44 results about "Cvd graphene" patented technology

A supported graphene device comprises at least one graphene feature of 1 to about 10 graphene layers having a predetermined shape and pattern, with at least a portion of each graphene feature being supported on a substrate. In some embodiments the device comprises graphene features supported on crystalline semiconductor substrate, such as silicon or germanium. The graphene features on a crystalline semiconductor substrate can be fabricated by forming an amorphous carbon doped semiconductor on the crystalline semiconductor substrate and then epitaxially crystallizing the amorphous semiconductor with carbon migration to the surface to form a graphene feature of one or more graphene layers. The epitaxy can be promoted by heating the device or by irradiation with a laser. Methods for fabricating graphene on a variety of substrates, over large areas with controlled thicknesses employ ion implantation or other doping techniques followed by pulsed laser annealing or other annealing techniques that result in solid phase regrowth are presented.

The invention provides a hydrothermal preparation method of a graphene-coated sulfur/porous carbon composite material and relates to a preparation method of the graphene-coated sulfur/porous carbon composite material for a positive electrode material of a lithium-sulfur storage battery. The hydrothermal preparation method is used for solving the technical problem that the electrochemical property of the positive electrode material of an existing lithium-sulfur battery, namely a graphene-coated sulfur-containing composite material, is low. The hydrothermal preparation method comprises the steps of mixing and scattering the sulfur/porous carbon composite material with graphene slurry or oxidized graphene slurry, carrying out hydrothermal synthesis to prepare a hydrogel column, and drying to obtain the graphene-coated sulfur/porous carbon composite material. According to the graphene-coated sulfur/porous carbon composite material prepared by utilizing the hydrothermal preparation method, the outer surfaces of the graphene sheet layers are coated with sulfur/porous carbon composite material particles, a graphene conduction network is generated among the particles, and the obtained graphene-coated sulfur/porous carbon composite material is in a hierarchical core-shell structure; the positive electrode material has the high specific capacity, the long cycle life and the good rate capability; the composite positive electrode material can be used as a positive electrode material in a lithium secondary battery.

A flexible electrode comprises an activated cotton textile composite comprising activated carbon fibers, nickel sulfide nanoparticles and graphene and a process for making the flexible electrode. The process may comprise preparing a cotton textile containing Ni(NO₃)₂. Then, the cotton textile containing Ni(NO₃)₂ may be heated at a first temperature to produce an activated cotton textile composite comprising activated carbon fibers, nickel nanoparticles and graphene. The activated cotton textile composite may be then treated with sulfur to produce an activated cotton textile composite comprising activated carbon fibers, nickel sulfide nanoparticles and graphene. The nickel sulfide particles may be NiS₂ nanoparticles in a form of nanobowls, and distributed on a surface and inside the activated carbon fibers. The activated carbon fibers and the nickel sulfide nanoparticles may be coated with graphene. Banana peels may be activated and treated with the similar processes to form electrodes for both supercapacitor and battery applications.

The invention belongs to the field of inorganic/polymer optic nano composites and particularly relates to a transparent high-refractivity graphene quantum-dot/polymer nano composite film and a preparation method thereof. The composite film is formed by graphene quantum-dot and polymer through ultraviolet curing and thermocuring. Before curing, in each 1mL of polymer monomer, the content of graphene quantum-dot is 0.1-1g. The graphene quantum dots (GQDs) is used as inorganic nano phase, the polymer monomer is used as solvent, the GQDs is synthetized in the polymer monomer by the solvothermal method and then are directly cured to be film by filtering, spraying coating, adding trigger, and double treatment of ultraviolet curing and thermocuring. The transmissivity of the transparent high-refractivity graphene quantum-dot/polymer nano composite film prepared by the film materials ranges from 80% to 95%, refractivity ranges from 1.5 to 2.8, and the transparent high-refractivity graphene quantum-dot/polymer nano composite film can be applied to antireflection coating, optical waveguide materials, optical lenses and other photoelectric fields.

The invention relates to a method for preparing graphene load nano silver-nickel alloy composite powder materials. The method aims to solve the problems that graphene load nano silver-nickel alloy composite materials prepared in the prior art are nonuniform in scattering and poor in chemical stability. The method comprises the first step of intercalation and expansion, the second step of stripping and the third step of the preparation of the graphene load nano silver-nickel alloy composite powder materials. Oxidized graphene is prepared through an oxidation-reduction method, then the oxidized graphene, silver ions and nickel ions are mixed and restored through reducing agents to obtain the graphene nano silver-nickel alloy composite materials, the method is simple and fast, any surface dressing agent does not need to be added, and alloy particles on the surface of the graphene are uniform in distribution and stable in chemical performance. The method is used for preparing the graphene load nano silver-nickel alloy composite powder materials.

The invention relates to the technical field of photocatalysis, and specifically relates to a graphene-based gamma-FeO2O3 composite material photocatalyst, and a preparation method and use thereof. According to the graphene-based gamma-FeO2O3 composite material photocatalyst, gamma-Fe2O3 particles are attached to the surface of graphene, size distribution of the graphene is 1-50 mu m and the size distribution of the gamma-Fe2O3 particles is 20-500nm. The preparation method mainly comprises the following steps: preparation of graphite oxide; preparation of a graphite oxide iron sulfate hydrate intercalating matter; and preparation of the graphene-based gamma-FeO2O3 composite material photocatalyst. The graphene-based gamma-FeO2O3 composite material photocatalyst prepared by the preparation method disclosed by the invention has high carrier transmission rate, large specific surface area and low energy gap, so that the photocatalyst has extremely high activity of photocatalytic degradation of organic matters. The photocatalytic activity of the photocatalyst disclosed by the invention is over 86% higher than that of pure gamma-FeO2O3 particles. The photocatalyst has good circular stability, can be repeatedly used for many times, and does not cause secondary pollution in the photocatalytic degradation process.

The invention relates to a method for preparing a ferric vanadate-graphene negative electrode composite material. The method comprises the following steps: dispersing sheet layers of graphene, forming ferric vanadate on the surface of graphene, growing and performing after-treatment on the ferric vanadate attached to the surface of graphene. According to the method disclosed by the invention, the sheet layers of graphene are dispersed, so that the ferric vanadate is uniformly attached to the surface of the graphene. Therefore, the ferric vanadate-graphene negative electrode composite material is uniform in texture and high in dispersity, the performance is greatly improved, and hydrogen peroxide is added into graphene turbid liquid, so that reaction is carried out on the surface of the uniformly dispersed graphene, functional groups are generated, a negative ion state is formed, ferrous iron ions are easily adsorbed, the reaction rate is accelerated, the adsorption rate is increased, and the ions react with vanadate on the graphene surface so as to form uniform particles. The ferric vanadate-graphene negative electrode composite material disclosed by the invention has low discharge voltage and extremely high discharge capacity, the raw materials are wide in source, and the cost is reduced.

The invention discloses a laser-assisted graphene tooth 3D printing process. The technique is combined with the graphene and the laser heat treatment technique, a high-quality graphene tooth is obtained through 3D printing, the graphene is added into a tooth base material, the property of the base material is not changed, the coefficient of thermal expansion of the tooth is reduced, the overall mechanical property is improved, and the ultra-intense laser is radiated on the tooth material in the laser heat treatment technique to improve the wear resistance, the metal-ceramic binding tightness and the material density of the tooth material. Based on the laser, the characteristics of instantaneous high temperature, controllable irradiation and short quenching time are provided, the printed graphene tooth not only is accurately fitted with the alveolar ridge of a patient, but also is high in stability, wear resistance and mechanical strength, a plurality of tests like the metal-ceramic binding strength test, the thermal expansion coefficient experiment and the surface roughness test indicate that the graphene tooth prepared through the technique has better properties than the traditional material, and has an industrialized development future.

The invention relates to a manufacturing process of a graphene transparent conductive film. The manufacturing method includes the steps of 1), uncoiling a copper foil in a vacuum chamber, heating a copper-clad chemical deposition reaction zone by using a resistor, feeding in methane gas and hydrogen, subjecting a copper-clad surface to chemical sedimentation to generate a graphene layer, and then adopting plasma to perform etching processing on the graphene layer; 2), adopting a gravure printing process to obtain an oxidize graphene layer; 3), obtaining an oxide graphene film; 4), coating a copper chloride etching solution which is 200g/L in concentration on a copper-clad face of the oxidize graphene film; 5), subjecting the oxidize graphene film to thermal annealing and reduction; 6), coating resin adhesive, sticking the film for packaging, and finally obtaining the patterned graphene transparent conductive film. The manufacturing process is short in film forming time, and low-cost and large-scale mass manufacturing can be realized; the graphene transparent conduction film is high in electric conductivity, good in flexibility, high in pattern definition, higher in acid and alkali resistance of the transparent conductive film and lower in cost.

The invention discloses a preparation method of a graphene nano-hole which is supported by a micropore, belonging to the fields of application of heavy ion beams and processing of films. A porous graphene composite material supported by the micropore is mainly characterized by comprising monolayer graphene, wherein the monolayer graphene is arranged on a polymer film; a nanoscale hole is formed in the graphene, overlapped and communicated with a cone-shaped hole of the polymer film. Through the preparation method, a graphene/polymer film composite structure is irradiated by using high-energy heavy ions; a hole with the diameter being several nanometers is formed in the graphene by using irradiation damage effect of the heavy ions; meanwhile, a columnar damage area is formed in the polymer film; then an irradiated area of a polymer is etched to form a cone-shaped nano-hole by using a chemical etching method; since the position of the graphene hole is overlapped and communicated with the position of the cone-shaped hole of the polymer, the graphene nano-hole which is supported by the micropore can be obtained. Due to the support effect of the polymer micropore, the graphene nano-hole is wide in application prospet in rectification of the ions, filtration and screening of the ions and detection of biological molecules.

The invention provides graphene-based hierarchical pore capacitor carbon and a preparation method thereof. The preparation method comprises the following steps: water-soluble sugar and a graphenes substance are subjected to a hydro-thermal reaction, a cross-linking agent is added during a reaction process, an activator is added after the reaction is complete, and then the materials are subjected to a carbonization reaction to obtain the product. The cross-linking agent is a nitrogenous foaming agent, and the activator is selected from one or more of potassium hydroxide, sodium hydroxide, zinc chloride and phosphoric acid. According to the invention, stacking and agglomeration of the graphene can be inhibited with a larger degree, the specific surface area and amount of porosity are increased, and the specific surface area utilization rate and specific capacitance are increased.

The invention discloses a high-specific-energy flexible integrated electrode and a preparation method therefor. The electrode is prepared from the following components based on mass percentage: 20-80% of graphene, 0-10% of conductive carbon black, and 10-80% of sulfur-containing material, wherein the content of the conductive carbon black is not zero; the graphene and the conductive carbon black form a flexible graphene/conductive carbon black self-supporting thin film; and the sulfur-containing material is elementary sulfur or -S<m->-structured polysulfide, wherein m is greater than 2. By virtue of the high-specific-energy flexible integrated electrode prepared by the invention, the utilization rate of sulfur in the electrode is improved; in addition, the high-specific-energy flexible integrated electrode is high in conductivity and mechanical performance, capable of effectively relieving volume expansion of an active material in the charge-discharge process, and capable of improving the cycle performance and high specific energy characteristic of a battery.

The invention relates to the technical field of inorganic materials, and discloses a preparation method for a ferrous carbonate/graphene composite material. The preparation method comprises the steps of: I. mixing graphene materials, water-soluble ferrite, urea and water to form a suspension, wherein the mass ratio of the graphene materials to the water-soluble ferrite is (0.02-0.2):1, and the amount-of-substance concentration ratio of the urea to the water-soluble ferrite is (20-100):1; II. putting the suspension into a reaction kettle, controlling the temperature to be 100-180DEG C, and carrying out hydrothermal reaction for 4-12h to obtain the ferrous carbonate/graphene composite material. The invention further provides a lithium ion battery prepared by taking the ferrous carbonate/graphene composite material as a negative electrode material. By being synthesized through low-temperature hydrothermal reaction, the ferrous carbonate/graphene composite material is high in specific capacity and good in cycling performance, and has excellent development prospects after being applied to the negative electrode materials of the lithium ion battery.

The invention relates to a method for preparing a lithium ion battery material. The method comprises the following steps: firstly, mixing high-purity graphene powder, anionic surfactant, antifoaming agent, dispersing agent and solvent to obtain a viscous graphene slurry; adding a certain amount of polyacrylonitrile (PAN) or polyaniline powder to the graphene slurry, performing ball milling to uniformly mix the raw materials to obtain a composite slurry; drying and carbonizing the composite slurry to obtain graphene porous material powder. The graphene porous material powder and the aqueous solution of SnCl 4 are used as raw materials to synthesize a tin dioxide/graphene porous composite material through a hydrothermal method. The tin dioxide/graphene powder prepared by the invention has aporous structure, has the advantages of high specific surface area, high electrical conductivity, high mechanical strength, and the like, and can effectively buffer volume change and internal stress of tin dioxide during charging and discharging and improve the capacity and cycle performance of the electrode.

The invention discloses a preparation method of a graphene aerogel epoxy resin composite fracturing proppant. The preparation method comprises the following steps: 1, dropping a certain concentrationof graphene oxide suspension in a frozen mixture of petroleum ether and methyl silicone oil to form graphene oxide droplets; 2, moving the graphene oxide droplets in a freeze dryer for freeze drying to obtain graphene oxide aerogel pellets; 3, performing high-temperature thermal reduction on the graphene oxide aerogel pellets into graphene aerogel pellets; 4, introducing the graphene aerogel pellets into an epoxy resin and curing agent mixture for vacuum compounding and then heating and curing to form the grapheme epoxy resin composite fracturing proppant; the pellet type fracturing proppant made by graphene aerogel and epoxy resin compounding has the advantages of low density and high compression strength and can significantly improve the fracturing and yield-increasing efficiencies.

The invention discloses a graphene coated carbon-sulfur composite positive electrode, a preparation method thereof and a secondary aluminum battery. The graphene coated carbon-sulfur composite positive electrode is prepared by compounding a carbon nanotube sponge with elemental sulfur and then dipping the composite material in graphene slurry. The carbon nanotube sponge has a three-dimensional network structure and is capable of adsorbing active substances and lowering dissolution of sulfide by virtue of large specific surface area. A conductive network, formed among particles after the surface of the composite material is coated with graphene, is capable of lowering contact resistance generated by carbon nanotube sponge-sulfur surface insulativity, inhibiting the dissolution of a surface active substance, namely sulfur, of the carbon nanotube sponge, and improving the cycling performance of the composite positive electrode. The positive electrode prepared by the method is free of a conducting agent or a binding agent and is environmentally friendly and cheap. The secondary aluminum battery prepared by applying the composite positive electrode is excellent in cycling performance and has environment-friendly and safe effects.

The invention discloses a g-C3N4 crystal phase/amorphous phase homojunction as well as a preparation method and application thereof. The homojunction is characterized in that crystal phases and non-crystal phases are alternately distributed on the same graphite phase C3N4 to form the homojunction. The preparation method comprises the following steps of performing primary heat polycondensation on nitrogen-containing organic precursors; grinding the obtained blocky graphite phase carbon nitride into powder; performing ultrasonic thinning and dispersion to obtain powder; performing secondary heatpolycondensation on the powder to obtain a product. The homojunction and the preparation method have the advantages that simplicity is realized; the implementation is easy; the cost is low; the repeated performance is good; the enlightening significance is realized on the synthesis of layered graphene semiconductor materials. The crystal phase and amorphous phase part of the obtained homojunctionis adjustable in proportion. Compared with the homojunction with the conventional appearance, the homojunction has higher catalysis activity, is favorable for the efficient separation of electron-hollow hole pairs, and improves the reaction activity. Compared with the homojunction prepared by a seed growth method, the homojunction has the advantages that the synthesis process is simple. In an aspect of visible light photocatalytic degradation, the relatively excellent photocatalytic performance is far higher than that of ordinary flaky carbon nitride.

The invention discloses a method for preparing a graphene chemically modified electrode through in-situ growth, which mainly comprises the following steps: (A) substrate cleaning; (B) in-situ growth of graphene: placing the substrate obtained by the step (A) in a clean quartz boat, and placing the quartz boat in a quartz tube of a horizontal resistance furnace; introducing argon to remove oxygen in the quartz tube; under the protection of the argon, heating the quartz tube to the growth temperature of graphene; preserving heat for 1-180 minutes while introducing carbon source gas and hydrogen instead; then, cooling to room temperature under the protection of argon, and taking out a product to obtain a substrate with in-situ grown graphene; (C) connecting the substrate with graphene of in-situ growth, obtained by the step (B), with a wire or directly putting the substrate into a clamp to obtain the graphene chemically modified electrode. The preparation process of the method is simple, the preparation efficiency is high, and the method is suitable for large-scale production; the prepared graphene chemically modified electrode has good quality and excellent detection performance.

The invention discloses a preparation method of graphene quantum dots. The method comprises the following steps: a. adding pyrene into concentrated nitric acid, carrying out a condensation reflux reaction at 80 DEG C for 24-48 h, adding excess deionized water after the reaction is completed and performing suction filtration by using a filter membrane, performing repeated suction filtration and washing until the pH of a solution is neutral, and then placing the reaction product in a vacuum oven for oven-drying at 65 DEG C-85 DEG C to obtain trinitropyrene; b. weighing trinitropyrene and sodiumsulfite and performing dissolving in ethanol and performing uniform stirring, transferring the solution into a reaction kettle with a polytetrafluoroethylene substrate, and carrying out a reaction ata high temperature of 180 DEG C-210 DEG C for 10 h-12 h; and c. filtering the reaction product through a 0.22 [mu]m filter membrane to remove unreacted particles after the high temperature reaction iscompleted, then performing purification by a column chromatography separation method, and performing drying to obtain a yellow-brown solid powder, namely the graphene quantum dots. The hydrophobic graphene quantum dots prepared by the method can detect water content in organic solvents according to changes of fluorescence, and carry out cell imaging.

The invention discloses a method for detecting trace hydroquinone by using a graphene/carbon nano tube modified electrode. The graphene/carbon nano tube modified electrode is a working electrode, and a method for detecting trace hydroquinone in water is established by means of different current catalytic strengths of the graphene/carbon nano tube modified electrode to hydroquinone with the concentration of respectively 0.6mu mol/L, 0.8mu mol/L, 2mu mol/L, 4mu mol/L, 6mu mol/L, 8mu mol/L, 20mu mol/L, 40mu mol/L and 60mu mol/L. The scanning potential is -0.2-0.6V, and the scanning speed is 100mV/s. In a 0.02mol/L phosphate buffered solution (PBS) with a pH value of 7.4, the concentration of the hydroquinone is within the range of 6*10<-7>-6*10<-5>mol/L, a favorable linear relation is formed between the concentration and the catalytic current strength on the surface of the electrode, and the detection limit is 2.13*10<-7>mol/L. The method is sensitive, good in selectivity, and more convenient and simpler in detection of low-concentration hydroquinone.

The invention relates to the technical field of environment protection, and particularly discloses an application method of a graphene and CuMn2O4 composite material in catalytic ozonation pollutant-removal water treatment. According to the graphene and CuMn2O4 composite material, graphene is added and accordingly improves the specific surface area of the composite material, and transfer of electrons on the surface of a catalyst is promoted; by adding CuMn2O4, the structure of the composite material is more stable, the cost of the catalyst is reduced, and secondary pollution is not easily caused. The synthesized graphene and CuMn2O4 composite material has higher ozone catalyzing capability in a catalytic ozonation system and can more efficiently decompose organic matter which is difficultto decompose; meanwhile, by accelerating conversion of ozone molecules, generation of bromate as a carcinogenic side product can be inhibited more effectively. By adopting the graphene and CuMn2O4 composite material, the removal rate of the organic matter which is difficult to decompose reaches 90% or above, and therefore the graphene and CuMn2O4 composite material has wide application prospects in the field of advanced drinking water treatment or urban domestic wastewater regeneration treatment.

The invention belongs to the technical field of electrochemical materials, and particularly relates to a preparation method of an electromagnetic shielding heat dissipation film. The method comprisesthe following steps of obtaining carbon nanotube films and graphene films; after at least one layer of the carbon nanotube films and at least one layer of the graphene films are alternately laminated,performing hot pressing treatment in a protective gas atmosphere of 2,800-3,000 DEG C for 8-10 hours to obtain a laminated function layer of carbon nanotubes and graphene; obtaining a base layer, andattaching the laminated function layer to one side surface of the base layer by using an adhesive; and obtaining a heat conduction adhesive, and applying the heat conduction adhesive to the other side surface, away from the base layer, of the laminated function layer to form a heat conduction adhesive layer, and obtaining the electromagnetic shielding heat dissipation film. The preparation methodof the electromagnetic shielding heat dissipation film is simple in process, easy to operate and convenient for industrial production and application.

The invention relates to the technical field of lithium ion anode materials, and discloses a vanadium pentoxide/graphene-hollow carbon sphere nano composite material and a preparation method thereof.The preparation method of the vanadium pentoxide/graphene-hollow carbon sphere nano composite material comprises the following steps: S1, preparing vanadium pentoxide/graphene; S2, preparing hollow carbon spheres; and S3, preparing the vanadium pentoxide/graphene-hollow carbon sphere nano composite material. The technical problem solved by the invention aims at the defects of the prior art, hollowcarbon spheres are introduced into a vanadium pentoxide/graphene composite material, the electronic conductivity of the hollow carbon spheres is not as good as that of graphene, and pore structures of graphene are not as rich as that of the hollow carbon spheres, so that the combination of the two generates a synergistic effect to greatly improve the electrical performance of the vanadium pentoxide/graphene anode material.

The invention discloses an Ni film annealing patterned graphene preparation method based on 3C-SiC/chlorine gas reaction, which mainly solves the problem that the graphene prepared by the prior art can cause damage and result in electron mobility reduction when being used for photoetching technology as a transistor channeling material. The preparation method comprises the following steps: (1) growing a carbonization layer on an Si substrate as a transition layer; (2) growing a 3C-SiC film on the carbonization layer; (3) depositing SiO2 on the surface of the 3C-SiC film, and etching a pattern on the SiO2; (4) reacting the patterned sample wafer with Cl2 to generate a carbon film; (5) removing the SiO2 except the pattern; (6) depositing an Ni film on the carbon film by using an electron beam; and (7) putting the sample wafer with the deposited Ni film in Ar gas, and annealing for 15-30 minutes so that the carbon film reconstitutes the patterned graphene in the pattern position. The invention has the advantages of simple technique and high safety; the graphene can be directly used as a conducting channel without photoetching when making a transistor on the graphene; and the graphene can be used for making graphene transistors with superhigh mobility.

The present invention relates to a method for preparing a graphene-containing inorganic coating composition for coating non-ferrous metal objects and a graphene-containing inorganic coating composition prepared thereby, in which the inorganic coating composition contains liquid silica sol that emits far-infrared rays and powdery graphene that has very excellent thermal conductivity, and thus it emits far-infrared rays beneficial to the human body while having excellent durability and thermal conductivity. The method comprises: adding isopropyl alcohol as a solvent to liquid silica sol and a liquid sealant, followed by uniform stirring for 2-3 hours, thereby preparing a first liquid binder; adding powdery graphene, filler and pigment to the first liquid binder, followed by stirring for 8-10 hours, thereby preparing a second binder; and adding a predetermined amount of an adhesion-enhancing agent to the second binder, followed by aging at a temperature of 25 to 32° C. for 9 to 11 hours.