CN113735125B - Carbide derived carbon material and preparation method and application thereof - Google Patents

Abstract

The invention discloses a carbide derived carbon material, a preparation method and application thereof, and a two-dimensional carbide crystal V is prepared by a high-temperature solid phase method ₂ AlC, two-dimensional carbide crystal V ₂ AlC and Lewis acid molten salt CuCl ₂ The carbide derivative carbon material is obtained by mixing and reacting at high temperature, the preparation method has the advantages of simple process steps, mild reaction, easy control, no use of chlorine with strong corrosion and severe toxicity, environmental protection and no pollution, and the prepared carbide derivative carbon material has excellent performance and is suitable for hydrogen storage, catalyst carriers, lithium ion battery electrodes and supercapacitor electrode materials.

Description

A kind of carbide-derived carbon material and its preparation method and application

technical field

The invention relates to the field of nanometer materials, in particular to a carbide-derived carbon material and its preparation method and application.

Background technique

Carbide-Derived Carbon (CDC) is a new type of carbon material obtained by removing non-carbon atoms in the lattice and leaving a skeleton carbon structure using carbide as a precursor. CDC can usually be obtained by selectively etching metal elements using high-temperature chlorine gas. CDC has the characteristics of high specific surface area, adjustable pore size distribution and controllable microstructure, so it has important application value in many fields. In recent years, the carbide precursors used to prepare CDC mainly include binary carbides, ternary carbides, and polymer carbon precursors. The ternary carbides used to prepare CDCs are usually MAX phases.

MAX is a metal carbide or metal nitride containing C or N. Its chemical formula is M _n+1 AX _n , where M represents transition metal elements (Ti, Nb, V, Ta, etc.), and A is mainly the third and elements of the fourth main group (Al, Si, etc.), X is carbon or nitrogen. n=1, 2 or 3. According to the different values of n, the MAX phase can be divided into 211 phases, 312 phases and 413 phases. A new type of two-dimensional nanomaterial called two-dimensional transition metal carbide or nitride (MXene) can be obtained by selectively etching the elements of layer A in the precursor MAX phase by chemical method. In 2003, Gogotsi prepared Ti ₃ SiC ₂ -CDC by high temperature chlorination of Ti ₃ SiC ₂ . This CDC has a larger pore volume and a more precisely adjusted pore size. In addition, Hoffman et al. also systematically studied the preparation process of CDC with ternary carbides Ti ₃ AIC ₂ , Ti ₂ A1C, Ti ₂ A1C _0.5 N _0.5 , and Ta ₂ A1C as precursors, and characterized the structures of the obtained CDCs respectively. feature.

However, the synthesis of CDC is often accompanied by high temperature and requires dangerous chlorine gas to participate in the reaction, which limits its further application. At the same time, most of the MAX precursors used are Ti-based, and there are few studies on the preparation of CDC from V-based MAX precursors.

Contents of the invention

In order to solve the problems in the prior art, the present invention provides a carbide-derived carbon material and its preparation method and application. The two-dimensional carbide crystal V ₂ AlC is prepared by a high-temperature solid-state method, and then the two-dimensional carbide crystal V ₂ AlC is mixed with Lewis acid molten salt CuCl ₂ for high-temperature reaction to obtain carbide-derived carbon materials. The preparation method has simple process steps, mild reaction, easy control, avoids the use of chlorine gas with strong corrosion and toxicity, and is environmentally friendly and non-toxic. Pollution, the prepared carbide-derived carbon material has excellent performance and is suitable for hydrogen storage, catalyst carrier, lithium-ion battery electrode, and supercapacitor electrode material.

In order to achieve the above object, the invention provides a kind of preparation method of carbide-derived carbon material, comprising the following steps:

1) Mix and grind vanadium powder, aluminum powder and graphite powder according to the material ratio of 2:(1-1.5):1 to prepare the precursor mixture;

2) Treat the precursor mixture at a constant temperature of 1300-1600° C. for 2-5 hours under an inert atmosphere to prepare a two-dimensional carbide crystal V ₂ AlC;

3) Mix and grind V ₂ AlC, CuCl ₂ , KCl and NaCl with a substance ratio of 1:(3~5):1:1, and then treat the mixture at a constant temperature of 650~1000°C for 4~10 hours under an inert atmosphere , to get a mixture;

4) adding deionized water to the mixture for centrifugation, adding the obtained precipitate into a sodium persulfate solution and stirring, adding deionized water to wash and vacuum drying to obtain a carbide-derived carbon material.

Further, alcohol is added during grinding in the step 1), and dried after grinding to obtain a precursor mixture.

Further, in the step 2), the precursor mixture is transferred to a tube furnace, and an inert gas is introduced, and the temperature of the tube furnace is raised to 1600 °C at a rate of 4 °C/min, and the temperature is maintained for 2 hours.

Further, in the step 3), the mixture is transferred to a tube furnace, and an inert gas is introduced, and the temperature of the tube furnace is raised to 750° C. at a rate of 10° C./min, and treated at a constant temperature for 5 hours.

Further, the molar ratio of vanadium powder, aluminum powder and graphite powder in the step 1) is 2:1.3:1.

Further, the material ratio of V ₂ AlC, CuCl ₂ , KCl and NaCl in the step 3) is 1:5:1:1.

Further, the purity of the vanadium powder, aluminum powder and graphite powder are all analytically pure, and the graphite powder is artificial graphite powder.

Further, the concentration of the sodium persulfate solution is 1M.

The present invention also provides a carbide-derived carbon material, which is prepared by the above-mentioned preparation method of a carbide-derived carbon material.

The present invention also provides an application of the above-mentioned carbide-derived carbon material as hydrogen storage, catalyst carrier, lithium ion battery electrode, and supercapacitor electrode material.

Compared with the prior art, the present invention first prepares the two-dimensional carbide crystal V ₂ AlC by the high-temperature solid-phase method, and the V ₂ AlC prepared by the high-temperature solid-phase method is a ternary layered compound, and its crystal phase , V atomic layers and Al atomic layers are alternately arranged to form a close-packed hexagonal layered structure, and C atoms fill the octahedral gaps; then use Lewis acid molten salt CuCl ₂ to etch V ₂ AlC, using the ionic state in the molten salt Cu ²⁺ can oxidize Al and V atoms, etch away the Al and V atomic layers in the two-dimensional carbide crystal V ₂ AlC, leaving only C atoms in the end, that is, the carbide-derived carbon CDC material, preparation method and process The steps are simple, the reaction is mild, and it is easy to control. It avoids the use of highly corrosive and highly toxic chlorine gas, and is environmentally friendly and pollution-free. The prepared carbide-derived carbon material has a hydrogen evolution overpotential of 513mV. At the same time, the mass ratio of The capacitance reaches 9.7F/g, and the performance is excellent. It is suitable for hydrogen storage, catalyst carrier, lithium-ion battery electrode, and supercapacitor electrode material. It has important application prospects in many fields.

Description of drawings

Fig. 1 is the XRD diagram of the V ₂ AlC and CDC material prepared in Example 1 of the present invention;

Fig. 2 is the SEM picture of the CDC material that the embodiment of the present invention 1 makes;

Fig. 3 is the electrochemical test result Fig. 1 of the CDC material that embodiment 1 of the present invention makes;

Figure 4 is Figure 2 of the electrochemical test results of the CDC material prepared in Example 1 of the present invention.

Detailed ways

The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. Apparently, the described embodiments are part of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

The invention provides a method for preparing carbide-derived carbon CDC materials. Firstly, a two-dimensional carbide crystal V ₂ AlC is prepared by a high-temperature solid-phase method, and then the V ₂ AlC is etched with Lewis acid molten salt CuCl ₂ to convert the two-dimensional carbonized The Al and V atomic layers in the material crystal V ₂ AlC are etched away, and the CDC material is obtained. Specifically include:

1) Put vanadium powder, aluminum powder and graphite powder into the mortar according to the material ratio of 2:(1~1.5):1, add alcohol to grind, and dry at 35°C for 12 hours to obtain the precursor Mixing; preferably, the amount ratio of vanadium powder, aluminum powder and graphite powder is 1:1.3:1; preferably, the purity of vanadium powder, aluminum powder and graphite powder is analytically pure, and graphite powder is artificial graphite powder ;

2) Transfer the precursor mixture to a tube furnace, pass in an inert gas, raise the temperature of the tube furnace to 1300-1600 °C at 4-10 °C/min, and treat at a constant temperature for 2-5 hours to obtain a two-dimensional carbide crystal V ₂ AlC; preferably, the tube furnace is heated up to 1600°C at 4°C/min, and treated at a constant temperature for 2 hours; the inert gas is a flowing argon atmosphere;

3) Put the V ₂ AlC, CuCl ₂ , KCl and NaCl with the molar ratio of 1:(3~5):1:1 in a mortar and grind for 2 minutes, transfer the mixture to a tube furnace, and put it into Inert gas, the temperature of the tube furnace is raised to 650-1000°C at 10°C/min, and the constant temperature is treated for 4-10h; preferably, the temperature of the tube furnace is raised to 750°C at 10°C/min, and the constant temperature is treated for 5h; preferably, V ₂ AlC , CuCl ₂ , KCl and NaCl have a molar ratio of 1:5:1:1;

4) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times, add the precipitate to 1M sodium persulfate solution and stir After 4 hours, add deionized water to wash, and finally vacuum-dry at 60° C. for 12 hours to obtain a CDC material.

The present invention also provides a carbide-derived carbon material prepared by the above method. The CDC material is applied to hydrogen storage, catalyst carrier, lithium ion battery electrode, and supercapacitor electrode material, and has important application prospects in many fields.

The present invention will be described in detail below through specific examples.

Example 1:

1) Mix and grind vanadium powder, aluminum powder and graphite powder with a particle size of 200 mesh for 10 minutes, wherein the molar ratio of vanadium, aluminum and carbon elements is 2:1.3:1, place them in a crucible, and then place them in flowing argon Sintering is carried out in a tube furnace with a heating rate of 4 °C/min to 1500 °C, and the holding time is 2 hours. The parameters of the tube furnace with flowing argon are as follows: the pressure of argon is 0.07 MPa, and the flow rate of argon is 40 cc/min , the furnace was cooled to room temperature to obtain bulk precursor MAX phase compound V ₂ AlC. Grind the bulk powder and sieve, the sieve specification is 40 microns.

2) V ₂ AlC, CuCl ₂ , NaCl and KCl were ground in a mortar for 2 minutes according to the ratio of the substances of 1:5:1:1, and the ground mixture was placed in a crucible, and then placed in a flowing argon atmosphere. Sintering was carried out in a tube furnace at a heating rate of 10°C/min to 750°C, the holding time was 5h, and the furnace was cooled to room temperature to obtain a mixture of CDC and molten salt.

3) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times. The precipitate was added to 1M sodium persulfate solution and stirred for 4 hours, then deionized water was added to wash, and finally vacuum-dried at 60°C for 12 hours to obtain the CDC material.

XRD analysis was carried out on the V ₂ AlC and CDC materials prepared in Example 1, see Fig. 1 , it can be seen from Fig. 1 that the original V ₂ AlC was completely etched, leaving only the carbon layer, that is, CDC.

SEM analysis was carried out on the CDC material prepared in Example 1, see FIG. 2 , it can be seen from FIG. 2 that the CDC presents an obvious layered structure.

The CDC material prepared in Example 1 was electrochemically tested and analyzed, see Figure 3, it can be seen from Figure 3 that CDC has obvious electrocatalytic hydrogen evolution activity, and the current density _reaches 10mA cm ^-2 in _0.5MH2SO4 solution Only 513mV overpotential is required.

Electrochemical analysis is carried out to the CDC material that embodiment 1 makes, referring to Fig. 4, can find out from Fig. 4 that CDC can be used as positive electrode material, in 3MH ₂ SO ₄ solution, mass specific capacitance under 2mV/s scanning speed It reaches 9.7F/g, and the mass specific capacitance reaches 6.6F/g at a scanning speed of 10mV/s.

Example 2:

1) Mix and grind vanadium powder, aluminum powder and graphite powder with a particle size of 200 mesh for 10 minutes, wherein the molar ratio of vanadium, aluminum and carbon elements is 2:1.3:1, and place them in a crucible. Then place it in a tube furnace with flowing argon at a heating rate of 4°C/min to 1500°C for sintering, the holding time is 2h, the parameters of the tube furnace with flowing argon are as follows: the pressure of argon is 0.07MPa, The flow rate is 40cc/min, and the furnace is cooled to room temperature to obtain the bulk precursor MAX phase compound V ₂ AlC. Grind the bulk powder and sieve, the sieve specification is 40 microns.

2) V ₂ AlC, CuCl ₂ , NaCl, and KCl were ground in a mortar for 2 minutes according to the ratio of substances of 1:3:1:1, and the ground mixture was placed in a crucible, and then placed in a flowing argon atmosphere. Sintering was carried out in a tube furnace at a heating rate of 10°C/min to 750°C, the holding time was 5h, and the furnace was cooled to room temperature to obtain a mixture of CDC and molten salt.

3) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times. The precipitate was added to 1M sodium persulfate solution and stirred for 4 hours, then deionized water was added to wash, and finally vacuum-dried at 60°C for 12 hours to obtain the CDC material.

Example 3:

1) Mix and grind vanadium powder, aluminum powder and graphite powder with a particle size of 200 mesh for 10 minutes, wherein the molar ratio of vanadium, aluminum and carbon elements is 2:1.3:1, and place them in a crucible. Then place it in a tube furnace with flowing argon at a heating rate of 4°C/min to 1500°C for sintering, the holding time is 2h, the parameters of the tube furnace with flowing argon are as follows: the pressure of argon is 0.07MPa, The flow rate is 40cc/min, and the furnace is cooled to room temperature to obtain the bulk precursor MAX phase compound V ₂ AlC. Grind the bulk powder and sieve, the sieve specification is 40 microns.

2) V ₂ AlC, CuCl ₂ , NaCl, and KCl were ground in a mortar for 2 minutes according to the ratio of substances in the amount of 1:5:1:1, and the ground mixture was placed in a crucible, and then placed in a flowing argon atmosphere. Sintering was carried out in a tube furnace at a heating rate of 10°C/min to 650°C, the holding time was 5h, and the furnace was cooled to room temperature to obtain a mixture of CDC and molten salt.

3) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times. The precipitate was added to 1M sodium persulfate solution and stirred for 4 hours, then deionized water was added to wash, and finally vacuum-dried at 60°C for 12 hours to obtain the CDC material.

Example 4:

1) Add vanadium powder, aluminum powder and graphite powder together into a mortar with a ratio of 2:1:1, add alcohol to grind, and dry at 35°C for 12 hours to obtain a precursor mixture;

2) Transfer the precursor mixture to a tube furnace, pass in an inert gas, raise the temperature of the tube furnace to 1300 °C at 4 °C/min, and treat at a constant temperature for 5 hours to obtain a two-dimensional carbide crystal V ₂ AlC;

3) Put V ₂ AlC, CuCl ₂ , KCl and NaCl with a molar ratio of 1:3:1:1 in a mortar and grind for 2 min, then transfer the mixture to a tube furnace, pass inert gas, and tube The furnace is heated up to 650°C at 10°C/min, and treated at constant temperature for 10h;

4) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times, add the precipitate to 1M sodium persulfate solution and stir After 4 hours, add deionized water to wash, and finally vacuum-dry at 60° C. for 12 hours to obtain a CDC material.

Example 5:

1) Add vanadium powder, aluminum powder and graphite powder together into a mortar according to the material ratio of 2:1.5:1, add alcohol to grind, and dry at 35°C for 12 hours to obtain a precursor mixture;

2) Transfer the precursor mixture to a tube furnace, feed inert gas, raise the temperature of the tube furnace to 1600 °C at 10 °C/min, and treat at a constant temperature for 2 hours to obtain a two-dimensional carbide crystal V ₂ AlC;

3) Put V ₂ AlC, CuCl ₂ , KCl and NaCl with a molar ratio of 1:5:1:1 in a mortar and grind for 2 minutes, then transfer the mixture to a tube furnace, pass inert gas, and tube The furnace is heated up to 1000°C at 10°C/min, and treated at constant temperature for 4 hours;

4) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times, add the precipitate to 1M sodium persulfate solution and stir After 4 hours, add deionized water to wash, and finally vacuum-dry at 60° C. for 12 hours to obtain a CDC material.

Embodiment 6:

1) Add vanadium powder, aluminum powder and graphite powder together into a mortar according to the material ratio of 2:1.2:1, add alcohol to grind, and dry at 35°C for 12 hours to obtain a precursor mixture;

2) Transfer the precursor mixture to a tube furnace, pass in an inert gas, raise the temperature of the tube furnace to 1400 °C at a rate of 6 °C/min, and treat at a constant temperature for 3 hours to obtain a two-dimensional carbide crystal V ₂ AlC;

3) Put V ₂ AlC, CuCl ₂ , KCl and NaCl with a molar ratio of 1:4:1:1 in a mortar and grind for 2 minutes, then transfer the mixture to a tube furnace, pass inert gas, and tube The furnace is heated up to 850°C at 10°C/min, and treated at constant temperature for 6 hours;

4) Put the obtained mixture in a 50ml centrifuge tube, add deionized water and centrifuge at 3500rpm/min for 3min, discard the supernatant, repeat 3 times, add the precipitate to 1M sodium persulfate solution and stir After 4 hours, add deionized water to wash, and finally vacuum-dry at 60° C. for 12 hours to obtain a CDC material.

In the present invention, the layered vanadium-based MAX phase compound V ₂ AlC is uniformly mixed with Lewis acid molten salt CuCl ₂ , placed in a tube furnace for high-temperature reaction under a flowing argon atmosphere, and then cleaned with deionized water and sodium persulfate solution , drying the washed sample in a vacuum environment at a certain temperature for a certain period of time to obtain a carbide-derived carbon material. The method for preparing carbide-derived carbon CDC of the present invention does not involve toxic and harmful Cl ₂ , and only uses CuCl ₂ to completely corrode the Al and V layers in the V ₂ AlC phase to obtain CDC, avoiding the use of strong corrosion and severe Toxic chlorine gas, green and pollution-free, mild reaction, easy to control, simple operation steps, suitable for large-scale production. Therefore, it has important application prospects in many fields, such as hydrogen storage, catalyst support, lithium-ion battery electrodes, and supercapacitor electrode materials.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it still The technical solutions described in the foregoing embodiments can be modified, or some or all of the technical features can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. A method for preparing a carbide-derived carbon material, comprising the steps of:

1) Mixing and grinding vanadium powder, aluminum powder and graphite powder according to the mass ratio of 2 (1-1.5) to 1 to prepare a precursor mixed material;

2) The precursor mixture is treated for 2 to 5 hours at the constant temperature of 1300 to 1600 ℃ under the inert atmosphere to prepare the two-dimensional carbide crystal V ₂ AlC；

3) The mass ratio of the substances is 1: (3-5): 1: v of 1 ₂ AlC、CuCl ₂ Mixing and grinding KCl and NaCl, and then processing the mixture at the constant temperature of 650-1000 ℃ for 4-10 hours under inert atmosphere to obtain a mixture;

4) Adding deionized water into the mixture for centrifugal separation, adding the obtained precipitate into a sodium persulfate solution for stirring, adding deionized water for cleaning, and carrying out vacuum drying to obtain the carbide-derived carbon material.

2. The method for preparing a carbide derived carbon material as claimed in claim 1, wherein alcohol is added during the grinding in step 1), and the precursor mixture is prepared by drying after grinding.

3. The method for preparing a carbide derived carbon material according to claim 1, wherein the precursor mixture in the step 2) is transferred to a tube furnace, inert gas is introduced, the tube furnace is heated to 1600 ℃ at 4 ℃/min, and the tube furnace is subjected to constant temperature treatment for 2 hours.

4. The method for preparing a carbide derived carbon material according to claim 1, wherein the mixture in the step 3) is transferred to a tube furnace, inert gas is introduced, the tube furnace is heated to 750 ℃ at 10 ℃/min, and the tube furnace is subjected to constant temperature treatment for 5 hours.

5. The method for preparing a carbide-derived carbon material according to claim 1, wherein the mass ratio of the vanadium powder, the aluminum powder and the graphite powder in the step 1) is 2:1.3:1.

6. The method for producing a carbide derived carbon material as claimed in claim 1, wherein V in step 3) ₂ AlC、CuCl ₂ The mass ratio of KCl to NaCl was 1:5:1:1.

7. the method for preparing a carbide derived carbon material according to claim 1, wherein the purities of the vanadium powder, the aluminum powder and the graphite powder are all analytically pure, and the graphite powder is artificial graphite powder.

8. A method of preparing a carbide derived carbon material according to claim 1, wherein the concentration of the sodium persulfate solution is 1M.

9. A carbide derived carbon material prepared by the method of any one of claims 1 to 8.

10. Use of the carbide derived carbon material of claim 9 as hydrogen storage, catalyst support, lithium ion battery electrode, and supercapacitor electrode material.