Synthesis, fabrication of graphene oxide membranes, and controlling their diffusion by thermal reduction by abdulrahman alhadhrami a thesis presented to the university of waterloo in fulfillment of the thesis requirement for the degree of doctor of philosophy in chemistry waterloo, ontario, canada, 2016 abdulrahman alhadhrami 2016. The experiments were carried out at a pressure of 4. It has been further reduced by hydrazine hydrate by hydrothermal method to form reduced go rgo. No reaction path was found for the hydrazine mediated reductions of the hydroxyl, carbonyl, and carboxyl groups of go. The conductance change of the networks upon exposure to trace levels of vapor is measured as a function of the chemical reduction. Frontiers advances in microwaveassisted production of. However, no obvious diffraction peaks of graphene oxide were observed, which indicated that most of the oxygencontaining groups of graphene oxide that were reduced by hydrazine hydrate disappeared. Synthesis of graphene oxide using modified hummers method. Three mechanisms were identified as reducing epoxide groups of go with hydrazine as a reducing agent. We have performed an experimental investigation on the effects of hydrazine treatment on graphene oxide via a reactionmodel approach. We report the synthesis and structural transformation of fcc to hcp in nigraphene nigr composite by simple chemical route via sonication.
Highlevel supercapacitive performance of chemically reduced. The synthesis approach requires a simultaneous reduction of palladium and copper nitrates in presence of graphene oxide go nanosheets using hydrazine hydrate as a strong reducing agent. A reduced graphene oxideplatinumii tetraphenylporphyrin nanocomposite rgopt. Kinetics of hydrazine reduction of thin films of graphene. Some reported examples of graphene oxide reduction include. Pdf charge transport mechanism of hydrazine hydrate reduced. The density functional theory method m052x631gd was used to investigate reaction mechanisms for deoxygenation of graphene oxides gos with hydrazine or heat treatment. The results showed that chemical reduction of graphene oxide was achieved using hydrazine hydrate as a reducing agent and the rgo was well dispersed in the shwpu matrix. Ruoff3 1department of chemical engineering, cheju national university, cheju 690756, republic of korea 2department of chemical engineering, university of texas, austin, texas 787, usa 3department of mechanical engineering, university of texas, austin, texas 787, usa.
Journal of nanoparticles hindawi publishing corporation. Reaction mechanisms, product structures, and reaction design xingfa gao, joonkyung jang, and shigeru nagase, department of theoretical and computational molecular science, institute for molecular science, myodaiji. Chapter 3 synthesis of graphene oxide and reduced graphene oxide. These graphene oxide networks are tunably reduced toward graphene by varying the exposure time to a hydrazine hydrate vapor. We also reduced go by a conventional reducing agent, hydrazine hydrate n2h4. But much higher amount of graphene oxide can leads to incomplete reduction and thus bad quality final product.
Preparation of graphene from chemical reduction of graphene oxide go is recognized as one of the most promising methods for largescale and lowcost production of graphenebased materials. We prepared hydrazinereduced materials from both graphite oxide go particles, which were not exfoliated, and completely exfoliated individual graphene oxide platelets, and then analyzed their chemical and structural properties by elemental analysis, xps, tga, xrd, and sem. The results indicated that the graphene ratio played an important. After sonication, 400 ml go solution 5 mgml was transformed in situ into graphene under stirring by adding 2 ml hydrazine hydrate 50% and 5 ml ammonia solution 25% into the solution according to a modified wallaces method. Hydrazinereduction of graphite and graphene oxide request pdf.
The prepared shwpurgo nanocomposites were further treated under heating, microwave radiating, and electrifying conditions to investigate their healing property. Pdf synthesis and characterization of reduced graphene oxide. In this paper, graphite oxide was prepared from natural flake graphite by hummers method through liquid oxidization, and the reduced graphene oxide was obtained by chemical reduction of graphene oxide using nh 3 ch 2 o aqueous solution and hydrazine hydrate. Additionally, an n component has been found in materials that are produced by reduction of graphene oxide with hydrazine nh 2 nh 2. Ruoff3 1department of chemical engineering, cheju national university, cheju 690756, republic of korea.
Graphene oxide go was successfully prepared by a modi. Here, we compare the deoxygenation efficiency of graphene oxide suspensions by different reductants sodium borohydride, pyrogallol, and vitamin c, in. Synthesis and characterization of graphene oxide go and. The raw material graphite, graphite oxide, and reduced graphene oxide were.
The reduction effect and mechanism of the asprepared go reduced with hydrazine hydrate at different temperatures and. Reduction of go with hydrazine hydrate at 80c for 1 hour to remove carbonyl and hydroxyl functionality. Comparative studies on singlelayer reduced graphene oxide. Temperature dependence of graphene oxide reduced by hydrazine. Chemical reduction of graphene oxide can be used to produce large. The morphology, diameter, stability and uvvis absorbance of reducedngo were detected firstly. Facile synthesis of graphene via reduction of graphene oxide by. Although the chemical structures and reaction mechanisms associated with these n species in reduced graphene oxide are not yet understood, it is thought that the n atoms come from hydrazine during reduction.
Original article the preparation of reduced graphene oxide. Metallated porphyrin noncovalent interaction with reduced. Synthesis, fabrication of graphene oxide membranes, and. Xray photoelectron spectroscopy xps was used for the characterization of graphene oxide and the reduced graphenes.
However, the challenge is to synthesize graphene in a bulk quantity. Temperature dependence of graphene oxide reduced by. Synthesis of graphene oxide using modified hummers method and. The variation of the contents of carbon in carbon and oxygen functional groups. The preparation of solutionprocessable graphene from graphite oxide typically involves a hydrazine reduction step, but the use of such a reagent in the largescale implementation of this approach is not desirable due to its high toxicity. In this paper, graphite oxide was prepared from natural flake graphite by hummers method through liquid oxidization, and the reduced graphene oxide was obtained by chemical reduction of graphene oxide using nh 3 h 2 o aqueous solution and hydrazine hydrate.
Research institute of photocatalysis, fujian provincial key laboratory of photocatalysisstate key laboratory breeding base, fuzhou university, fuzhou 350002, china2. Hydrazine hydrate reduction method was used to reduce graphene oxide ngo. Hydrazinereduction of graphite and graphene oxide sungjin park a,b, jinho an a, jeffrey r. Hydrazine is a twoelectron reducing agent whereas nitro group is a fourelectron reduction process. The preparation of reduced graphene oxide rgo by chemical reduction of. Vitamin c is an ideal substitute for hydrazine in the. For the optimum reduction of the go, optimum quantity of hydrazine hydrate is needed. Advances in microwaveassisted production of reduced graphene.
Hydrazine monohydrate may be used as a reducing agent for the reduction of. Hydrazine hydrate, reagent grade, n2h4 5060 % nh2nh2. Xrd images reveal crystalline structure for both go and rgo. Ruoff a, a department of mechanical engineering and the texas materials institute, the university of texas at austin, one university station c2200, austin, tx 787120292, usa b department of chemistry, inha university, incheon 402751, republic. Much higher concentration of zinc acetate will lead to bigger particles of zinc oxide in the final composite. Colloidal dispersions of graphene oxide sheets in water at a concentration of 5 mgml were obtained. Synthesis of reduced graphene oxide rgo from graphene oxide. The reduction of graphene oxide can be achieved a number of ways through thermal, chemical, or electrochemical methods. We prepared hydrazinereduced materials from both graphite oxide go particles, which were not exfoliated, and completely exfoliated. Hydrazine hydrate acts as the reducing agent in synthesis method. Apr 15, 2014 preparation of graphene from chemical reduction of graphene oxide go is recognized as one of the most promising methods for largescale and lowcost production of graphene based materials. Preparation of graphene from chemical reduction of graphene oxide go is recognized as one of the most promising methods for largescale and lowcost production of graphene based materials. Nitroarenes in the presence of hydrogen peroxide functionalized carbon nanotubes. We prepared hydrazinereduced materials from both graphite oxide go particles, which were not exfoliated, and completely exfoliated individual graphene oxide platelets, and then analyzed their.
The comparison between two kinds of singlelayer reduced graphene oxide rgo sheets, obtained by reduction of graphene oxide go with the electrochemical method and hydrazine vapor reduction, referred to as ergo and crgo, respectively, is systematically studied. We prepared hydrazine reduced materials from both graphite oxide go particles, which were not exfoliated, and completely exfoliated individual graphene oxide platelets, and then analyzed their chemical and structural properties by elemental analysis, xps, tga, xrd, and sem. Although there is no morphology difference between the ergo and crgo films adsorbed on solid substrates observed by. Hydrazine hydrate used as reducing agent to prepare for the reduced graphene oxide rgo. Feb 04, 2011 temperature dependence of graphene oxide reduced by hydrazine hydrate. Graphene oxide was prepared through hummers method,then different reduced graphenes were prepared via reduction of graphene oxide with hydrazine hydrate for 1h. Graphene has attracted great interest for its excellent mechanical, electrical, thermal and optical properties. To investigate the preparation of reduced graphene oxide reducedngo and its photothermal therapy of gliomas in vivo and in vitro. To obtain good quality of gr, reduction process was performed in following two steps. In this work graphene oxide was prepared by oxidizing graphite to form graphite oxide. No reaction path was found for the hydrazinemediated reductions of the hydroxyl, carbonyl, and carboxyl groups of go. Hydrazine hydrate has been used for the deproteination of the enamel samples in a study. No remarks on what actually happened to the hydrazine were given in this article. Application of hydrazine hydrate in the synthesis of octa.
The effect of synthesized nanostructures, including graphene oxide, chemically reduced graphene oxide with sodium dodecyl sulfate sds, chemically reduced graphene oxide with polyvinylpyrrolidone, and multiwalled carbon nanotubes, on the kinetics of methane hydrate formation was investigated in this work. Chemical reduction of graphene oxide by a mild and. We prepared hydrazine reduced materials from both graphite oxide go particles, which were not exfoliated, and completely exfoliated individual graphene oxide platelets, and then analyzed their. Reducing graphene oxide to produce reduced graphene oxide hitherto referred to as rgo, is an extremely vital process as it has a large impact on the quality of the rgo produced, and therefore will determine how close rgo will come, in terms of structure, to pristine graphene. Hydrazine can be monoprotonated to form various solid salts of the hydrazinium cation n. Synthesis and characterization of graphene oxide go and reduced graphene oxide rgo for gas sensing application. Hydrazine was reacted with small conjugated aromatic compounds containing various oxygen functional groups to mimic the structure of graphene oxide. The raw material graphite, graphite oxide, and reduced graphene oxide were characterized by xray diffraction.
Hydrazine is the most common and effective reducing agent used to convert graphene oxide go to reduced graphene oxide rgo via hydrothermal treatment. The reduction effect and mechanism of the asprepared go reduced with hydrazine hydrate at different temperatures and time were characterized by xray photoelectron spectroscopy xps, fourier transform infrared spectroscopy ftir, elemental analysis ea, xray diffractions xrd, raman spectroscopy. Temperature dependence of graphene oxide reduced by hydrazine hydrate. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. Pdf effect of nitrogen doping on the structural and the. Key laboratory for soft chemistry and functional materials of ministry education, nanjing university of science and technology, nanjing 210094, china. Reduced graphene oxide as catalyst for hydrogenation of. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Kinetics of hydrazine reduction of thin films of graphene oxide and the determination of activation energy by the measurement of electrical conductivity.
Charge transport mechanism of hydrazine hydrate reduced. Go was prepared by exfoliation of graphite using modified hummers method and then reduced using hydrazine hydrate reducing agent to produce rgo. Synthesis of reduced graphene oxide rgo to obtain reduced graphene oxide, hydrazine hydrate was used as the reducing agent. Chemical structures of hydrazinetreated graphene oxide and. The highly active and recyclable catalyst has many advantages including mild reaction conditions. The hydroxyl and carboxylic groups were not readily removed while carbonyl groups reacted with hydrazine to form the corresponding hydrazone complexes.
It can be produced by micromechanical exfoliation of highly ordered pyrolytic graphite, epitaxial growth, chemical vapor deposition, and the reduction of graphene oxide go. Jan 24, 2012 in the 1960s, hydrazine nh 2 nh 2 was used to chemically reduce thin graphite oxide go particles 1,2. The chemical reduction of graphene oxide can provide large quantities of reduced graphene oxide for potential application in electronics and composite materials. Green preparation of reduced graphene oxide for sensing. Although there is no morphology difference between the ergo and crgo films adsorbed on solid substrates observed by afm, the.
Strong reducing reagents have been widely used to reduce graphene oxide. The preparation of composite material of graphene oxide. In the 1960s, hydrazine nh 2 nh 2 was used to chemically reduce thin graphite oxide go particles 1,2. Synthesis and characterizations of graphene oxide and reduced. The maximally oxidized bulk product is a yellow solid with c.
Reducing graphene oxide to produce reduced graphene oxide hitherto referred to as rgo, is an extremely vital process as it has a large impact on the quality of the rgo produced, and therefore will determine how close. Pdf the reduction of graphene oxide with hydrazine. Potts a, aruna velamakanni a, shanthi murali a, rodney s. Synthesis and characterization of reduced graphene oxide. Graphene oxide go was successfully prepared by a modified hummers method. Xray photoelectron spectroscopy study on reduction of. The methods which are capable of producing the highest quality graphene tend to be more complex. The syntheses of nigr composite by simultaneous reduction method, and the effect of different composition ratio on morphology and crystal structure were examined in our present study. Synthesis and characterization of reduced graphene oxide rgo. Preparation of graphene from chemical reduction of graphene oxide go is recognized as one of the most promising methods for largescale and. Kinetic study of methane hydrate formation in the presence. In the present investigation, go was prepared by exfoliation of graphite using modified hummers method and then reduced using hydrazine hydrate. Raman spectra of go and rgo suggest the formation of dband and gband at 60 and 1590 cm. A new approach to synthesize graphene is oxidizing graphite powder with a mixture of h 2 so 4 h 3 po 4 acids and potassium permanganate.
This study reports a new, green, and efficient reducing agent caffeic acidca for go reduction. The addition of hydrazine hydrate to reduced graphene oxide rgo counter electrode improves its performance in dyesensitized solar cells dssc. During this time, the reduction product precipitated as a black solid. Xrd, fesem, raman, ftir spectrophotometer and tga were used for characterization of go and rgo. Chemically assisted graphene oxide go is synthesised by improved hummers method.
Hydrazine monohydrate n2h4 6465 %, reagent grade, 98%. Green preparation of reduced graphene oxide for sensing and. Ruoff a, a department of mechanical engineering and the texas materials institute, the university of texas at austin, one university station c2200. Tpp nanocomposite was successfully prepared via noncovalent. For example, hydrazine hydrate enabled reduction of graphene oxide in the oil bath for 12 h and 24 h resulted in a co ratio about 5 park et al. Pdf chemically assisted graphene oxide go is synthesised by improved hummers method. Study of reduced graphene oxide preparation by hummers. It may be used as a reducing agent in the following. Partial reduction can be achieved by treating the suspended graphene oxide with hydrazine hydrate at 100 c for 24 hours, by exposing graphene oxide to hydrogen plasma for a few seconds, or by exposure to a strong pulse of light, such as that of a xenon flash. Dec 18, 2017 in the present investigation, go was prepared by exfoliation of graphite using modified hummers method and then reduced using hydrazine hydrate reducing agent to produce rgo.
Chemical structures of hydrazinetreated graphene oxide. By using hydrazine hydrate, the epoxy group in graphite oxide was reduced then the solution of reduced graphite oxide rgo is exfoliated. Synthesis of reduced graphene oxide rgo via chemical reduction. The first three methods can produce graphene with a. Ruoff and coworkers 3 developed the use of hydrazine to reduce individual graphene oxide. Ftir spectra of graphene oxide gro, pemediated highly. Potts and aruna velamakanni and shanthi murali and rodney s. A lowtemperature method to produce highly reduced graphene oxide.