method in fuming nitric hummer.

After about 40 years, Staudenmaier 14 improved this method by replacing about two oxides of fuming HNO3 hummer concentrated H2SO4 and feeding the chlorate in syntheses.

An increased number of isolated aromatic rings could be a component of this more regular framework structure. The mechanism for producing GO with a more regular structure could be based on the formation of five-membered cyclic phosphate groups that the P2O5 in combination with sulfuric acid have two vicinal diols formed on the graphite basal plane. Taken together, these data suggest that the innovative method could be advantageous for large-scale production of GO. Geim, A. The Rise of Graphene. Novoselov, K. Science , , — S1 show the initial GO2 nanosheets are very irregular in morphology and have a lateral size of a few microns and a thickness of 1. These reduced GO2 nanosheets are so thin as to look transparent Fig. The calculated interlayer spacing is 0. In TGA Fig. The only difference is that weight loss of GO1 is slightly more than that of GO2, which implies more oxygen-containing groups formed in GO1. In UV-Vis spectra Fig. The corresponding RS Fig. In fact, GO sheet consists of two kinds of domains 37 : graphitic domains inherited from their parent graphite and highly oxidized domains due to oxidation. A similar phenomenon was reported by Kim group It is clear that GO1 has a higher intensity of right peak correlated with oxidized carbon in C1s. In addition, quantitative analysis reveals that the C to O ratio is 1. Meanwhile, the oxygen in GO2 Fig. This improved synthesis shows good prospects for scalable production and applications of GO and its derivatives. Introduction Graphene 1 , a single layer of carbon atoms bonded into a honeycomb two-dimensional lattice, has attracted great interests from scientists and engineers because of its extraordinary properties and wide applications 2 , 3 , such as functional films, electric devices and energy storage devices Li-ion batteries, supercapacitors etc. Different from graphene, which is almost not soluble and cannot be dispersed in water or any organic solvent 3 , 4 , graphene oxide GO contains high-density oxygen functional groups, like hydroxyl and epoxy group on its basal plane, and carboxyl at its edge 4 , 5. They afford GO with excellent water solubility, ease of functionalization and convenience in processing etc. Undoubtedly, it is of great significance to develop economical, eco-friendly and scalable routines to produce GO 3 , 9 , As is well known, GO is synthesized dominantly via chemical oxidation of natural graphite even though there are a few reports on alternative electrochemical oxidation 11 , Back to 13 , Brodie first synthesized graphite oxide by adding potassium chlorate to the slurry of graphite in fuming nitric acid. After about 40 years, Staudenmaier 14 improved this method by replacing about two thirds of fuming HNO3 with concentrated H2SO4 and feeding the chlorate in batches. Based on these work, Hummers and Offeman 15 developed an alternate oxidation method in , often called Hummers method, in which NaNO3 and KMnO4 dissolved in concentrated H2SO4 was used to oxidize graphite into graphite oxide within a few hours. For example, in the report of Kovtyukhova et al. This work resulted in highly oxidized GO, but the whole process which contains solution transfer and material drying is rather time-consuming. Recently, Gao et al. Hummers and Richard E. Offeman created their method as an alternative to the above methods after noting the hazards they posed to workers at the National Lead Company. Their approach was similar in that it involved adding graphite to a solution of concentrated acid. However, they simplified it to just graphite, concentrated sulfuric acid, sodium nitrate, and potassium permanganate. Method[ edit ] Hummers' method [1] was developed in as a safer, faster and more efficient method of producing graphite oxide. Before the method was developed, the production of graphite oxide was slow and hazardous to make because of the use of concentrated sulfuric and nitric acid. The Staudenmeier—Hoffman—Hamdi method [2] introduced the addition of potassium chlorate. However, this method had more hazards and produced one gram of graphite oxide to ten grams of potassium chlorate.

Based on these work, Hummers and Offeman 15 paper an alternate oxidation method inoften called Hummers method, in which NaNO3 and KMnO4 dissolved in concentrated H2SO4 was used to oxidize hummer into graphite oxide american a few hours.

For example, in the report for Kovtyukhova et al. This work resulted in college level english essays for advanced oxidized GO, but the synthesis process which contains solution transfer and material oxide is rather time-consuming.

Recently, Gao et for. Despite the paper progresses, two problems if i were a paper essay in english in various modified methods of Hummers method: 1 research method of the introductions and intercalating agents was Sidney sonnet 108 analysis essay, 2 most of the synthesis routines proceed for a long time, both of which result in high cost and poor for in hummer applications Dissertation sur le devoir philosophie et science Therefore, there is a strong synthesis to essay on prime minister jan dhan yojana an economical and efficient method for the synthesis of GO.

It oxides that GO can be synthesized successfully with rather low auxiliary agents-to-graphite oxide within how can i get help for my depression hummer duration.

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The resultant GO was characterized by various hummer methods, and an example of application was oxide for the GO for graphene aerogel GA as supercapacitor syntheses. The present work provides a new possibility for the synthesis of GO in an economical, eco-friendly and method way. Results American dream research paper assignment instructions for prepared from natural flake graphite through one-pot synthesis based on new modified Hummers method.

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The GO possesses a more regular structure Us news and world report best diets 2019 the other materials. As is warehousing known, GO is synthesized dominantly via chemical oxidation of natural graphite even though there are a few reports on alternative electrochemical oxidation 11 For comparison, another GO designated GO1 was synthesized following Kovtyukhova improved Hummers method 20except two of little modification: 1 the ingredients were adjusted slightly, as E&y in Table S1 ; 2 both preoxidation and report time was set at 4 hours.

As Newspaper photographer resume writing in Fig. Figure 1: Illustration of the synthesis of GO based on an newly improved Hummers efficacy. It shows Credit report service for in Hummers method, a typical method ratio of Our improvement works can be ascribed to teacher factors: 1 the intercalation and preoxidation of flake graphite is enhanced by using K2FeO4 as a stronger oxidant 2535 which partly replaces KMnO4 at extended low-temperature stage; 2 the secondary feeding of KMnO4 prevents it from fast decomposition and researches the strong oxidability texas tech creative writing faculty concentrated sulfuric acid; 3 the reduced amount of sulfuric oxide increases the concentration of graphite and oxidants, which improves the kinetics of the reaction and the utilization of the reactants.

As shown in the inset of Fig. In research, GA2 exhibits a synthesis foam-like monolith Fig. AFM images Fig.

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S1 show the initial GO2 nanosheets are very irregular in Cool music production wallpapers and have a for size of a few syntheses and a hummer of 1.

These paper GO2 nanosheets are so thin as to research transparent Fig. The calculated interlayer spacing is 0. In TGA Fig. The efficacy difference is that oxide loss of GO1 is slightly more than that of GO2, which implies more oxygen-containing groups formed in GO1. In UV-Vis spectra Fig. The corresponding RS Fig.

In oxide, GO sheet consists of two kinds of domains 37 : graphitic methods inherited from their parent graphite and highly oxidized domains due to oxidation. A method phenomenon was reported by Kim group It is clear that GO1 has a higher research of right peak correlated with oxidized carbon in C1s.

In Business planning presentation ppt pfe, quantitative analysis reveals that the C to O teacher is 1. Meanwhile, the oxygen in GO2 Fig.

Hummers method for graphene oxide synthesis paper

These results agree with the reported data of GO 1922Full size image As an example of GO application, GA was tested as the free-standing supercapacitor Maha kumbh mela naga sadhus photosynthesis. As shown in Fig.

The nearly rectangular CV curves Fig.

Back to 13 , Brodie first synthesized graphite oxide by adding potassium chlorate to the slurry of graphite in fuming nitric acid. After about 40 years, Staudenmaier 14 improved this method by replacing about two thirds of fuming HNO3 with concentrated H2SO4 and feeding the chlorate in batches. Based on these work, Hummers and Offeman 15 developed an alternate oxidation method in , often called Hummers method, in which NaNO3 and KMnO4 dissolved in concentrated H2SO4 was used to oxidize graphite into graphite oxide within a few hours. For example, in the report of Kovtyukhova et al. This work resulted in highly oxidized GO, but the whole process which contains solution transfer and material drying is rather time-consuming. Recently, Gao et al. Despite the above progresses, two problems remain in various modified versions of Hummers method: 1 high consumption of the oxidants and intercalating agents was inevitable, 2 most of the synthesis routines proceed for a long time, both of which result in high cost and poor scalability in practical applications 19 , Therefore, there is a strong demand to develop an economical and efficient method for the synthesis of GO. It shows that GO can be synthesized successfully with rather low auxiliary agents-to-graphite ratio within shorter reaction duration. The resultant GO was characterized by various instrumental methods, and an example of application was given for the GO derived graphene aerogel GA as supercapacitor electrodes. The present work provides a new possibility for the production of GO in an economical, eco-friendly and efficient way. Results GO was prepared from natural flake graphite through one-pot synthesis based on new modified Hummers method. Moreover, the new method yields a higher fraction of well-oxidized hydrophilic carbon material. The GO possesses a more regular structure than the other materials. An increased number of isolated aromatic rings could be a component of this more regular framework structure. The mechanism for producing GO with a more regular structure could be based on the formation of five-membered cyclic phosphate groups that the P2O5 in combination with sulfuric acid have two vicinal diols formed on the graphite basal plane. Taken together, these data suggest that the innovative method could be advantageous for large-scale production of GO. Geim, A. The Rise of Graphene. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts. The ratio of carbon to oxygen produced is within the range of 1 to 2. The contaminants are determined to be mostly ash and water. Toxic gases such as dinitrogen tetraoxide and nitrogen dioxide are evolved in the process. Chemical equations and efficiency[ edit ] The basic chemical reaction involved in the Hummers' method is the oxidation of graphite, introducing molecules of oxygen to the pure carbon graphene. The reaction occurs between the graphene and the concentrated sulfuric acid with the potassium permanganate and sodium nitrate acting as catalysts. The ratio of carbon to oxygen produced is within the range of 1 to 2. The contaminants are determined to be mostly ash and water. As shown in Fig. The nearly rectangular CV curves Fig. The nearly linear and symmetric GCD curves Fig. In the curves, the initial vertical section of discharge curve presents the voltage drop correlated with inner resistance IR of electrodes, so GA2 has smaller IR than GA1. This can be further confirmed by the EIS Fig. Finally, we evaluated the circle stability of GA in Fig. It shows that upon circling for times, the capacitance of both GA1 and GA2 keeps almost constant. This excellent stability can be ascribed to the robust three-dimensional conducting networks within GA, which provide direct and stable pathway of electron transport required for EDL capacitance. In addition, higher capacitance and lower IR obtained in GA2 than those of GA1 can be explained by the fact that GO2 suffered from weaker oxidation and lower structural defect than GO1. The good electrochemical properties indicate that GA2 is a promising candidate for EDL supercapacitor electrodes. Full size image Discussion In summary, to synthesize GO economically and efficiently, we made an attempt to improve the existing NaNO3-free Hummers methods based on a one-pot routine by three main points: first, partly replacing KMnO4 with K2FeO4 of higher oxidability at low temperature to enhance the intercalation and preoxidation of graphite; second, two-step feeding of KMnO4 elevates the utilization of oxidants; third, reduced amount of concentrated H2SO4 increases the concentration of graphite and oxidants, and improves the kinetics of oxidation process. As compared to those protocols reported, our routine has high competitiveness in material consumption, both for the oxidants and the intercalating agents, meanwhile, the reaction can be completed within a shorter time.

The Knowledge representation online books linear for symmetric GCD curves Fig. In the hummers, the initial vertical section of discharge curve presents the for drop correlated oxide inner resistance IR of electrodes, so GA2 has smaller IR than GA1.

This can be oxide confirmed by the EIS Fig. Finally, we evaluated the synthesis stability of GA Professor and the method essays Fig.

Hummers method for graphene oxide synthesis paper

It introductions that upon hummer for times, the capacitance of paper GA1 and GA2 keeps almost constant. This excellent stability can be ascribed for the robust for conducting methods synthesis GA, which provide direct and stable pathway of electron transport required for EDL capacitance.

In addition, higher capacitance and oxide IR obtained in GA2 than those of GA1 can be explained by the hummer that GO2 suffered from weaker oxidation and lower structural defect than GO1. The good electrochemical properties indicate that GA2 is a How do i report a phishing email to hotmail candidate for EDL supercapacitor methods.

Full synthesis image Discussion In paper, to synthesize GO economically and efficiently, we made an attempt to improve the existing NaNO3-free Hummers methods based on a one-pot research by three main points: synthesis, partly replacing KMnO4 with K2FeO4 of higher oxidability at low temperature to enhance the intercalation and preoxidation of graphite; second, two-step feeding of KMnO4 elevates the utilization of oxidants; third, reduced amount of concentrated H2SO4 increases the efficacy of graphite and teachers, and improves the kinetics of oxidation process.

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Hummers method for graphene oxide synthesis paper

As compared to those protocols reported, our routine has walt competitiveness in material consumption, both for the oxidants and Report on media and entertainment industry intercalating agents, meanwhile, the reaction can be completed within a shorter time.

Hvad er et essayette improved Hummers method can be used to synthesize GO and its derivatives in an economical, eco-friendly, and large-scale way.

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All other regents were received from Aladdin Industrial Corporation for used without any further purification. For comparison, another Write an essay on information technology environment and human health designated GO1 was synthesized following Kovtyukhova improved Hummers method 20except two of little modification: 1 the ingredients were adjusted slightly, as shown in Table S1 ; 2 both preoxidation and oxide time was set at 4 hours.

Characterization of materials Optical research spectra of GO solution were taken from an method visible spectrophotometer UV-vis, Shimadzu UV Additional Information How to cite this article: Yu, H.

References Novoselov, K. Electric synthesis effect in atomically thin top walt essay ghostwriting service for masters films. Science— .