CN114907566A - A kind of polyimide-metal single-atom composite material and its preparation method and application - Google Patents

Abstract

The invention provides a polyimide-metal single-atom composite material, a preparation method and application thereof, and belongs to the technical field of polymer nanocomposite materials. Firstly, polyamic acid is coated on a carrier material, and it is thermally imidized to obtain a polyimide/carrier composite material, and then single metal atoms are supported on the polyimide/carrier material by atomic layer deposition. On the carrier composite material, a polyimide-metal single-atom composite material supported on the carrier material is finally obtained. Compared with the previous polyimide-metal nanoparticle composite materials, the polyimide-metal single-atom composite material prepared by this method can realize the atomic-level dispersion of metal components, so that the metal utilization rate is greatly improved. promote. In addition, the preparation process is simple and easy to operate, and the prepared polyimide-metal single-atom composite material has good comprehensive properties and has extremely broad application potential.

Description

A kind of polyimide-metal single-atom composite material and its preparation method and application

technical field

The invention belongs to the technical field of polymer nanocomposite materials, and in particular relates to a polyimide-metal single-atom composite material and a preparation method and application thereof.

Background technique

Polyimide is a special engineering plastic with the advantages of good molding performance, high mechanical strength and good thermal stability. It is widely used in various fields of the national economy, such as catalysis, thermal conductivity, dielectric energy storage, electromagnetic wave shielding and absorption. wave, electrochemical energy storage, etc. By compounding polyimide and metal to obtain a polyimide/metal nanoparticle composite material, its performance can be further improved. Nevertheless, metal nanoparticles, especially noble metal nanoparticles (such as platinum, ruthenium, iridium, etc.) are expensive, which can seriously increase the cost of composite materials. Compared with metal nanoparticles, metal single atoms have unique structural properties and fully exposed active sites, showing significant performance enhancements in various application fields. At the same time, this reduces the metal loading to reduce the cost of the composite material.

SUMMARY OF THE INVENTION

Aiming at the problems and deficiencies in the prior art, the present invention provides a polyimide-metal single-atom composite material and a preparation method and application thereof. The polyimide anchors the metal single atom, and the metal single atom has a unique structure. characteristics and fully exposed active site.

A first aspect of the present invention provides a method for preparing a polyimide-metal single-atom composite material, the method comprising the following steps:

(i) coating the polyamic acid solution on the carrier material, putting it into a tube furnace or a muffle furnace, and performing step heating to prepare a polyimide/carrier composite material;

(ii) supporting single metal atoms on the polyimide/support composite material by atomic layer deposition to obtain a polyimide-metal single atom composite material supported on the support material.

In an implementation case, the preparation method of the polyamic acid solution includes: dissolving diamine monomer in a reaction solvent, introducing nitrogen gas, adding dianhydride monomer in an ice-water bath or stirring at room temperature to prepare a polyamic acid solution.

In an embodiment, the molar ratio of the diamine monomer and the dianhydride monomer is 1.0:1.0-1.0:1.1.

In an implementation case, the mass concentration of the polyamic acid solution is 3%-15%, and the solvent of the polyamic acid solution includes N,N-dimethylformamide, N,N-dimethylethyl acetate One or more of amide or N-methylpyrrolidone.

In an implementation case, the diamine monomer includes one or more of p-phenylenediamine, benzidine, diaminodiphenyl ether, and diaminobenzophenone, preferably diaminodiphenyl ether .

In an implementation case, the dianhydride monomer includes one of pyromellitic anhydride, pyromellitic dianhydride, hexafluoro dianhydride, pyromellitic dianhydride, and benzophenone tetracarboxylic dianhydride Or more than one, preferably pyromellitic dianhydride.

In an embodiment, the reaction solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, preferably N, N-dimethylformamide.

In an embodiment, the dropwise amount of the polyamic acid solution in the step (i) is 10-40 μL cm ⁻² .

In an implementation case, the carrier material in the step (i) includes one of carbon paper, carbon aerogel, carbon felt, carbon fiber, and the like.

In an implementation case, the temperature nodes of the step (i) are: 70°C, 100°C, 200°C, 300°C, 350°C in sequence, and the heating rate is 2-5°Cmin ^-1 , Each temperature point is kept for 50-60min.

In an implementation case, the heating rate of the stepwise temperature rise in the step (i) is 5°C min ^-1 , and each temperature node is kept for 1 hour.

In an implementation case, the metal species in the atomic layer deposition step in the step (ii) includes any one of platinum, ruthenium, iridium, iron, cobalt, copper, molybdenum, and the like.

In an implementation case, in the atomic layer deposition method in the step (ii), the program parameters are: the temperature of the reaction chamber is 280-350°C, the temperature of the source bottle is 70-85°C, the flow rate of the source line is 120-150sccm, the oxygen The line flow is 50-80 sccm, the hydrogen line flow is 0-120 sccm, and the deposition times are 25-200 cycles.

On the other hand, the present invention also provides a polyimide-metal single-atom composite material, which is prepared by the above method.

In an embodiment, the surface of the polyimide-metal single-atom composite material has metal single atoms.

In an implementation case, in the polyimide-metal single-atom composite material, the loading amount of the metal single-atom is not less than 0.015 wt %.

In an implementation case, in the polyimide-metal single-atom composite material, the loading amount of the metal single-atom is 0.015wt%-0.500wt%.

On the other hand, the present invention also provides an application of the above preparation method or an application of a polyimide-metal single-atom composite material, such as in catalysis, heat conduction, dielectric energy storage, electromagnetic wave shielding and wave absorption, electrochemical storage applications in fields such as energy.

Compared with the prior art, the beneficial effects of the present invention are:

1. The preparation method of the polyimide-metal single-atom composite material adopted in the present invention is simple and feasible, and a composite material with good dispersion of different single atoms can be obtained by introducing different precursor metal sources.

2. Compared with the polyimide-metal nanoparticle composite material in the prior art, under the same catalytic effect, the metal content of the polyimide-metal single-atom composite material adopted in the present invention is lower, and the metal utilization rate is lower. higher, which can effectively reduce the material cost.

3. The polyimide material used in the polyimide-metal single-atom composite material prepared by the present invention has good chemical/electrochemical corrosion resistance, thermal stability and mechanical properties, and its surface contains nitrogen and oxygen. group that can be used to anchor metal single atoms.

Description of drawings

FIG. 1 is a spherical aberration electron microscope image of the polyimide-metal single-atom composite material in Example 1. FIG.

FIG. 2 is an infrared spectrogram of the polyimide-metal single-atom composite material in Example 1. FIG.

FIG. 3 is an X-ray photoelectron spectrum diagram of the polyimide-metal single-atom composite material of Example 1. FIG. Figure a is the high-resolution spectrum of nitrogen, and Figure b is the high-resolution spectrum of platinum.

FIG. 4 is an X-ray absorption spectrum of the polyimide-metal single-atom composite material of Example 1. FIG. Figure a is the X-ray near-edge absorption spectrum, and Figure b is the X-ray extended-edge absorption spectrum.

FIG. 5 is a linear sweep voltammogram of the polyimide-metal single-atom composite material of Example 1. FIG.

FIG. 6 is a chronopotentiometry analysis diagram of the polyimide-metal single-atom composite material in Example 1. FIG.

FIG. 7 is a bar graph showing the comparison of the metal loading content of the polyimide-metal single-atom composite material in Example 1. FIG.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Unless otherwise specified, the sources of reagents used in the examples of the present invention can be purchased through commercially available methods.

The present invention provides the accompanying drawings of the characterization test results of Example 1. The other embodiments all adopt the same characterization test method. Those skilled in the art can directly and without doubt determine the embodiments of the present invention through the characterization test method provided by the present invention. Content.

Example 1: Preparation of polyimide-platinum single-atom composites

(1) Using a balance, weigh 4.00g (0.02mol) of 4,4'-diaminodiphenyl ether into a three-necked flask, and then add 47.38g of N,N-dimethylformamide. At the same time, the stirring motor was turned on for stirring and the nitrogen gas was kept flowing, so that the reaction system was in a nitrogen atmosphere. After complete dissolution, 4.36 g (0.02 mol) of pyromellitic dianhydride was added in four batches. Continue stirring in an ice-water bath or at room temperature until a pale yellow viscous polyamic acid solution is obtained.

(2) Weigh 1.00g of polyamic acid solution into a blue bottle, add 10.00g of N,N-dimethylformamide, control the solid content to 10%, and use magnetic stirring to completely dilute the polyamic acid solution. And cut out 0.5 × 1.0 cm ² of carbon paper as a carrier.

(3) Take 10 μL of the mixed solution obtained in step (2) and drop them on the front and back sides of the carbon paper respectively. Use a tube furnace or muffle furnace for step heating of the obtained carbon paper. The temperature nodes are: 70°C, 100°C, 150°C, 200°C, 300°C, and 350°C, and the heating rate is 5°C min ^-1 . Each temperature node was kept for 1 h to complete the preparation of the polyimide/carbon paper composite substrate.

(4) The polyimide/carbon paper composite material obtained in the step (3) is placed in the reaction chamber of the atomic layer deposition equipment, the source bottle is adjusted to be the platinum salt precursor, and the temperature of the reaction chamber is set to 300°C, The source bottle temperature was 65° C., the source line flow was 150 sccm, the oxygen line flow was 50 sccm, the hydrogen line flow was 0 sccm, and the number of depositions was 25 cycles. The final product obtained is the polyimide-platinum single-atom composite material.

Example 2: Preparation of polyimide-ruthenium single-atom composites

(1) Using a balance, weigh 4.00g (0.02mol) of 4,4'-diaminodiphenyl ether into a three-necked flask, and then add 47.38g of N,N-dimethylformamide. At the same time, the stirring motor was turned on for stirring and the nitrogen gas was kept flowing, so that the reaction system was in a nitrogen atmosphere. After complete dissolution, 4.36 g (0.02 mol) of pyromellitic dianhydride was added in four batches. Continue stirring in an ice-water bath or at room temperature until a pale yellow viscous polyamic acid solution is obtained.

(2) Weigh 1.00g of polyamic acid solution in a blue bottle, add 10.00g of N,N-dimethylformamide, control the solid content to be 10%, and use magnetic stirring to completely dilute the polyamic acid solution, And cut out 0.5 × 1.0 cm ² of carbon paper as a carrier.

(3) Take 10 μL of the mixed solution obtained in step (2) and drop them on the front and back sides of the carbon paper respectively. Use a tube furnace or muffle furnace for step heating of the obtained carbon paper. The temperature nodes are: 70°C, 100°C, 150°C, 200°C, 300°C, and 350°C, and the heating rate is 5°C min ^-1 . Each temperature node was kept for 1 h to complete the preparation of the polyimide/carbon paper composite substrate.

(4) The polyimide/carbon paper composite material obtained in the step (3) is placed in the reaction chamber of the atomic layer deposition equipment, the source bottle is replaced with a ruthenium salt precursor, and the temperature of the reaction chamber is set to 350°C, The source bottle temperature was 85° C., the source line flow was 120 sccm, the oxygen line flow was 80 sccm, the hydrogen line flow was 0 sccm, and the number of depositions was 100 cycles. The final product obtained is a polyimide-ruthenium single-atom composite material.

Example 3: Preparation of polyimide-platinum single-atom composites

(1) Using a balance, weigh 2.16 g (0.02 mol) of p-phenylenediamine into a three-necked flask, and then add 47.38 g of N,N-dimethylformamide. At the same time, the stirring motor was turned on for stirring and the nitrogen gas was kept flowing, so that the reaction system was in a nitrogen atmosphere. After complete dissolution, 4.36 g (0.02 mol) of p-phenylene ether dianhydride was added in four batches. Continue stirring in an ice-water bath or at room temperature until a pale yellow viscous polyamic acid solution is obtained.

(2) Weigh 1.00g of polyamic acid solution into a blue bottle, add 10.00g of N,N-dimethylformamide, control the solid content to 10%, and use magnetic stirring to completely dilute the polyamic acid solution. And cut out 0.5 × 1.0 cm ² of carbon paper as a carrier.

(3) Take 10 μL of the mixed solution obtained in step (2) and drop them on the front and back sides of the carbon paper respectively. Use a tube furnace or muffle furnace for step heating of the obtained carbon paper. The temperature nodes are: 70°C, 100°C, 150°C, 200°C, 300°C, and 350°C, and the heating rate is 5°C min ^-1 . Each temperature node was kept for 1 h to complete the preparation of the polyimide/carbon paper composite substrate.

(4) The polyimide/carbon paper composite material obtained in the step (3) is placed in the reaction chamber of the atomic layer deposition equipment, the source bottle is adjusted to be the platinum salt precursor, and the temperature of the reaction chamber is set to 300°C, The source bottle temperature was 65° C., the source line flow was 150 sccm, the oxygen line flow was 50 sccm, the hydrogen line flow was 0 sccm, and the number of depositions was 25 cycles. The final product obtained is the polyimide-platinum single-atom composite material.

Example 4: Preparation of polyimide-platinum single-atom composites

(1) Using a balance, weigh 4.00g (0.02mol) of 4,4'-diaminodiphenyl ether into a three-necked flask, and then add 47.38g of N,N-dimethylformamide. At the same time, the stirring motor was turned on for stirring and the nitrogen gas was kept flowing, so that the reaction system was in a nitrogen atmosphere. After complete dissolution, 4.36 g (0.02 mol) of pyromellitic dianhydride was added in four batches. Continue stirring in an ice-water bath or at room temperature until a pale yellow viscous polyamic acid solution is obtained.

(2) Weigh 1.00g of polyamic acid solution into a blue bottle, add 10.00g of N,N-dimethylformamide, control the solid content to 10%, and use magnetic stirring to completely dilute the polyamic acid solution. And cut out 0.5 × 1.0 cm ² of carbon paper as a carrier.

(3) Take 10 μL of the mixed solution obtained in step (2) and drop them on the front and back sides of the carbon paper respectively. Use a tube furnace or muffle furnace for step heating of the obtained carbon paper. The temperature nodes are: 70°C, 100°C, 150°C, 200°C, 300°C, and 350°C, and the heating rate is 5°C min ^-1 . Each temperature node was kept for 1 h to complete the preparation of the polyimide/carbon paper composite substrate.

(4) The polyimide/carbon paper composite material obtained in the step (3) is placed in the reaction chamber of the atomic layer deposition equipment, the source bottle is adjusted to be the platinum salt precursor, and the temperature of the reaction chamber is set to 350°C, The source bottle temperature was 65°C, the source line flow was 150 sccm, the oxygen line flow was 80 sccm, the hydrogen line flow was 0 sccm, and the number of depositions was 50 cycles. The final product obtained is the polyimide-platinum single-atom composite material.

Performance test of the polyimide-platinum single-atom composite material obtained in the embodiment

Figure 1 shows the spherical aberration electron microscope image of the polyimide-platinum single-atom composite material in Example 1, and it can be seen that the platinum single-atom is dispersed on the surface of the polyimide material.

As shown in FIG. 2 , the infrared spectrum of the polyimide-platinum single-atom composite material in Example 1 is shown, and the typical infrared characteristic peaks of polyimide can be seen.

As shown in FIG. 3 , the X-ray photoelectron spectrum of the polyimide-platinum single-atom composite material in Example 1 shows that the polyimide-platinum single-atom composite material contains nitrogen and platinum elements.

Figure 4 shows the X-ray absorption spectrum of the polyimide-platinum single-atom composite material in Example 1, and obvious platinum-oxygen peaks can be seen, and no platinum-platinum peaks are observed, confirming that the prepared polyamide The metal components in the imine-platinum single-atom composite material are all single atoms.

Figure 5 shows the linear sweep voltammetry curve of the polyimide-platinum single-atom composite material in Example 1. It can be seen from the figure that the prepared polyimide-platinum single-atom composite material is in 0.5MH ₂ SO ₄ shows excellent electrochemical hydrogen evolution performance in the electrolyte, and the overpotential of the material is as low as 22mV under the current density of 10mA cm ^-2 , and the current density of 200mA cm ^-2 can be reached at the overpotential of 0.5V.

Fig. 6 is the chronopotentiometry analysis diagram of the polyimide-metal single-atom composite material in Example 1. It can be seen from the figure that the prepared polyimide-platinum single-atom composite material shows the performance under the current density of 10mA cm ^-2 It exhibits good electrochemical stability, running stably for 1200h in 0.5MH ₂ SO ₄ electrolyte, and the potential decay is only within 20mV.

Figure 7 is a bar chart showing the comparison of the metal loading content of the polyimide-metal single-atom composite materials of Examples 1 and 4. It can be seen from the figure that the number of deposition cycles in the prepared polyimide-platinum single-atom composite materials varies from The metal single-atom loading under 5-40 cycles is 0.015wt%-0.500wt%, and the loading is positively correlated with the number of deposition cycles, indicating that the more deposition cycles, the higher the metal single-atom loading, so it can be considered that, The loading content of the metal can be further increased by continuing to increase the number of turns.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention.

Claims (12)

1. The preparation method of the polyimide-metal monoatomic composite material is characterized by comprising the following steps of:

(i) coating a polyamic acid solution on a carrier material, putting the carrier material into a tubular furnace or a muffle furnace, and carrying out step heating to prepare a polyimide/carrier composite material;

(ii) and loading metal monoatomic atoms on the polyimide/carrier composite material by an atomic layer deposition method to obtain the polyimide-metal monoatomic composite material loaded on the carrier material.

2. The method for preparing a polyimide-metal monatomic composite material according to claim 1, wherein the method for preparing the polyamic acid solution comprises: dissolving diamine monomer in reaction solvent, introducing nitrogen, and adding dianhydride monomer under the condition of ice water bath or normal temperature stirring to prepare the polyamic acid solution.

3. The method of claim 2, wherein the molar ratio of diamine monomer to dianhydride monomer is 1.0: 1.0 to 1.0: 1.1.

4. The method for preparing a polyimide-metal monatomic composite material according to claim 2, wherein the diamine monomer comprises one or more of p-phenylenediamine, benzidine, diaminodiphenyl ether, or diaminobenzophenone;

the dianhydride monomer comprises one or more of pyromellitic dianhydride, hexafluoro dianhydride, pyromellitic dianhydride or benzophenone tetracarboxylic dianhydride;

the reaction solvent comprises one or more than one of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

5. The method for preparing a polyimide-metal monatomic composite material according to claim 1, wherein the mass concentration of the polyamic acid solution in the step (i) is 3% to 15%, and the solvent of the polyamic acid solution includes one or more of N, N-dimethylformamide, N-dimethylacetamide, or N-methylpyrrolidone.

6. The method for preparing polyimide-metal monatomic composite material according to claim 1, wherein the dropping amount of the polyamic acid solution in the step (i) is 10 to 40 μ Lcm ^-2 The carrier material comprises any one of carbon paper, carbon aerogel, carbon felt and carbon fiber.

7. The method for preparing the polyimide-metal monatomic composite material according to claim 1, wherein the temperature nodes of the stepwise temperature increase in the step (i) are sequentially: heating at 70 deg.C, 100 deg.C, 200 deg.C, 300 deg.C, 350 deg.C and 2-5 deg.C for min ^-1 And keeping the temperature of each temperature point for 50-60 min.

8. The method according to claim 1, wherein the metal species in the deposition process of the primary layer in step (ii) comprises any one of platinum, ruthenium, iridium, iron, cobalt, copper and molybdenum.

9. The method for preparing polyimide-metal monatomic composite material according to claim 1, wherein in the original layer deposition method in the step (ii), the process parameters are as follows: the temperature of the reaction chamber is 280-350 ℃, the temperature of the source bottle is 70-85 ℃, the flow rate of the source line is 120-150sccm, the flow rate of the oxygen line is 50-80sccm, the flow rate of the hydrogen line is 0-120sccm, and the deposition times are 25-200 circles.

10. A polyimide-metal monoatomic composite material, characterized by being produced by the production method according to any one of claims 1 to 9.

11. The polyimide-metal monatomic composite material of claim 10, wherein the surface of the polyimide-metal monatomic composite material has metal monatomic content of not less than 0.015 wt%.

12. The use of the polyimide-metal monatomic composite material according to any one of claims 1 to 9 or the use of the polyimide-metal monatomic composite material according to claim 10 or 11, including applications in the fields of catalysis, heat conduction, dielectric energy storage, electromagnetic wave shielding and wave absorption, and electrochemical energy storage.

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