黄色一级免费_别揉我胸啊嗯上课_在线看片黄_日本人一级毛片视频

Preparation of powdered graphene, if graphene powder is produced?

Release date: January 17, 2017 reading times: 38

1、 What is graphene?

Graphene is a kind of honeycomb like flat film formed by SP2 hybridization of carbon atoms. It is a quasi two-dimensional material with only one atomic layer thickness, so it is also called single atomic layer graphite.Its thickness is about 0.335nm, and there are different fluctuations according to different preparation methods. Generally, it is about 1nm high in the vertical direction, and about 10nm to 25nm wide in the horizontal direction. It is the basic structural unit of all carbon crystals (zero dimensional fullerene, one-dimensional carbon nanotubes, three-dimensional body oriented graphite) except diamond.

2、 What are the types of graphene?

monolayer graphene

Graphene: refers to a two-dimensional carbon material composed of a layer of carbon atoms with a benzene ring structure (i.e. hexagonal honeycomb structure) periodically and tightly packed.

Bilayer graphene

Bilayer or double layer graphene: refers to a kind of two-dimensional carbon material composed of two layers of carbon atoms stacked in different stacking ways (including ab stacking, AA stacking, AA 'stacking, etc.) with benzene ring structure (i.e. hexagonal honeycomb structure) periodically and tightly.

Less graphene

Few layer: refers to a two-dimensional carbon material which is composed of 3-10 layers of carbon atoms which are periodically and tightly stacked in benzene ring structure (i.e. hexagonal honeycomb structure) in different stacking ways (including ABC stacking, ABA stacking, etc.).

Multilayer or thick graphene

Multi layer graphene: refers to a kind of two-dimensional carbon material which is composed of carbon atoms piled up periodically and tightly in different stacking ways (including ABC stacking, ABA stacking, etc.).

3、 What is the preparation method of powdered graphene?

1. mechanical stripping method

Mechanical peeling is a method to obtain graphene thin layer materials by using the friction and relative motion between the object and graphene.This method is easy to operate, and the graphene obtained usually keeps a complete crystal structure. In 2004, two British scientists used transparent tape to strip natural graphite layer by layer to obtain graphene, which was also classified as mechanical stripping method. This method was once considered to be low production efficiency and unable to be industrialized and mass produced.

In recent years, the industry has carried out a lot of research and development innovation on the production method of graphene. At present, several companies in Xiamen, Guangdong and other provinces have overcome the bottleneck of low-cost large-scale production of graphene, and use the mechanical stripping method to industrialize the production of graphene with low cost and high quality.

2, redox method

Graphite oxide is prepared by oxidizing natural graphite with sulfuric acid, nitric acid and other chemical reagents, potassium permanganate, hydrogen peroxide and other oxidants, increasing the spacing between graphite layers, inserting oxides between graphite layers.Then the reactant was washed and the washed solid was dried at low temperature to prepare graphite oxide powder.Graphene oxide was prepared by physical stripping and high temperature expansion.At last, graphene oxide (RGO) was reduced by chemical method.This method is simple in operation, high in output, but low in product quality.The oxidation-reduction method uses sulfuric acid, nitric acid and other strong acids, which is dangerous. It also needs to use a large number of water for cleaning, which brings great environmental pollution.

Graphene prepared by oxidation-reduction method has rich oxygen-containing functional groups and is easy to be modified.However, it is difficult to control the oxygen content of graphene oxide after reduction when reducing graphene oxide. At the same time, graphene oxide will continue to reduce under the influence of sunlight, high temperature in the carriage during transportation and other external factors. Therefore, the quality of graphene produced by oxidation-reduction method is often inconsistent and difficult to control.

At present, many people confuse the concepts of graphite oxide, graphene oxide and reduced graphene oxide.The color of graphite oxide is brown, which is a polymer of graphite and oxide.Graphene oxide is the product of stripping graphene oxide to a single, double or oligo layer, which contains a large number of oxygen-containing groups. Therefore, graphene oxide is not conductive, and its properties are active. In the use process, especially in the processing of high-temperature materials, it will continuously reduce and release sulfur dioxide and other gases.The product after reduction of graphene oxide can be called graphene (reduced graphene oxide).

3SiC epitaxy

SiC epitaxy is to sublime the silicon atom out of the material in the high temperature environment of ultra-high vacuum, and reconstruct the remaining C atom by self-assembly, so as to obtain graphene based on SiC substrate.High quality graphene can be obtained by this method, but this method requires high equipment.

4、 Powder graphene preparation furnace rsmxl series graphene expansion furnace

Rsmxl graphene expansion furnace is designed for the pilot production line of graphene, and is specially used for the preparation of powdered graphene

The whole furnace body of rsmxl graphene expansion furnace adopts Haval vertical structure, which is convenient for opening and closing

Rsmxl graphene expansion furnace adopts high-purity gas quartz tube as furnace, alumina fiber products are insulated, can pre vacuumize, pass protection and reaction gas.

The temperature control of rsmxl graphene expansion furnace is controlled by imported single circuit intelligent temperature controller, which has the characteristics of high temperature control accuracy and temperature stability.

5、 Contact information of manufacturer of powder graphene preparation furnace