CN104674383A - Carbon nano fiber aerogel electrostatic spinning construction method - Google Patents

Abstract

The invention provides an electrospinning construction method of carbon nanofiber airgel, which belongs to the technical field of nanomaterials. The specific steps are as follows: Step a) Prepare the electrospinning solution; Step b) Select an appropriate solvent to directly receive the electrospun nanofibers to obtain a nanofiber solution; Step c) Freeze the nanofiber solution, and then place it in a freeze dryer drying to obtain nanofiber aerogel; step d) preoxidizing, carbonizing and activating the nanofiber aerogel to obtain carbon nanofiber aerogel. The electrospinning construction method of carbon nanofiber airgel provided by the present invention is not only simple and easy to implement, but also has good repeatability, and the composition and structure of the prepared carbon nanofiber airgel are easy to control, and composite carbon nanofibers with various structures can be constructed Aerogels to meet different needs in practical applications.

Description

Electrospinning construction method of carbon nanofiber airgel

technical field

The invention relates to the technical field of nanomaterials, in particular to an electrospinning construction method of carbon nanofiber airgel.

Background technique

Carbon airgel is a new lightweight nanoporous material first discovered by Pekblb in the United States. Its basic characteristics are high porosity, large specific surface area and wide range of density changes. It has special properties in electrical, thermal and optical aspects, and has a wide range of applications. application prospects. For example, it can be used as supercapacitor, catalyst carrier, hydrogen storage material, electrode material, absorbent and gas detector, etc. Among them, light weight and doped carbon aerogels have great application prospects. For example, ultralight nitrogen-doped graphene structures are used as absorbers and supercapacitor electrodes, exhibiting extremely large absorption capacity and special capacitance. Carbon aerogels doped with metals have higher hydrogen storage performance.

The prior art discloses a variety of methods for preparing carbon aerogels, but most of the methods are difficult to prepare carbon aerogels doped with multiple components in one step, and it is not easy to control the structure of carbon aerogels. Therefore, its wider application is limited.

Electrospinning nanofibers is to charge the polymer solution with high-voltage static electricity. When the electric field force is large enough, the polymer droplets overcome the surface tension to form a fine jet stream, and the polymer jet is stretched and thinned, while bending and splitting. Evaporate or solidify and deposit on a receiver plate to form nanofibers. Electrospinning nanofiber technology can integrate multiple components into the same fiber to prepare composite nanofibers, which can realize the preparation of polymer/polymer, polymer/inorganic and inorganic/inorganic composite fibers. In addition, by changing the preparation parameters (such as changing the nozzle structure, controlling the experimental conditions, etc.), electrospinning technology can prepare nanofiber materials with various structures (such as solid, hollow, core-shell structure microfibers or spider webs). structure of two-dimensional fiber membrane, etc.). Currently, most electrospinning techniques use metallic materials as receivers. Therefore, the result is generally a nanofiber film, and to obtain a nanofiber solution, the nanofiber film must be dispersed in an appropriate solvent again. This is not only time-consuming, but also the fiber membrane is difficult to disperse uniformly and is easy to break during dispersion.

Contents of the invention

To solve the technical problem of difficult one-step and simple preparation of carbon aerogel with multi-component doping and controllable structure in the current carbon aerogel preparation method, the present invention discloses a kind of electrospinning of carbon nanofiber aerogel A construction method, the method can simply and quickly prepare multi-component, structurally diverse carbon nanofiber airgel, significantly improve the performance of the carbon nanofiber airgel, meet different needs in reality, and expand its application prospects.

In order to achieve the above object, the following steps that the present invention adopts:

Step a) preparing an electrospinning solution;

Step b) selecting an appropriate solvent to directly receive the electrospun nanofibers to obtain a nanofiber solution;

Step c) freezing the nanofiber solution in a fixed shape, and then placing it in a freeze dryer to dry to obtain the nanofiber airgel;

Step d) Preoxidizing, carbonizing and activating the nanofiber airgel to obtain the carbon nanofiber airgel.

The advantages of the present invention are

1) The electrospun nanofibers are directly received by an appropriate solvent, and a uniformly dispersed nanofiber solution can be obtained in one step, and the nanofibers will not break and maintain good continuity, which is conducive to improving the performance of carbon nanofiber airgel.

2) The carbon nanofiber airgel prepared by this method has a wide range of raw materials, not only polymer materials, but also various organic/inorganic composite materials.

3) The carbon nanofiber airgel prepared by this method is prepared by electrospinning technology. Therefore, multiple components can be easily integrated into the same fiber to prepare composite nanofibers, which can effectively improve the performance of carbon nanofiber airgel.

4) The structure of carbon nanofiber airgel prepared by this method is controllable (such as whether the fiber is hollow, fiber diameter, specific surface area and density, etc.), so carbon nanofiber airgel with the best structure can be prepared according to different needs.

Description of drawings

Figure 1 is an optical diagram of the carbon nanofiber airgel under the conditions of Example 1.

Fig. 2 is a scanning electron micrograph (SEM) of the carbon nanofiber airgel under the conditions of Example 1.

Detailed ways

The present invention will be further described in conjunction with the accompanying drawings and specific embodiments.

Embodiment one

1) Preparation of spinning solution: Weigh 2 g of polyacrylonitrile (PAN) powder and 0.3 g of graphene oxide (GO) into a 100 mL Erlenmeyer flask containing 20 g of dimethylformamide (DMF) solvent placed in a water bath at 60 °C, heated and stirred until dissolved, and configured as a PAN-GO mixed solution.

2) Preparation of nanofibers: The electrospinning solution in step 1) was placed in a 10 ml syringe, and the nanofibers were collected using a plastic container filled with water as a nanofiber receiver. Spinning parameters are: voltage 15 kV, spinneret inner diameter 0.6 mm, spinning solution flow rate 0.9 mL/h, distance from spinneret to receiving water surface 15 cm, receiving time 3 h, environmental conditions: temperature 30±5 ℃ , the relative humidity is 50±5%, and the receiver moves back and forth at a speed of 0.5 cm/s.

3) Preparation of nanofiber airgel: shape the nanofiber solution collected in step 2 according to the required density and shape, and then freeze it in a -4 °C refrigerator for 5 h; then freeze the formed nanofiber Dry in a freeze dryer for 2 days to obtain nanofiber airgel.

4) Preparation of carbon nanofiber airgel: place the nanofiber airgel in step 3 in an oven at 280 °C for 60 min; then in a tubular muffle furnace, under the protection of N ₂ , After heating up to 600℃ at the rate of ℃/min, keep it for 0.5 h; then raise the temperature to 900 ℃ at the rate of 5 ℃/min, activate for 0.5 h in the CO ₂ environment, and finally cool down to room temperature at the rate of 5 ℃/min , to obtain carbon nanofiber aerogels containing graphene.

5) Capacitance performance test of carbon nanofiber aerogel: the carbon nanofiber aerogel in step 4 was used as the working electrode. The Ag/AgCl electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. In 1 mol/L KOH electrolyte, the classic three-electrode system was used to conduct cyclic voltammetry and charge-discharge tests at the electrochemical workstation.

Embodiment two

1) Preparation of spinning solution: Weigh 2 g of polyacrylonitrile (PAN) powder and 0.1 g of ferric chloride (FeCl ₃ ), add them into a 100 mL conical tube containing 20 g of dimethylformamide (DMF) solvent Place in a 60°C water bath, heat and stir until dissolved, and configure it as a PAN-FeCl ₃ mixed solution.

2) Preparation of nanofibers: The electrospinning solution in step 1) was placed in a 10 ml syringe, and the nanofibers were collected using a plastic container filled with water as a nanofiber receiver. Spinning parameters are: voltage 15 kV, spinneret inner diameter 0.6 mm, spinning solution flow rate 0.9 mL/h, distance from spinneret to receiving water surface 15 cm, receiving time 3 h, environmental conditions: temperature 30±5 ℃ , the relative humidity is 50±5%, and the receiver moves back and forth at a speed of 0.5 cm/s.

3) Preparation of nanofiber airgel: shape the nanofiber solution collected in step 2 according to the required density and shape, and then freeze it in a -4 °C refrigerator for 5 h; then freeze the formed nanofiber The blocks were dried in a freeze dryer for 2 days to obtain nanofiber airgel.

4) Preparation of carbon nanofiber airgel: place the nanofiber airgel in step 3 in a tubular muffle furnace, heat up to 600°C at a rate of 5°C/min under the protection of N ₂ , and keep 0.5 h; then heated up to 800 °C at a rate of 5 °C/min, activated for 0.5 h in a water vapor environment, and finally cooled to room temperature at a rate of 3 °C/min to obtain iron-doped carbon nanofiber airgel .

5) Capacitance performance test of carbon nanofiber aerogel: the carbon nanofiber aerogel in step 4 was used as the working electrode. The Ag/AgCl electrode was used as the reference electrode, and the platinum wire was used as the counter electrode. In 1 mol/L KOH electrolyte, the classic three-electrode system was used to conduct cyclic voltammetry and charge-discharge tests at the electrochemical workstation.

Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Making various changes is within the protection scope of the present invention.

Claims (7)

1. The electrospinning construction method of carbon nanofiber airgel, it is characterized in that comprising the following steps: Step a) preparing an electrospinning solution; Step b) selecting an appropriate solvent to directly receive the electrospun nanofibers to obtain a nanofiber solution; Step c) freezing the nanofiber solution in a fixed shape, and then placing it in a freeze dryer to dry to obtain the nanofiber airgel; Step d) Preoxidizing, carbonizing and activating the nanofiber airgel to obtain the carbon nanofiber airgel. 2. The electrospinning construction method of carbon nanofiber airgel according to claim 1, characterized in that the electrospinning liquid in the step a) comprises polymer solution, inorganic solution, polymer/inorganic compound Solution; its polymer solution contains polyacrylonitrile, polyamide, polycarbonate, polyurethane, polyurethane urea, polyvinyl chloride, polyvinylidene fluoride, polyethylene terephthalate, polybutylene terephthalate One or more mixtures of ester, polystyrene, polymethacrylate, polysulfone and polyethersulfone, etc., and their modified polymers; inorganic substances include carbon nanotubes, graphene oxide, graphene, Nanoparticles and nanoparticle precursors, etc. 3. The electrospinning construction method of carbon nanofiber airgel according to claim 1, characterized in that the specific step of step b) is, according to the physical and chemical properties of the spun nanofibers, select an appropriate solvent to place In the receiving container, a nanofiber solution is formed in one step; wherein the solvent includes water, ethanol, organic solvent, and their mixed solution and the like. 4. The electrospinning construction method of carbon nanofiber airgel according to claim 1, characterized in that the specific step of step c) is to freeze the fully dispersed nanofiber solution in liquid nitrogen for 10- 60 min, or freeze in a refrigerator at -4 to -20°C for 1 to 12 hours, and then dry the shaped nanofibers in a freeze dryer for 1 to 3 days to obtain nanofiber aerogels. 5. The electrospinning construction method of carbon nanofiber airgel according to claim 1, characterized in that the specific step of step d) is to place the nanofiber airgel at 180-350 °C In the oven, pre-oxidize for 10-120 min; then in the muffle furnace, under the protection of inert gas, the temperature is raised to 500-700 ℃ at a rate of 1-8 ℃/min, and then kept for 0.5-3 h; The temperature is raised to 750-1200 ℃ at a rate of 8 ℃/min, and activated for 0.5-3 h under the condition of active gas; finally, the temperature is cooled to room temperature at a rate of 1-5 ℃/min to obtain carbon nanofiber airgel. 6. The electrospinning construction method of carbon nanofiber airgel according to claim 1, characterized in that substances with strong mechanical properties can be added to the nanofiber solution in step b), or the nanofibers can be cross-spun Linking agent to enhance the mechanical strength of carbon nanofiber airgel. 7. The electrospinning construction method of carbon nanofiber airgel according to claim 1, which is characterized in that it can be used to prepare carrier materials, adsorption materials, hydrogen storage materials, capacitor materials, electrode materials and pressure sensors.