Uvvis spectroscopy absorbance mode is the most commonly used. Preparation of waterdispersible graphene by facile. Original article the preparation of reduced graphene oxide. Uv vis spectrum for graphene oxide and graphene uvvis spectra of go figure 2 before and after irradiation at 35 kgy, shows that there are two absorption peak which appears at 292 nm and 237 nm. Graphite oxide uvvis spectrum reveals two new absorbance peaks at 312 nm and 361 nm in addition to the graphene oxide and graphene dispersion peaks. Graphene oxideiron oxide nanocomposites for water remediation. Over the span of years, improvements over various synthesis methods of graphene are constantly pursued to provide safer and more effective alternatives. Figure 2a, indicates that go and ngo have an absorption band at. Graphene oxide go was reduced by a rapid, effective and ecofriendly electrochemical method of repetitive cathodic cyclic potential cycling, without using any reducing reagents. Dispersions of fewlayer layers, multilayer 410 layers and thicklayer 10 layers graphene oxide go were prepared by a modified hummers method with different mass ratios of kmno4 to graphite. Goqd resulted as a better support than rgoqd because of the presence of higher functional. High yield controlled synthesis of nanographene oxide by. Goqd and rgoqd were used as supporting agents for the in situ generation of gold nanoparticles, avoiding the use of additional stabilizers.
The structure of graphene oxide was generally the same as graphene except for some oxygencontaining functional groups, such as epoxy group, hydroxyl and carboxyl 69. As much concentration we take initially, that much amount rgo we get at the end of the process. Uvvis spectra show that rgo has much higher optical adsorption than go in both the uv and visible ranges, consistent with their colors shown in b. Uvvis spectroscopy measurements were performed to determine the extent of sp2. Pdf comparison on graphite, graphene oxide and reduced. The first main ingredient for the synthesis of rgozno composite is graphene oxide. Please reduce the thickness of film or dilute the go in case you are using cuvette. Characterization of graphene oxide and reduced graphene.
Insets of digital images of goqds under excitation of 365 nm. Pure graphite oxide showed a strong absorption peak at 230 nm which shifted to 262 nm in ansg, suggesting the restoration of electronic conjugation within the graphene sheets 9. As the colloid is titrated with naohhcl, the ensuing change in. In the present study, the mcn was modified by reduced graphene oxide rgo that was synthesized via a novel photocatalytic reduction method with different ratios of go to mcn to produce rgomcn composites. Synthesis of graphene oxide go by modified hummers. Preparation and characterization of graphene oxide. However, the development of ngo is severely hindered because of the difficulty in controlled mass production. The strong quantum confinement effect as well as abundant edges and oxygen functional groups enable nanographene oxide ngo a variety of intriguing applications such as catalysis, bioimaging, drug delivery and photovoltaic devices. Ultravioletvisible spectra were recorded for aqueous solutions of graphite oxide by using uv1800, shimadzu spectrophotometer. However, the generation of graphene layers from graphite is quite expensive, but can be achieved at lower cost via controlled oxidation of graphite.
Graphene oxide flakes with a low oxidation degree and decorated with iron oxide have been obtained in one. The electrochemically reduced graphene oxide ergo was characterized by uvvis, eis and zetapotential measurements. Ultravioletvisible uvvis spectroscopic data show that fewlayer go dispersions can be distinguished from multi and thicklayer dispersions by a more intense peak at 230 nm. To our knowledge these peaks were not observed before. Dispersions containing fewlayer layers go can be distinguished from those containing multilayer 410 layers and thicklayer 10 layers go by the intense peak in their uvvis spectra at 230 nm. The fast electronhole recombination in mesoporous carbon nitride mcn photocatalyst has spurred a great interest to improve its efficiency with addition of various modifiers. Controlled synthesis, characterization and reduction of graphene. The strong peak at corresponds to an interlayer spacing of about 0. Doping nanoparticles doping nanoparticles onto graphene or go has been done for the following works brenner, 2012. The prepared graphene oxide and reduced graphene oxide were characterized by uvvisible spectroscopy, ftir spectroscopy, and xrd.
Noncolvalent functionalization of graphene with end. Graphene oxide go layers are the individual sheets of conventional graphite oxide cgo synthesized from graphene. Femtosecond laser interaction with graphene oxide aqueous. The structural and optical properties of the asprepared go nanosheets were characterized by raman, ftir, uvvis and photoluminescence spectroscopy. Analysis was performed successfully using fourier transform. Onepot green synthesis of highly reduced graphene oxide. Controlled synthesis, characterization and reduction of. Sandhya murali et al international journal of chemtech research, 2018,1103. Synthesis, characterization, chemical reduction and biological application of graphene oxide by xiguang gao a thesis presented to the university of waterloo. Graphene and graphite oxide have gained vast popularity and become wonder materials in the present context of research and development. Research article preparation and characterization of graphene oxide jianguosong, 1 xinzhiwang, 1 andchangtangchang 2 college of environment and materials engineering, yantai university, qingquan road, laishan district, yantai, china. Ultravioletvisible spectroscopy of graphene oxides aip publishing.
Graphene oxide go has recently attracted great attention due to its unique chemical and physical properties. Both graphene oxide and reduced graphene oxide were characterized by uvvisible spectroscopy, ftir spectroscopy, and xrd techniques. Pdf ultravioletvisible spectroscopy of graphene oxides. Xrdhta, uv visible, ftir and sem interpretation of reduced. Comparison of the aqueous dispersion of graphite oxide and ansg are shown in the. Uvvisible spectra recorded in distilled water at different reaction time. Reduced graphene oxidemesoporous carbon nitride as. The preparation of graphene oxide was controlled by reaction temperature, reaction time and concentration of kmno 4. Graphene oxide go and reduced graphene oxide rgo are known to have superior properties for various applications. For clarity, c 1 s and o 1 s spectra and their fits are shown after shirley background subtraction and vertically offset from the fitting components. Thermal decomposition and coprecipitation 33 figure 18. Uvvis absorption spectra of go aqueous dispersions before 1 and after.
Figure 3 shows the uvvis absorption spectra for go, agrgo and agrgoaa composites. Uvvis diffuse reflectance spectroscopy uvvis drs using a uvvis spectrophotometer cary500, varian co. Synthesis and characterization of iron oxide nanoparticle. Sonochemical preparation of functionalized graphenes. Graphene oxide and nanographene oxide optical properties uvvis absorbance spectra and photoluminescence emission were obtained. Ultravioletvisible spectroscopy of graphene oxides. A simple ozone bubbling procedure for the preparation of. Figure 2 optical properties of nanographene oxide sheets. The absorption peak at 292 nm which indicates n transitions of co. Uv vis absorption spectra of as prepared graphene oxide dispersed in different four solvents by means of bath sonication.
Uv visible spectrums obtained as a result of laser irradiation and mixing go with ammonia. Uvvisible spectroscopy the optical characterization of the sample was recorded on uvvis absorption spectrophotometer figure 4 a shows the uvvisible absorption spectra of zno. The room temperature uvvis absorption spectra of znonps are shown in figure 4. Nanographene oxide for cellular imaging and drug delivery. Graphene oxide quantum dots as the support for the. The purpose of this work is the structural analysis of graphene oxide go and by means of a new structural model to answer the questions arising from the lerfklinowski and the lee structural models. In this work, the go nanosheets were prepared by a chemical exfoliation technique. Sem images for a asprepared go and b irradiated rgo 10 figure 23.
The optical absorption spectra was recorded by using shimadzupharmaspec17000 uvvis. K2feo4 fevibased compound, obtained from a dry synthesis, has been used as a green oxidant of graphite to produce graphene oxide, avoiding the use of the toxic permanganates. All answers 18 uvvis absorption spectra of graphene oxide should have peak at about 230 nm related to transitions of the aromatic cc bond and a shoulder at about 300 nm correspond to n. Research article aqueous colloidal stability of graphene. In this way, the water solubility of graphene was enhanced. Facile reduction of graphene oxide suspensions and films. Xrdhta, uv visible, ftir and sem interpretation of. Synthesis, characterization, chemical reduction and. On the other hand, ccg, or partially reduced colloid of graphene oxide, uses the remnant oxygencontaining groups for displaying the stability of mildly oxidised graphene oxide sheets. The xrd patterns of graphite oxide in figure 2, showed that a strong diffraction peak at 9. Xray powder diffraction patterns of pristine graphite, graphene oxide before and. Graphene oxide quantum dots derived from coal for bioimaging. Green preparation and characterization of graphene oxide. Having unique properties, graphene layers are a quite interesting nanomaterial for industrial applications.
Ftir spectra observed of zinc oxide nanoparticles in their investigation. The shoulder peak at 302 nm is started diminishing in less than 8 h of exposure to sunlight and completely vanished a er 16 h. The uv vis spectrum of polystyrene functionalized graphene in tetrahydrofuran shows a strong absorption peak around 275 nm, which is comparable to reduced graphene oxide after the conjugated graphitic structure has been restored by chemical reduction. Dispersions of fewlayer layers, multilayer 410 layers and thicklayer 10 layers graphene oxide go were prepared by a modified hummers method with different mass ratios of kmno 4 to graphite. But much higher amount of graphene oxide can leads to incomplete reduction and thus bad quality final product. Nanocomposites a lot of research works have been reported on graphene or rgo andor go. Though the extraction of graphene through hummers method is one of the oldest techniques yet it is one of the most suitable methods for the formation of bulk graphene. Graphene oxideiron iiivi oxides nanocomposites have been produced with a fast and onepot synthesis. Graphene oxide ngo was usually prepared by oxidation of gra phene.
Synthesis and characterization of graphene thin films by. Xray diffraction of graphene oxide and reduced graphene oxide synthesized by chemical reduction of exfoliated and intercalated graphite oxide is presented in figure 2. Surface functional groups of go layers and the oxidative debris od stacked on them were investigated after od was extracted. The spectra in figures 2a and 2b show two peaks corresponding to graphene oxide and graphene. The obtained graphene oxide was reduced to reduced graphene oxide by ascorbic acid. This article presents the influence of capping ligand and surface interaction types on the coarsening or reshaping behavior of surfaceimmobilized gold nanoparticles with different core size and shape.
Xray photoelectron spectra xps show that the change of uvvis absorption intensity of. Zno nanoparticles have been synthesized by precipitation method from zinc nitrate. Uvvis absorbance spectra of reduced graphene oxide rgo. The afm images of a graphene oxide and b reduced graphene oxide flake 9 figure 22. Graphene oxide was synthesized by a onestep environmentally friendly mechanochemistry process directly from graphite and characterized by raman, ftir and uvvis spectroscopies, atomic force. Synthesis, characterization, and spectroscopic properties. Advanced chemical reduction of reduced graphene oxide. Here, we report the efficient synthesis of ngo with.
Uvvis absorbance spectra of reduced graphene oxide rgo or graphene uvvis absorbance spectra of reduced graphene oxide rgo or graphene 200 250 300 350 400 450 500 550 5 4 3 2 1 intensity wavelength nm 270nm. The znonps were dispersed in ethanol with concentration of 0. Uvvis spectrum of graphene oxide raman spectrum of graphene oxide. Uvvis spectrum of iron oxide nanoparticles synthesized by two methods. Ftir spectra of iron oxide nanoparticles synthesized via thermal decomposition. The uvvis absorbance spectrum of zinc oxide nanopartic.
Xray photoelectron spectra xps show that the change of uvvis absorption intensity of go is caused by a conjugative effect related to chromophore aggregation. Graphene oxide quantum dot goqd and reduced good rgoqd were synthetized using a simple and straight methodology based on an oxidative treatment and sonication. Figure 2 shows the uvvis absorbance spectra of ansg and graphite oxide in water. What is your opinion about this uvvis absorption spectra. This work compares the properties of go and rgo with graphite. Xrd patterns showed that zno nanoparticles have hexagonal unit cell structure. The powder was characterized by xray diffraction, scanning electron microscopy, transmission electron microscopy, selectedarea electron diffraction, uvvis optical absorption, and photoluminescence spectroscopy analyses. Graphite oxide was synthesized from graphite power spectral pure, sinopharm chemical reagent co. Graphene and its oxides have attracted much attention because of their interesting electronic properties. Morphological transformation of gold nanoparticles on. Graphene can be obtained in the form of reduced graphite oxide. Electrochemically reduced graphene oxide sheets for use in. Research article preparation and characterization of.
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