CN104831307B - A kind of preparation method of micro-nano graphene film - Google Patents

Abstract

A kind of preparation method of micro-nano graphene film that the present invention is provided, comprises the following steps：With graphite cake as anode, inert metal plate or graphite cake as negative electrode, ultra-pure water or mellitic acid solution as electrolyte, graphite is implemented to be electrolysed, micro-nano carbon material of the diameter between 10 500nm scopes can be obtained in the electrolytic solution；It is evaporated, is heat-treated 30 120min at 400 600 DEG C in the argon gas or nitrogen atmosphere, obtains final product the micro-nano graphene film that thickness is 5 10nm.The process is simple, is easy to operation, and environmental protection, obtained graphene film has diameter dimension small.

Description

A kind of preparation method of micro-nano graphene sheet

technical field

The invention relates to a method for preparing a micro-nano graphene sheet, in particular to a method for preparing a graphene sheet that can be used in areas such as plastic reinforcement, sensing, catalysis, battery anode materials, and stealth, and belongs to the field of nanomaterial preparation.

Background technique

Graphene materials have excellent electrical conductivity, thermal conductivity, and ultra-high strength, and are expected to be widely used in plastic material reinforcement, sensing, optoelectronics, battery electrodes, catalysis, and stealth. At present, there are two main types of large-scale preparation of graphene materials: one is to grow high-quality large-scale graphene films on copper or nickel substrates by chemical vapor deposition; the other is to prepare graphene powders by oxidation-reduction methods. Although the former can obtain high-quality and complete graphene, its cost is high and it is limited to demanding semiconductor industry applications. The latter can be mass-produced due to its relatively simple process and low cost. However, since a large amount of chemical raw materials are needed for graphite oxidation and graphene reduction, a large amount of chemical waste liquid will be generated, which will cause great environmental pollution.

Contents of the invention

Purpose of the invention: the purpose of the present invention is to provide a novel method for preparing nano-micro graphene sheets for the deficiencies in the prior art.

Technical solution: The preparation method of a kind of micro-nano graphene sheet provided by the present invention comprises the following steps: using graphite plate as anode, inert metal plate or graphite plate as cathode, ultrapure water or mellitic acid solution as electrolyte, Graphite is electrolyzed, and micro-nano carbon materials with diameters in the range of 10-500nm can be obtained in the electrolyte; evaporated to dryness, and heat-treated at 400-600°C for 30-120min in an argon or nitrogen atmosphere to obtain a thickness of 5-10nm micro-nano graphene sheets.

Preferably, the anode graphite plate is characterized by: ash content ≤ 50ppm, bulk density ≥ 1.5g/cm ³ , particle size < 500um.

As another preference, the distance between adjacent anode graphite plates and cathode inert metal plates or graphite plates is 1-10 mm.

As another preference, the resistivity of the ultrapure water is above 18MΩ; the concentration of sodium melliticate is 0.1-2mol/L.

As another preference, the electrolysis conditions are: voltage 4-50V, current density 0-300mA/cm ² , electrolysis time 4-96h.

Beneficial effects: Compared with the prior art (chemical vapor deposition method and redox method), the present invention has the following outstanding advantages:

(1) The process is simple, easy to operate, and environmentally friendly. This process does not require expensive vacuum deposition systems required by chemical vapor deposition techniques, does not require specially treated copper or nickel growth substrates, and a high-temperature growth environment of 800-100 ° C, no flammable and explosive gas emissions; and no redox process Metal pollution, toxic gases and hidden dangers of explosion generated in the process. Graphene materials can be obtained through relatively simple electrochemical and heat treatment processes.

(2) the graphene sheet that the present invention makes has smaller diameter size: at present chemical vapor deposition is mainly used in the preparation of large area graphene; The particle size of the raw material is relatively large), and it is difficult to further obtain graphene with a diameter of nanoscale. This technology makes it possible to produce graphene sheets with a diameter of micronano scale through electrochemical and heat treatment.

Description of drawings

Morphology of carbon material in carbon liquid before Fig. 1 heat treatment;

Fig. 2 Morphology and high-resolution fine structure of graphene sheets obtained after heat treatment.

detailed description

Before the present invention materials, methods are described, it is to be understood that this disclosure is not limited to particular methods and materials described, as these may vary. It is also to be understood that the terminology used in the specification is for the purpose of describing these particular forms or embodiments only and is not intended to limit the scope. Unless defined otherwise, all technical or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art.

The graphite plate is used as the anode, the ash content is ≤50ppm, the bulk density is ≥1.5g/cm ³ , and the particle size is <500um. The cathode electrode plate adopts inert metal plate or graphite plate; the distance between adjacent anode graphite plate and cathode plate is 1-10mm. The electrolyte is ultrapure water with a resistivity greater than 18MΩ or an acidic solution of 0.1-2mol/L mellitic acid solution. During electrolysis, the voltage is 4-50V, the current density is 0-300mA/cm ² , and the time is 4-96 hours. After electrolysis, the water in the solution is removed by evaporation. Finally, the solid matter is heat-treated at 400-600° C. for 30-120 minutes in an argon or nitrogen atmosphere.

Specific examples of preparing nanoscale diameter graphene materials using the preparation method of the present invention are given below.

Example 1

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm. Titanium plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 3 mm. The electrolyte is ultrapure water with a resistivity above 18MΩ. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 4V, and the current density is controlled at 0-200mA/cm ² . After 96 hours, a sol of micro-nano carbon particles is obtained. After evaporating water at 80°C, the solid matter was heated in a nitrogen atmosphere at 400°C for 120min to obtain graphene sheets with a diameter of about 10-100nm and a thickness of 5-10nm.

Example 2

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm. Titanium plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 3 mm. The electrolyte is 0.1mol/L mellitic acid solution. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 4V, and the current density is controlled at 100-200mA/cm ² . After 48 hours, a sol of micro-nano carbon particles is obtained. After evaporating the water at 80°C, the solid matter was heated at 400°C for 120min in a nitrogen atmosphere to obtain graphene sheets with a diameter of about 50-1000nm and a thickness of 5-10nm.

Example 3

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm, with ash content ≤ 50ppm, a bulk density ≥ 1.5g/cm ³ , and a particle size of <500um; the cathode electrode plate adopts a thickness of 10mm, a length of 700mm, and a width of 700mm Titanium plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 3 mm. The electrolyte is ultrapure water with a resistivity above 18MΩ. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 50V, and the current density is controlled at 0-300mA/cm ² . After 48 hours, a sol of micro-nano carbon particles is obtained. After evaporating water at 80°C, the solid matter was heated at 600°C in a nitrogen atmosphere for 30 minutes to obtain graphene sheets with a diameter of about 50-500nm and a thickness of 5-10nm.

Example 4

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm, with ash content ≤ 50ppm, a bulk density ≥ 1.5g/cm ³ , and a particle size of <500um; the cathode electrode plate adopts a thickness of 10mm, a length of 700mm, and a width of 700mm Titanium plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 3 mm. The electrolyte is 2mol/L mellitic acid solution. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 50V, and the current density is controlled at 200-300mA/cm ² . After 6 hours, a sol of micro-nano carbon particles is obtained. At 80°C, after evaporating the water to dryness, the solid matter was heated at 400°C in a nitrogen atmosphere for 30 minutes to obtain graphene sheets with a diameter of about 100-1500nm and a thickness of 5-10nm.

Example 5

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm, with ash content ≤ 50ppm, a bulk density ≥ 1.5g/cm ³ , and a particle size of <500um; the cathode electrode plate adopts a thickness of 10mm, a length of 700mm, and a width of 700mm Titanium plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 3 mm. The electrolyte is 2mol/L mellitic acid solution. The power supply is pulse power supply.

After turning on the power, the voltage is controlled at 50V, the current density is controlled at 200-300mA/cm ² , and the frequency is 10kHz. After 6 hours, a sol of micro-nano carbon particles was obtained. At 80°C, after evaporating the water to dryness, the solid matter was heated at 400°C in a nitrogen atmosphere for 30 minutes to obtain graphene sheets with a diameter of about 100-1500nm and a thickness of 5-10nm.

Example 6

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm. plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 1 mm. The electrolyte is ultrapure water with a resistivity above 18MΩ. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 20V, and the current density is controlled at 0-200mA/cm ² . After 60 hours, a sol of micro-nano carbon particles is obtained. After evaporating to dryness at 80°C, the solid matter was heated for 60 minutes in a nitrogen atmosphere at 500°C to obtain graphene sheets with a diameter of about 10-100nm and a thickness of 5-10nm.

Example 7

The anode electrode plate adopts a graphite plate with a thickness of 80mm, a length of 700mm, and a width of 700mm. plates; the spacing between adjacent anode graphite plates and cathode inert metal plates is 10 mm. The electrolyte is ultrapure water with a resistivity above 18MΩ. The power supply is a rectified DC power supply.

After the power is turned on, the voltage is controlled at 30V, and the current density is controlled at 0-200mA/cm ² . After 4 hours, a sol of micro-nano carbon particles is obtained. After evaporating water at 80°C, the solid matter was heated at 500°C in a nitrogen atmosphere for 90 minutes to obtain graphene sheets with a diameter of about 10-100nm and a thickness of 5-10nm.

Claims (3)

1. a kind of preparation method of micro-nano graphene sheet, it is characterized in that: comprise the following steps: take graphite plate as anode, inert metal plate or graphite plate as negative electrode, mellitic acid solution, carry out electrolysis to graphite, in Micro-nano carbon materials with a diameter in the range of 10-500nm can be obtained in the electrolyte; evaporate to dryness, and heat-treat at 400-600°C for 30-120min in an argon or nitrogen atmosphere to obtain micro-nano graphene with a thickness of 5-10nm piece; Wherein, the distance between adjacent anode graphite plates and cathode inert metal plates or graphite plates is 1-3 mm; the concentration of mellitic acid solution is 0.1-2 mol/L. 2. The preparation method of a micro-nano graphene sheet according to claim 1, characterized in that: the anode graphite plate is characterized by: ash content ≤ 50ppm, bulk density ≥ 1.5g/cm ³ , particle size < 500μm. 3 . The preparation method of a micro-nano graphene sheet according to claim 1 , characterized in that the electrolysis conditions are: at a voltage of 4-50V, a current density of 0-300mA/cm ² , and an electrolysis time of 4-96h.