How is thin paper oxide graphite and graphene preparation and characterization

രചയിതാവ്: ഐഫ്ലോപവർ – പോർട്ടബിൾ പവർ സ്റ്റേഷൻ വിതരണക്കാരൻ

The thin paper-like oxidized graphite layer was successfully prepared by modified Hummers method, and the prepared sheet-like oxidation graphite layer was reduced as a graphene nanomaterial with a hydrazine. Synthesis products by Fourier transform infrared spectroscopy (FT-IR), Raman Spectroscopy (RS), X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmitting Electroractor (TEM), and Agency (AFM), etc. The structure and performance are characterized.

The results show that the thickness of graphene is 0.36 nm, the number of layers is 3. In addition, the reaction mechanism of the modified Hummers method was prepared by the reaction mechanism of thin paper-like oxidation graphite, and the chemical reaction process occurring during the oxidation of the graphite oxidation was analyzed.

In 2004, GEIM et al, prepared a new two-dimensional atomic crystal-graphene composed of SP2 hybridized carbon atomic layers using mechanical stripping method. The basic structural unit of graphene is a benzene six yuan ring, which is only 0.34 nm.

Therefore, graphene has many excellent physical chemistry properties, such as 100 times the strength of steel, up to 130gPa, carrier mobility reaches 15000 cm2 / (v · s), the thermal conductivity is 5000W / (m · K ). In addition, graphene also has special properties such as room temperature quantum Hall effect and room temperature ferromagnetic properties. At present, the preparation method of graphene is mainly micro-mechanical stripping method, chemical vapor deposition, chemical redox reduction method, crystal epitaxial growth method and solvent heat method.

Among them, the micromechanical stripping method can prepare graphene of micron size, but the controllability is low, it is difficult to achieve large-scale production. The crystal epitaxial growth method is prone to reconstruction due to the surface of the SiC crystal, so that a large area, a thickness is equal to one graphene. The chemical vapor deposition method (CVD) is substrate with a metal single crystal or a metal film, which can grow a thin layer graphene sheet layer, but the graphene purity is not high, and large-scale production cannot be achieved.

The solvent heat method is due to harsh conditions such as high temperature and high pressure, and the product conductivity is low, and there is no possibility of mass production. The chemical redox reduction method is to prepare graphene by ultrasonic stripping and reduction process by Hummers method. Due to the short production cycle of the method, the advantages of high synthetic production are widely affected and studies.

During the Hummers method, the graphite is prepared, including low temperature (0 ° C), medium temperature (38 ° C) and high temperature (98 ° C), and the oxidizing agent is concentrated H2SO4 and KMNO4. Through the study of the graphite oxidation process, the Hummers method is modified, that is, the time period in which the medium temperature reaction stage is extended, and the high temperature reaction stage is canceled. Canceling the reaction process of the high temperature stage, not only avoiding the eruptism hazards caused by sulfuric acid during high temperature reactions, but also avoiding thermal decomposition reaction in the high temperature stage, reducing the degree of oxidation of graphite.

In the theory and experiment, the layered oxide layer can be prepared under low temperature and safe and stable conditions. The preparative graphite was reduced by hydrate hydrate to prepare graphene nanomaterials, and the preparative thin paper-like oxide graphite and graphene material were produced. 1, experiment 1.

1, raw material scale graphite (granularity: 325 mesh, first-rich nanotechnology Co., Ltd.); concentrated sulfuric acid (95% ~ 98%); potassium permanganate, sodium nitrate, hydrogenated (30%), hydrochloric acid, chlorination Barium, hydrate (80%), etc.

are analyzed. The above drugs are not specially mentioned, and they are purchased from the Shanghai Chemical Reagent Company of China Pharmaceutical Group. All the above reagents are not handled directly.

1.2, sample preparation 1) Thin paper-like oxide ink (GO) layer preparation of 230 mL (98%) concentrated sulfuric acid in 1000 ml of three flasks, under constant temperature magnetic force and ice water bath, 5.0 gnano3 and 10.

0 g Mixtures of graphite, stirring medium at medium speed for 30 min, so that it is mixed. 30GKMNO4 gradually added to the mixture, and stirring at 0 ° C for 2 h. The three flasks were moved into a constant temperature water bath that had been adjusted to a temperature of around 38 ° C, continued for 30 h, and the medium temperature reaction was carried out.

After the temperature of the medium temperature reaction, the mixture was transferred into a 2000 ml beaker, diluted with deionized water to 1000 mL, and 200 mL (5%) H2O2 was added, and the reaction liquid turned into a golden color. The centrifugation was carried out with a high-speed centrifuge, and the rotational speed was 4000 r / min, washed with a pre-pre-pre-preformed 5% HCl and deionized water until the sulfuric acid sulfuric acid in the filtrate was detected, and the suspension was displaced in the evaporating dish, 60 Vacuum drying in vacuo, forming oxidized graphite. 2) The reduction of graphene was dispersed in a 100 ml of the resulting graphite ink in a 100 ml of aqueous solution to obtain a brown-yellow suspension, and the ultrasound conditions were dispersed under a three-mouth flask, heated to 90 ° C, drip 2 ml of hydrated hydrate, here The reaction was filtered after 24 h under conditions, and the resulting product was washed multiple times with methanol and water, and the graphene was dried over 60 ° C.

1.3, test and characterization XRD diffraction analysis using Japanese Rigaku D / MAX-RB diffractometer (Cu target, Kα radiation, λ = 0.154056 nm), scanning range 5 ° ~ 80 °; infrared spectroscopy (FT-IR) analysis ThermonicoLET's NEXUS Fourier transform infrared spectrum, KBR tablets, wavelength range 400 ~ 4000cm-1; Raman spectroscopy (Raman) analyzes the INVIA-type microclassless laser Raman spectrometer of British Renishaw, The record range is from 100 to 3200 cm-1, the laser wavelength is 785 nm, the spatial resolution is 1 μm lateral direction, longitudinal to 1 μm; scanning electron microscope (SEM) adopts a S-4800 FESEM scanning electron microscope; transmissive electron microscope (TEM) adopts Japan JEO company JEM-2100F-type field transmit high-resolution transmission electron microscope; atomic force scanning probe microscope (AFM) adopts US Veeco's Nanoscope4-type atomic force microscope.

Conclusion a. By analyzing the oxidation process of the graphite oxidation process, the modified Hummers method in which the high temperature reaction stage was canceled, and the graphene was obtained by ultrasound peeling and hydrated hydrate reduction treatment. B.

TEM and AFM test results show that the thickness of graphene is 0.36 nm, the number of layers is 3. സി.

The method is safe and simple, the output is large, easy to control, provides a rapid and simple, large-scale preparation of thin paper-shaped graphene, provides a foundation for the commercial application of graphene. .