21results about "Single layer graphene" patented technology

The invention discloses a method for preparing few-layer graphene through supercritical CO2 stripping, and belongs to the technical field of graphene preparation. The preparation method comprises the following steps: mechanically crushing natural crystalline flake graphite, and carrying out airflow classification purification to obtain graphite powder with the particle size of 50-100 mu m; the method comprises the following steps: mixing graphite powder and a bio-based anionic surfactant, adding the mixture into a supercritical reaction kettle, and introducing CO2 to replace air; carrying out constant-temperature and constant-pressure pretreatment under the conditions that the temperature of the reaction kettle is 40-60 DEG C and the pressure is 2-4MPa, increasing the pressure to 15-20MPa, and carrying out stirring reaction for 2-3h; and after the reaction is finished, slowly releasing the pressure to normal pressure, carrying out centrifugal classification on the product, washing to be neutral, and carrying out vacuum freeze drying to obtain the few-layer graphene. The problems that an existing supercritical CO2 stripping process is poor in environmental protection property, products are prone to agglomeration and low in efficiency are effectively solved, the number of layers of the products is 1-5, the proportion of 1-3 layers is larger than or equal to 75%, the sheet diameter is 0.8-2.0 micrometers, and the method has the advantages of being high in crystallinity and low in defect density; in addition, according to the method, the CO2 recycling rate is larger than or equal to 95%, the stripping efficiency reaches 85% or above, cost is low, and the method is suitable for large-scale industrial production.

The invention discloses an optimization method of a graphene nanobelt edge structure, and belongs to the technical field of material preparation. Joule heat generated by bias voltage is used for driving edge atom migration and interlayer sublimation, in single-layer GNR treatment, edge recrystallization is achieved through constant bias voltage, the edge structure is improved, and a foundation is laid for subsequent conductivity optimization and width reduction; the step bias strategy further regulates the width and the conductivity in a coordinated mode, the performance is gradually improved by accurately controlling the change and the holding time of the bias, and a new thought is provided for preparation of high-performance nano electronic devices.

The invention provides an industrial-scale graphene film ultrafast reel-to-reel deposition method which comprises the following steps: vacuumizing the inside of CVD (Chemical Vapor Deposition) equipment to be in a vacuum state, filling pretreatment gas, and pretreating a copper foil serving as an initial substrate; filling mixed gas of methane and inert gas into the CVD equipment, and changing the vacuum state in a cavity of the CVD equipment into a low-pressure state of 1-100 Torr; after the temperature in the CVD equipment chamber is increased to the preset temperature, the copper foil is rotated in a roll-to-roll mode at the transmission speed of 300-2000 mm / min, chemical vapor deposition is conducted on the copper foil in the CVD equipment chamber, and the graphene film is prepared on the surface of the copper foil. Compared with the prior art, the preparation rate of the graphene film can be increased by about 7 times, the length of the prepared single-layer graphene film can reach 1000 m or above, and the method is suitable for industrial-scale mass production preparation of the high-quality single-layer graphene film.

This invention discloses a graphene preparation apparatus and method using a high-voltage pulse power supply. The preparation apparatus includes a sliding track, a fixed outer shell and a movable outer shell disposed on the sliding track, and a four-way tube disposed between the fixed and movable outer shells. The four-way tube is fixedly disposed on the sliding track, with its upper port connected to a nitrogen source, its left port connected to a conductor, and its right port connected to another conductor. The two conductors are respectively connected to a test current source, and the positive terminal of the high-voltage pulse power supply is applied to the same side of the conductors and the positive terminal of the test current source. This invention has the advantages of stable and rapid preparation, high-quality graphene, and simple operation, and can effectively solve the problems of long preparation time and unstable graphene quality in traditional methods. At the same time, it saves energy and raw materials, improves preparation efficiency and performance indicators, and has high practical value.

The application relates to a method for preparing fluorinated graphene, and belongs to the graphene material field. The preparation method comprises the following steps: mixing and dispersing waste lithium battery recovery graphite powder, an intercalation agent and a dispersing agent in water to form a slurry, keeping the slurry at 40-60 DEG C for 4-8 hours, then spraying the slurry through a high-pressure device to form high-speed jets, and realizing graphite layer peeling through the cross impact of multiple jet beams, then adding a fluorination agent, keeping the slurry at 150-200 DEG C for 6-12 hours, centrifugally separating upper clear liquid, filtering and washing, vacuum drying, and obtaining fluorinated graphene. The application realizes graphite layer peeling through liquid cross impact, has high production efficiency, the obtained graphene sheet layer is regular and neat, has few structural defects, and the performance of the graphene is improved; the peeling strength can be adjusted by adjusting the jet speed, different layer number graphene products can be obtained, and the production is continuous, and the efficiency is relatively high; the raw material is waste lithium battery recovery graphite, the cost is low, the obtained graphene contains oxygen-containing functional groups, and has good water solubility.

The application discloses a graphene preparation method based on interlayer stress resonance. Macroscopic mechanical rotation energy is converted into high-frequency and directional stress energy which can precisely act on the van der Waals force between graphite layers through a series of carefully designed physical processes. Under specific rotation conditions, unstable vortex structures (such as Taylor vortex flow) are generated in the confined fluid. When the stress wave formed by the vortex in the viscoelastic fluid is coupled with the intrinsic vibration frequency between the graphite layers, resonance phenomenon is triggered. The resonance can amplify the strain energy between the graphite layers, so that the interlayer van der Waals force is efficiently and selectively overcome under the condition of energy input far lower than the in-plane fracture threshold of carbon-carbon bond, and the graphene is exfoliated to obtain large and few-layer graphene.

The application discloses a method for preparing single-layer graphene by catalytic reduction of CO2, which comprises the following steps: introducing CO2 gas into a fluidized bed reactor through a raw gas inlet, preparing CO and CO2 containing gas under the action of a reducing agent in an oxygen-free environment at 1000-1300 DEG C, introducing the CO and CO2 containing gas and a mixture containing nano catalyst into a two-stage Venturi jet unit from a product outlet and a mixed gas tank respectively, fully mixing and uniformly distributing the mixture, and preparing single-layer graphene under the action of the nano catalyst in an electric arc discharge reaction unit; the greenhouse effect gas CO2 is selected as a carbon source, and a thermal chemical series connection plasma is used to help the graphene nucleation of the CO / CO2 mixture and maintain a high growth rate of product seeds, so that large-scale single crystals are obtained; the reaction condition is controllable, and the method can be continuously produced, thereby providing a process basis for solving the current CO2 emission and energy shortage problems.

The application belongs to the field of optical functional nanomaterials, and particularly relates to an adjustable light-absorbing sheet based on an upright micro-nano graphene sheet and a preparation method thereof. The method is to change the micro-morphology and size of the upright micro-nano graphene sheet by adjusting the growth parameters of a radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) device, such as temperature, time, gas flow and radio frequency power, so as to realize the regulation and control of the light-absorbing performance of the light-absorbing sheet. The adjustable light-absorbing sheet has the characteristics of simple preparation process, low cost and low-temperature preparation, and does not need a catalyst. The light-absorbing rate of the adjustable light-absorbing sheet is as high as more than 99%, and the structure of the double-layer transparent substrate sandwiching the upright graphene film also protects the graphene, so that the graphene has the characteristics of scratch resistance and repeated use.

Amorphous two-dimensional graphene-like carbon films provide benefits to a variety of applications due to advantageous electrical, mechanical, and chemical properties. Methods are provided to efficiently and cheaply create high-quality amorphous two-dimensional carbon films with embedded graphene-like nanocrystallites using coal as a precursor. These methods employ solution-phase deposition of coal-derived graphene-containing quantum dots followed by relatively low-temperature annealing / crosslinking of the quantum dots to form a single two-dimensional layer of carbon that includes a plurality of randomly-oriented discrete graphene domains connected to each other via amorphous carbon regions. Multi-layer films can be easily created by repeating the deposition and annealing processes. Two-dimensional carbon films formed in this manner exhibit improved properties when compared to crystalline graphene sheets and have properties especially suited to use as the storage medium of memristors. Further processing can result in large free-standing two-dimensional graphene-like carbon thin films that can be used as membranes or for other applications.

Disclosed are a single-layer edge-oxidized graphene and a preparation method therefor, which belong to the technical field of graphene materials. A single-layer graphene is used as a raw material and electrolyzed by applying an ultra-low-frequency alternating current with a low current density to prepare the single-layer edge-oxidized graphene. The number of oxygen free radicals generated from an electrolyte is regulated and controlled by adjusting the current intensity and frequency of the applied alternating current, a small number of oxygen free radicals are reacted at the sites having more active binding energy of the edge of the single-layer graphene, and the low current intensity and the short current time result in insufficient invasion of generated oxygen radicals into the plane of the single-layer graphene, thereby constructing the single-layer edge-oxidized graphene. The polarity of the prepared single-layer edge-oxidized graphene is increased on the basis of retaining the excellent physical and chemical properties of graphene, thereby greatly improving the dispersing capability of the graphene in polar solvents.

The present invention pertains to a process for direct deposition of graphene oxide onto a substrate of interest from a gaseous source of at least one carbon precursor, using a plasma-enhanced chemical vapor deposition method. It is also directed to a device for implementing this process.

The application relates to a graphene transfer method, which comprises the following steps: graphene growth, stress layer deposition, temporary bonding glue film forming, substrate attaching, peeling, van der waals bonding with a target substrate, debonding, cleaning and stress layer etching. The graphene obtained by the method is undoped, free of metal trace residues, free of damage and wrinkles, and atomically flat, and can be used for large-scale production and semiconductor-compatible graphene, thus having a good market application prospect.

A process for preparing a graphene quantum material includes: providing a carbon-containing precursor; decomposing the carbon-containing precursor with ultra-fast laser to obtain the graphene quantum material; optionally reducing graphene oxide into graphene with laser; and optionally subjecting the graphene quantum material to microwave heating.

The application belongs to the field of functional films, and particularly relates to a preparation method of high-quality graphene heat-conducting and electricity-conducting film. The preparation method uses weakly oxidized graphene or graphene doped with heteroatoms in a covalent lattice as raw material, obtains a layered film through liquid-phase assembly, and obtains the high-quality graphene heat-conducting and electricity-conducting film through high-temperature graphitization heat treatment. The vacancies and defects generated by the covalent doping atoms from the graphene lattice at high temperature promote the interlayer migration of carbon atoms, effectively promote the three-dimensional rearrangement and crystallization of the graphite crystal in the graphitization process, thereby greatly improving the graphitization efficiency, the grain size, the order and the crystallization quality of the graphene film, and the heat-conducting and electricity-conducting performance. The application has the characteristics of simple preparation process, high efficiency, easy scale-up, high quality and performance of the obtained graphene film, lays a foundation for the application of graphene in the fields of heat management, electromagnetic shielding, energy storage, nuclear technology and the like, and is expected to be used for efficient graphitization of carbon materials such as graphene fibers.

A solid mass of multiple graphene foam particles wherein at least a particle has a particle size in the range of 10 nm to 10 cm and comprises multiple pores and multiple graphene sheets the form pore walls and the graphene sheets contain a pristine graphene material, having essentially zero % of non-carbon elements, or a non-pristine graphene material having 0.001% to 55% by weight of non-carbon elements wherein said non-pristine graphene is selected from graphene oxide, reduced graphene oxide, graphene fluoride, graphene chloride, graphene bromide, graphene iodide, hydrogenated graphene, nitrogenated graphene, chemically functionalized graphene, or a combination thereof.

A preparation method of a high-orientation graphene-copper composite structure comprises the following steps: (1) pretreatment of a copper substrate: carrying out mechanical polishing and annealing treatment on a copper foil or a copper plate to form a preferred crystal face; (2) an interface confinement structure is constructed, specifically, a confinement layer is deposited or attached to the copper surface, and a confinement space is formed between the confinement layer and the copper surface; (3) graphene growth under the interface confinement: under the CVD (chemical vapor deposition) process condition, a carbon source is introduced into the confinement space, so that graphene preferentially grows on the copper surface and forms a high-orientation continuous film; (4) the confinement layer is removed, specifically, the confinement layer is removed through wet etching or mechanical stripping, and a high-orientation graphene-copper composite structure is obtained; and (5) optional post-treatment: carrying out low-temperature annealing or hot-pressing treatment on the composite structure to enhance the interface bonding force. The invention aims to solve the problems of random graphene orientation, weak interface bonding, difficulty in large-area uniform growth and the like in the existing graphene-copper composite material.

Provided are a cured product containing a single-layer graphene, a single-layer graphene, a preparation method therefor, and an article containing a single-layer graphene. The method for preparing the cured product containing a single-layer graphene includes (a) mixing graphite with a curable material and optionally a first solvent, and curing and molding same to obtain molded granules; (b) heating a system formed by the molded granules and optionally a second solvent, then introducing a gas for pressurization, and then releasing the pressure to obtain expanded granules; and (c) repeating step (a) and (b) several times, with the graphite and the curable material in step (a) replaced with the expanded granules, to obtain a cured product containing a single-layer graphene. The cured product containing a single-layer graphene is carbonized and separated to obtain a single-layer graphene. The article containing a single-layer graphene contains the cured product or the single-layer graphene.

The present invention discloses a layer-number-controllable graphene derived from natural biomass and a preparation method thereof. The preparation method includes pulverizing 1-100 g of biomass to obtain a 50-to 300-mesh biomass scrap, and drying the biomass scrap at 60-100° C. to obtain a biomass precursor; mixing the biomass precursor with a Bronsted acid solution in a solid-liquid ratio of 0.1:10 to 2:100 g / mL, conducting sealing after discharging oxygen and introducing nitrogen, and then conducting heating for a reaction at 75-95° C. for 1-6 hours to obtain a graphene suspension; and conducting post-treatment on the graphene suspension to obtain a stable graphene dispersion, and then drying the stable graphene dispersion to obtain a graphene powder, where the post-treatment includes one or more of filtration washing, dialysis or ultrasonic treatment. According to the preparation method, the layer-number-controllable graphene is prepared by a mild chemical strategy at relatively low temperature with the biomass having high selectivity as a carbon source. The present invention further provides a layer-number-controllable graphene prepared by the method.

An edge-oxidized single-layer graphene and a preparation method thereof are provided. The preparation method includes: mixing a single-layer graphene, a binder, and a dispersant, and drying a resulting slurry to obtain an electrode plate; and subjecting the electrode plate to electrolytic oxidation in an electrolytic cell to obtain the edge-oxidized single-layer graphene; wherein the electrolytic oxidation is conducted under an ultra-low frequency alternating current having a frequency of 0.01 Hz to 0.02 Hz; and the electrolytic oxidation is conducted at a current density of 30 mA·cm−2 to 50 mA·cm−2 for 50 s to 100 s.

The invention discloses a preparation method of a green and environment-friendly graphene modified loofah sponge new material, and relates to the technical field of biomass composite materials. According to the method, uniform loading of graphene in a loofah sponge matrix is realized through innovative processes such as rotary plasma etching, porosity regulation and control through enzymolysis, ultrasonic-microwave synergistic impregnation and calcination and the like. The volume resistivity of the prepared composite material is as low as 0.9 * 10 <-4 > omega.cm, the heat conductivity coefficient reaches 70W / (m.K), and the composite material is stable in performance within the temperature range of-60 DEG C to 220 DEG C and excellent in corrosion resistance. The technical problems that a traditional graphene composite material is insufficient in conductivity, complex in preparation process, poor in environmental protection performance and the like are solved, remarkable technical progress and practical application value are achieved, and the graphene composite material can be widely applied to the fields of new energy, electronic information, medical health and the like.

Provided are a culture scaffold for promoting stem cell differentiation comprising a multilayer graphene film, a method of regulating growth and differentiation of a stem cell using the culture scaffold, and a method of preparing the culture scaffold, where the culture scaffold is capable of promoting the osteogenic differentiation of stem cells as a result of laminating a graphene film without comprising an additional substance, and it may be variously applicable to application fields of stem cells in / outside the body.