A preparation method of polymeric nitrogen and polymeric nitrogen

Abstract

The present invention discloses a method for preparing polymerized nitrogen and polymerized nitrogen, belonging to the technical field of energetic materials, and solves one of the following problems: (1) the relatively harsh conditions for synthesizing cg-PN; and (2) the low content of cg-PN prepared by existing techniques. The preparation method of the present invention obtains polymerized nitrogen by quenching an azide compound and carbon nanotubes from a high temperature to room temperature under high pressure. The cg-PN prepared by the preparation method of the present invention has a high yield and can be recovered under conventional conditions, and has potential application value in the field of energetic materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of energetic materials, and in particular relates to a preparation method of polymerized nitrogen and polymerized nitrogen. Background Art

[0002] The average bond energy of the nitrogen-nitrogen triple bond (N≡N) in nitrogen molecules (N≡N) is as high as 946 kJ / mol, demonstrating extremely high chemical stability and being widely considered one of the most stable diatomic molecules in nature. The average bond energy of a nitrogen-nitrogen double bond (N=N) is 419 kJ / mol, while the average bond energy of a nitrogen-nitrogen single bond (N–N) is only 159 kJ / mol. When nitrogen molecules (N≡N) are converted to nitrogen-nitrogen single bonds (N–N), a polymeric nitrogen material is formed, a process that stores significant energy. Conversely, when these all-nitrogen compounds decompose under suitable conditions, the polymeric nitrogen bound by nitrogen single bonds can be converted into stable nitrogen-nitrogen triple bonds (N≡N), releasing approximately 800 kJ / mol of energy. Therefore, all-nitrogen compounds consisting solely of nitrogen single bonds theoretically possess extremely high energy storage and release capabilities and are widely considered to be high-energy-density materials with potential applications.

[0003] Currently, the synthesis of polymerized nitrogen typically requires extreme conditions such as high temperature and pressure. In 2004, Eremets et al. reported the successful synthesis of cg-PN using molecular nitrogen as a precursor at a pressure of approximately 110 GPa and a temperature of 2000 K. Unfortunately, cg-PN is not stable at ambient pressure. Summary of the Invention

[0004] In view of the above analysis, the present invention aims to provide a method for preparing polymerized nitrogen and polymerized nitrogen to solve one of the following technical problems: (1) the conditions for synthesizing polymerized nitrogen (i.e., cg-PN) are relatively harsh; (2) the cg-PN prepared by the existing technology has a low content.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a method for preparing polymerized nitrogen, wherein the polymerized nitrogen is obtained by quenching an azide compound and carbon nanotubes from a high temperature to room temperature under high pressure.

[0007] Furthermore, the azide compound includes one or more of KN3, NaN3, LiN3 and NH4N3.

[0008] Furthermore, the carbon nanotubes include one or more of single-walled carbon nanotubes, carboxylated single-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, amino-modified multi-walled carbon nanotubes, graphitized multi-walled carbon nanotubes, graphitized carboxylated multi-walled carbon nanotubes, carbon nanotube films, and highly conductive carbon nanotube films.

[0009] Furthermore, the pressure range of high pressure is 1GPa to 30GPa.

[0010] Furthermore, the high temperature range is 100°C to 500°C.

[0011] Furthermore, the mass ratio of the azide compound to the carbon nanotubes is 1:0.2-0.5.

[0012] Furthermore, the preparation method further comprises: quenching to room temperature and then releasing the pressure to obtain polymerized nitrogen.

[0013] Furthermore, the pressure relief rate is 0.5 GPa / min to 1 GPa / min.

[0014] Furthermore, the cooling time of quenching is controlled within 1 min.

[0015] The present invention also provides polymeric nitrogen, which is prepared by the above preparation method.

[0016] Compared with the prior art, the present invention can achieve at least one of the following technical effects:

[0017] 1) In the preparation method of the present invention, azide compound and carbon nanotubes are mixed and then quenched from high temperature to room temperature under high pressure to obtain polymerized nitrogen. By providing the degree of freedom of pressure, the carbon nanotubes are combined to make N3 - The nitrogen-nitrogen double bond in the nitrogen is dissociated to form a nitrogen-nitrogen single bond material to obtain polymerized nitrogen. The preparation method of the present invention reduces the preparation conditions of polymerized nitrogen from 110GPa to 1GPa-30GPa, greatly reducing the difficulty of synthesis.

[0018] 2) The preparation method of the present invention produces a higher cg-PN content. For example, in the Raman spectrum, the Raman peak corresponding to the A mode of cg-PN is 0.7 to 4 times the characteristic peak of the raw material. Furthermore, the cg-PN material prepared by this method is not limited to maintaining its stability under high-pressure conditions. Even after the high pressure applied during the synthesis process is released, the cg-PN can still maintain its structure and performance under normal pressure, breaking through the limitation of traditional technologies that polymerized nitrogen can only exist under extreme high pressure. This feature makes the material more operational and flexible in practical applications, and can open up new application prospects in fields such as energy storage and high-energy-density energetic materials.

[0019] 3) The method of the present invention achieves a fast cg-PN synthesis reaction rate, which can improve synthesis efficiency. The method of the present invention has good operability and industrial application prospects, and is expected to bring new breakthroughs in the preparation of high-energy-density energetic materials and provide important technical support for the research and development of energy materials.

[0020] Other features and advantages of the present invention will be described in the following description, and in part they may become apparent from the description or may be understood through implementation of the present invention. The purposes and other advantages of the present invention may be realized and obtained through the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings are only for purposes of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference numerals designate like components throughout the drawings.

[0022] Figure 1 is the Raman spectrum of cg-PN of Example 1 of the present invention;

[0023] Figure 2 is the Raman spectrum of cg-PN of Example 2 of the present invention;

[0024] Figure 3 is the Raman spectrum of cg-PN of Example 3 of the present invention;

[0025] Figure 4 is the Raman spectrum of the unknown phase of Comparative Example 1 of the present invention;

[0026] Figure 5 is the Raman spectrum of the unknown phase of Comparative Example 2 of the present invention;

[0027] Figure 6 is the Raman spectrum of cg-PN of Example 1-1 of the present invention;

[0028] Figure 7 This is the Raman spectrum of Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0029] The following is a further detailed description of a preparation method of polymerized nitrogen and polymerized nitrogen in conjunction with specific examples. These examples are only for comparison and explanation purposes, and the present invention is not limited to these examples.

[0030] The present invention provides a method for preparing polymerized nitrogen. The method comprises quenching an azide compound and a carbon nanotube (hereinafter referred to as CNT) from a high temperature to room temperature under high pressure to obtain polymerized nitrogen.

[0031] Specifically, the above-mentioned azide compound includes one or more of KN3, NaN3, LiN3 and NH4N3.

[0032] Specifically, the above-mentioned carbon nanotubes include one or more of single-walled carbon nanotubes, carboxylated single-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, amino-modified multi-walled carbon nanotubes, graphitized multi-walled carbon nanotubes, graphitized carboxylated multi-walled carbon nanotubes, carbon nanotube films, and highly conductive carbon nanotube films.

[0033] Specifically, the pressure range of the above-mentioned high pressure is 1GPa~30GPa. For example, the pressure of the high pressure is 1GPa, 2GPa, 3GPa, 4GPa, 5GPa, 6GPa, 7GPa, 8GPa, 9GPa, 10GPa, 11GPa, 12GPa, 13GPa, 14GPa, 15GPa, 16GPa, 17GPa, 18GPa, 19GPa, 20GPa, 21GPa, 22GPa, 23GPa, 24GPa, 25GPa, 26GPa, 27GPa, 28GPa, 29GPa, and 30GPa.

[0034] Specifically, the high temperature range is 100°C to 500°C, for example, 200°C, 300°C, 400°C, or 500°C.

[0035] Specifically, considering that too much carbon nanotubes will result in a low relative content of cg-PN in the product, hindering its full detonation performance, while too little will reduce the conversion rate of cg-PN, hindering the increase in cg-PN production, the mass ratio of the azide compound to carbon nanotubes is controlled to be between 1:0.1 and 0.5, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, and 1:0.5.

[0036] Specifically, when the azide compound is NaN3, the high pressure is 1 to 8 GPa, for example, 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa; the high temperature is 150 to 300°C, for example, 170°C, 190°C, 210°C, 230°C, 250°C, 270°C.

[0037] Specifically, when the azide compound is KN3, the high pressure is 2 to 10 GPa, for example, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa, and 9 GPa; the high temperature is 250 to 500°C, for example, 270°C, 290°C, 310°C, 330°C, 350°C, 370°C, 390°C, 410°C, 430°C, 450°C, and 470°C.

[0038] Specifically, when the azide compound is LiN3, the high pressure is 1 to 8 GPa, for example, 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa; the high temperature is 100 to 200°C, for example, 110°C, 130°C, 150°C, 170°C.

[0039] Specifically, when the azide compound is NH4N3, the high pressure is 1 to 8 GPa, for example, 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa; the high temperature is 80 to 200°C, for example, 100°C, 130°C, 150°C, 170°C.

[0040] Specifically, the preparation method of the polymerized nitrogen comprises the following steps:

[0041] S1. Azide compound and carbon nanotube (CNT) raw materials are uniformly mixed in proportion, encapsulated in an inert metal cylinder, and then placed in a high-pressure chamber;

[0042] S2. Pressurize the mixed raw materials. After reaching the target pressure, start heating and maintain the pressure and temperature.

[0043] S3. Quenching treatment under high pressure conditions: the temperature at the sample location is quickly lowered to room temperature, and polymerized nitrogen (cg-PN) is obtained after pressure relief.

[0044] It should be noted that in S1, the material of the inert metal cylinder is tantalum, stainless steel, gold, platinum, etc. The material of the inert metal cylinder does not react with the raw material and can prevent N3 - It escapes in the form of N2 without participating in the reaction.

[0045] It should be noted that, in S1, the corresponding high-pressure equipment is selected according to the combined pressure, and the high-pressure equipment can be a six-sided top press or a two-stage propulsion press.

[0046] It should be noted that in S1, in order to prevent the azide compound from absorbing water, the azide compound and the carbon nanotube raw material were uniformly mixed in a glove box, ground and mixed in a mortar for 30 minutes, and then directly placed in an inert metal cylinder.

[0047] It should be noted that, in S1, the diameter of the inert metal cylinder is 6 to 30 mm and the thickness is 0.5 mm. The size of the inert metal cylinder is mainly determined by the target sample amount to be prepared.

[0048] It should be noted that in S2, the target pressure range required for the synthesis of polymerized nitrogen (cg-PN) materials in the high-pressure chamber is 1 GPa to 30 GPa, such as 1 GPa, 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa, 9 GPa, 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, 16 GPa, 17 GPa, 18 GPa, 19 GPa, 20 GPa, 21 GPa, 22GPa, 23GPa, 24GPa, 25GPa, 26GPa, 27GPa, 28GPa, 29GPa, 30GPa; the target temperature range is 100℃~500℃, for example, 200℃, 300℃, 400℃, 500℃; the holding time is 20min~120min, for example, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min.

[0049] It should be noted that, in S3, the cooling time of the quenching treatment is generally controlled within 1 minute.

[0050] Specifically, in S3, the cooling rate of the quenching treatment is 100-150°C / s, for example, 110°C / s, 120°C / s, or 130°C / s.

[0051] It should be noted that in S3, the pressure relief rate is 0.5 GPa / min to 1 GPa / min, for example, 0.6 GPa / min, 0.7 GPa / min, 0.8 GPa / min, and 0.9 GPa / min.

[0052] Specifically, before S1, the preparation work for high-voltage assembly is completed, including the following steps:

[0053] S01. Select the corresponding high-pressure equipment according to the synthetic pressure of the target material;

[0054] S02. According to the type of high-voltage equipment, select the corresponding high-voltage assembly, including pressure transmission medium, sample chamber, heating component, inert metal cylinder, thermocouple, etc.

[0055] The present invention also provides polymeric nitrogen, which is prepared by the above preparation method.

[0056] Specifically, the polymerized nitrogen (cg-PN) of the present invention is a three-dimensional network of polymerized nitrogen structures formed by covalent N-N single bonds. This cg-PN material has a unique chemical bonding method, which gives it a structurally high energy storage capacity.

[0057] Specifically, the polymerized nitrogen material prepared by the method of the present invention reduces the kinetic instability of the polymerized nitrogen material due to the hybridization of carbon nanotubes and polymerized nitrogen, and can maintain its structure and performance under normal pressure environment, breaking through the limitation of traditional technology that polymerized nitrogen can only exist under extremely high pressure.

[0058] Specifically, the polymeric nitrogen material prepared by the preparation method of the present invention is a very ideal high-energy density material with a wide range of potential applications, especially in high-energy storage and high-efficiency fuel.

[0059] The embodiments and comparative examples of the present invention use a ReniShaw Raman spectrometer to perform Raman spectroscopy measurements, with a laser wavelength of 532 nm, a grating of 2400 l / mm, a power output of 0.5% to 5% (for example, 0.5%, 1%, or 5%), an integration time of 10 to 120 s (for example, 10 s, 30 s, 60, or 120 s), an integration number of 1 to 4 times (for example, 1 time, 2 times, 3 times, or 4 times), and a Raman spectrum test range of 100 to 1500 cm-1.

[0060] The preparation method of the present invention can produce a high content of cg-PN. For example, in the Raman spectrum, the intensity of the Raman peak corresponding to the A mode of cg-PN is greater than 400, for example, 420 to 2000, which is 0.7 to 4 times that of the characteristic peak of the raw material. This preparation method not only significantly improves the production efficiency of cg-PN, but also ensures that the prepared cg-PN material can maintain its structural stability under normal pressure. The method of the present invention has good operability and industrial application prospects, and is expected to bring new breakthroughs in the field of high-energy material preparation and provide important technical support for the research and development of energy materials.

[0061] The embodiments and comparative examples of the present invention use a ReniShaw Raman spectrometer to perform Raman spectrum measurement, with a laser wavelength of 532 nm, a grating of 2400 l / mm, a power output of 0.5% to 5% (for example, 0.5%, 1% or 5%), an integration time of 10 to 120 s (for example, 10 s, 30 s, 60 or 120 s), an integration number of 1 to 4 times (for example, 1 time, 2 times, 3 times or 4 times), and a Raman spectrum test range of 100 to 1500 cm -1 .

[0062] Example 1

[0063] This embodiment provides a method for preparing polymerized nitrogen, comprising the following steps:

[0064] S1. uniformly mixing azide compound and carbon nanotube (CNT) raw materials in a certain proportion, encapsulating them in an inert metal cylinder, and then placing them in a high-pressure chamber;

[0065] S2. Pressurizing the azide compound and carbon nanotube (CNT) raw materials. After reaching the target pressure, heating is started and the pressure and temperature are maintained;

[0066] S3. Perform quenching treatment under high pressure conditions to quickly reduce the temperature of the sample to room temperature, and obtain cg-PN after pressure relief.

[0067] Specifically, in S1, the azide compound is KN3.

[0068] Specifically, in S1, the carbon nanotubes are amino-modified multi-walled carbon nanotubes.

[0069] Specifically, in S1, the mass ratio of KN3 to amino-modified multi-walled carbon nanotubes is 1:0.4.

[0070] Specifically, the material of the inert metal cylinder is gold, which does not react with the raw material and can prevent N3 - It escapes in the form of N2 without participating in the reaction.

[0071] Specifically, before S1, the preparation work for high-voltage assembly is completed, including the following steps:

[0072] S01 select the corresponding high-pressure equipment six-sided top press according to the synthetic pressure of the target material;

[0073] S02. According to the type of high-voltage equipment, select the corresponding high-voltage assembly, including pressure transmission medium, sample chamber, heating component, inert metal cylinder, thermocouple, etc.

[0074] Specifically, in S1, to prevent KN3 from absorbing water, KN3 and amino-modified multi-walled carbon nanotubes were mixed in a glove box, ground and mixed in a mortar for 30 minutes, and then directly placed in an inert metal cylinder.

[0075] Specifically, in S1, the inert metal cylinder has a diameter of 6 mm and a thickness of 0.5 mm.

[0076] Specifically, in S2, when pressurizing, the six top hammers (upper, lower, left, right, front and rear) synchronously squeeze the cubic sample assembly block under the push of oil pressure, thereby generating high pressure in the sample cavity.

[0077] Specifically, in S2, the target pressure is 5 GPa.

[0078] Specifically, in S2, the target temperature is 400°C and the holding time is 60 minutes.

[0079] Specifically, the quenching treatment in S3 has a cooling rate of 150°C / s, and rapid cooling is achieved by controlling the cooling water temperature.

[0080] Specifically, in S3, the pressure relief rate is 0.6 GPa / min.

[0081] The Raman spectrum of the polymerized nitrogen (cg-PN) prepared in this example is as follows: Figure 1 As shown in the Raman spectrum, at 142 cm -1 、634cm -1 、1268cm -1 and 1340cm -1 There are four obvious strong peaks at 142cm -1 、1268cm -1 and 1340cm -1 Corresponding to N3 - , 634cm -1 The Raman peak corresponding to the A mode of cg-PN has an intensity of 1393, which is about 4 times that of the characteristic peak of the raw material KN3.

[0082] Example 1-1

[0083] This embodiment provides a method for preparing polymerized nitrogen. The overall steps are the same as those in Example 1, except that:

[0084] In step S1, the ratio of KN3 to amino-modified multi-walled carbon nanotubes is 1:0.1.

[0085] In step S2, the target temperature is 400°C and the heating time is 30 minutes.

[0086] The Raman spectrum of the synthetic material of this embodiment is shown in FIG. Figure 6 As shown, the Raman spectrum in this embodiment is at 632 cm -1 There is a small peak with an intensity of 429, which is about 0.7 times the characteristic peak of raw material KN3, and is a small amount of cg-PN. This shows that the effect is slightly worse when the ratio of KN3 to amino-treated multi-walled carbon nanotubes is 1:0.1.

[0087] Example 2

[0088] This embodiment provides a method for preparing polymerized nitrogen, comprising the following steps:

[0089] S1. uniformly mixing azide compound and carbon nanotube (CNT) raw materials in a certain proportion, encapsulating them in an inert metal cylinder, and then placing them in a high-pressure chamber;

[0090] S2. Pressurizing the azide compound and carbon nanotube (CNT) raw materials. After reaching the target pressure, heating is started and the pressure and temperature are maintained;

[0091] S3. Perform quenching treatment under high pressure conditions to quickly reduce the temperature of the sample to room temperature, and obtain cg-PN after pressure relief.

[0092] Specifically, in S1, the azide compound raw material is NaN3.

[0093] Specifically, in S1, the carbon nanotubes (CNTs) are amino-modified multi-walled carbon nanotubes.

[0094] Specifically, in S1, the ratio of NaN3 to amino-modified multi-walled carbon nanotubes is 1:0.4.

[0095] Specifically, the inert metal cylinder is made of gold.

[0096] Specifically, before S1, the preparation work for high-voltage assembly is completed, including the following steps:

[0097] S01 select the corresponding high-pressure equipment six-sided top press according to the synthetic pressure of the target material;

[0098] S02. According to the type of high-voltage equipment, select the corresponding high-voltage assembly, including pressure transmission medium, sample chamber, heating component, inert metal cylinder, thermocouple, etc.

[0099] Specifically, in S1, in order to prevent NaN3 from absorbing water, NaN3 and amino-modified multi-walled carbon nanotubes were uniformly mixed in a glove box, ground and mixed in a mortar for 30 minutes, and then directly placed in an inert metal cylinder.

[0100] Specifically, in S1, the inert metal cylinder has a diameter of 6 mm and a thickness of 0.5 mm.

[0101] Specifically, in S2, when pressurizing, the six top hammers (upper, lower, left, right, front and rear) synchronously squeeze the cubic sample assembly block under the push of oil pressure, thereby generating high pressure in the sample cavity.

[0102] Specifically, in S2, the target pressure is 3 GPa.

[0103] Specifically, in S2, the target temperature is 250°C and the holding time is 60 minutes.

[0104] Specifically, in S3, the cooling rate of the quenching treatment is 150°C / s, and rapid cooling is achieved by controlling the cooling water temperature.

[0105] Specifically, in S3, the pressure relief rate is 0.6 GPa / min.

[0106] The Raman spectrum of the polymerized nitrogen (cg-PN) prepared in this example is as follows: Figure 2 As shown, in the Raman spectrum of this embodiment, N3 - At 147cm -1 、1268cm -1 and 1340m-1 There are three obvious strong peaks at 634cm -1 The Raman peak corresponding to the A mode of cg-PN has an intensity of 839, which is about 1 times that of the characteristic peak of the raw material NaN3.

[0107] Example 3

[0108] This embodiment provides a method for preparing polymerized nitrogen (cg-PN), comprising the following steps:

[0109] S1. uniformly mixing azide compound and carbon nanotube (CNT) raw materials in a certain proportion, encapsulating them in an inert metal cylinder, and then placing them in a high-pressure chamber;

[0110] S2. Pressurizing the azide compound and carbon nanotube (CNT) raw materials. After reaching the target pressure, heating is started and the pressure and temperature are maintained;

[0111] S3. Perform quenching treatment under high pressure conditions to quickly reduce the temperature of the sample to room temperature, and obtain cg-PN after pressure relief.

[0112] Specifically, in S1, the azide compound raw material is LiN3.

[0113] Specifically, in S1, the carbon nanotubes (CNTs) are amino-modified multi-walled carbon nanotubes.

[0114] Specifically, in S1, the ratio of LiN3 to amino-modified multi-walled carbon nanotubes is 1:0.3.

[0115] Specifically, the inert metal cylinder is made of gold, which does not react with the raw material and can prevent N3 - It escapes in the form of N2 without participating in the reaction.

[0116] Specifically, before S1, the preparation work for high-voltage assembly is completed, including the following:

[0117] S01 select the corresponding high-pressure equipment six-sided top press according to the synthetic pressure of the target material;

[0118] S02. According to the type of high-voltage equipment, select the corresponding high-voltage assembly, including pressure transmission medium, sample chamber, heating component, inert metal cylinder, thermocouple, etc.

[0119] Specifically, in S1, to prevent LiN3 from absorbing water, LiN3 and amino-modified multi-walled carbon nanotubes were uniformly mixed in a glove box, ground and mixed in a mortar for 30 minutes, and then directly placed in an inert metal cylinder.

[0120] Specifically, in S1, the inert metal cylinder has a diameter of 6 mm and a thickness of 0.5 mm.

[0121] Specifically, in S2, when pressurizing, the six top hammers (upper, lower, left, right, front and rear) synchronously squeeze the cubic sample assembly block under the push of oil pressure, thereby generating high pressure in the sample cavity.

[0122] Specifically, in S2, the target pressure is 5 GPa.

[0123] Specifically, in S2, the target temperature is 120°C and the holding time is 120 minutes.

[0124] Specifically, in S3, the cooling rate of the quenching treatment is 150°C / s, and rapid cooling is achieved by controlling the cooling water temperature.

[0125] Specifically, in S3, the pressure relief rate is 0.6 GPa / min.

[0126] The Raman spectrum of the polymerized nitrogen (cg-PN) prepared in this example is as follows: Figure 3 As shown, in the Raman spectrum of LiN3 in this embodiment, N3 - 145cm respectively -1 、1267cm -1 and 1340cm -1 There are three obvious strong peaks at 632cm -1 The Raman peak corresponding to the A mode of cg-PN has an intensity of 1952, which is about twice the characteristic peak of the raw material LiN3.

[0127] Example 4

[0128] This embodiment provides a method for preparing polymerized nitrogen, comprising the following steps:

[0129] S1. uniformly mixing azide compound and carbon nanotube (CNT) raw materials in a certain proportion, encapsulating them in an inert metal cylinder, and then placing them in a high-pressure chamber;

[0130] S2. Pressurizing the azide compound and carbon nanotube (CNT) raw materials. After reaching the target pressure, heating is started and the pressure and temperature are maintained;

[0131] S3. Perform quenching treatment under high pressure conditions to quickly reduce the temperature of the sample to room temperature, and obtain cg-PN after pressure relief.

[0132] Specifically, in S1, the azide compound raw material is KN3.

[0133] Specifically, in S1, the carbon nanotubes (CNTs) are carboxylated multi-walled carbon nanotubes.

[0134] Specifically, in S1, the ratio of KN3 to carboxylated multi-walled carbon nanotubes is 1:0.4.

[0135] Specifically, the inert metal cylinder is made of gold, which does not react with the raw material and can prevent N3 - It escapes in the form of N2 without participating in the reaction.

[0136] Specifically, before S1, the preparation work for high-voltage assembly is completed, including the following:

[0137] S01 select the corresponding high-pressure equipment six-sided top press according to the synthetic pressure of the target material;

[0138] S02. According to the type of high-voltage equipment, select the corresponding high-voltage assembly, including pressure transmission medium, sample chamber, heating component, inert metal cylinder, thermocouple, etc.

[0139] Specifically, in S1, to prevent KN3 from absorbing water, KN3 and carboxylated multi-walled carbon nanotubes were uniformly mixed in a glove box, ground and mixed in a mortar for 30 minutes, and then directly placed in an inert metal cylinder.

[0140] Specifically, in S1, the inert metal cylinder has a diameter of 6 mm and a thickness of 0.5 mm.

[0141] Specifically, in S2, when pressurizing, the six top hammers (upper, lower, left, right, front and rear) synchronously squeeze the cubic sample assembly block under the push of oil pressure, thereby generating high pressure in the sample cavity.

[0142] Specifically, in S2, the target pressure is 5 GPa.

[0143] Specifically, in S2, the target temperature is 400°C and the holding time is 120 minutes.

[0144] Specifically, in S3, the cooling rate of the quenching treatment is 150°C / s, and rapid cooling is achieved by controlling the cooling water temperature.

[0145] Specifically, in S3, the pressure relief rate is 0.6 GPa / min.

[0146] This example also carried out the same Raman spectrum test as in Example 1, and the results were basically the same. Due to limited space, they are not listed one by one.

[0147] Comparative Example 1

[0148] This comparative example provides a method for preparing a polymeric nitrogen material. The overall steps are the same as those in Example 1, except that:

[0149] In step S2, the target temperature is 600°C and the heating time is 30 minutes.

[0150] The Raman spectrum of the synthetic compound of this comparative example is as follows Figure 4 As shown, the Raman spectrum is at 634 cm -1There is no peak at , so cg-PN is not generated.

[0151] Comparative Example 2

[0152] This comparative example provides a method for preparing a polymerized nitrogen (cg-PN) material. The overall steps are the same as those in Example 1, except that:

[0153] In step S2, the target temperature is 800°C and the heating time is 30 minutes.

[0154] The Raman spectrum of the synthetic compound of this comparative example is as follows Figure 5 As shown, the Raman spectrum is at 634 cm -1 There is no peak at , so cg-PN is not generated.

[0155] Comparative Example 3

[0156] This comparative example provides a method for preparing a polymerized nitrogen (cg-PN) material. The overall steps are the same as those in Example 1, except that:

[0157] In S1, S element is added to the raw material of KN3+amino-modified multi-walled carbon nanotubes, and the ratio of KN3, amino-modified multi-walled carbon nanotubes and S element is 1:0.4:0.2.

[0158] The Raman spectrum of the synthetic compound of this comparative example is as follows Figure 7 As shown, the Raman spectrum in this comparative example is at 634 cm -1 There is no peak at , so cg-PN is not generated.

[0159] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing polymerized nitrogen, characterized in that: The preparation method comprises quenching an azide compound and carbon nanotubes from a high temperature to room temperature under high pressure, and then releasing the pressure to obtain polymerized nitrogen; The azide compound includes one or more of KN3, NaN3, LiN3 and NH4N3; The high pressure range is 1 GPa to 30 GPa; the high temperature range is 100° C. to 500° C.; The cooling time of quenching is controlled within 1 minute; the pressure relief rate is 0.5GPa / min~1GPa / min; The polymerized nitrogen is a three-dimensional network polymerized nitrogen structure formed by covalent N─N single bond connection.

2. The preparation method according to claim 1, characterized in that The carbon nanotubes include one or more of single-walled carbon nanotubes, carboxylated multi-walled carbon nanotubes, amino-treated multi-walled carbon nanotubes, graphitized multi-walled carbon nanotubes, and carbon nanotube films.

3. The preparation method according to claim 1, characterized in that The pressure range of the high pressure is 1GPa~29GPa.

4. The preparation method according to claim 1, characterized in that The high temperature range is 120°C to 500°C.

5. The preparation method according to any one of claims 1 to 4, characterized in that The mass ratio of the azide compound to the carbon nanotube is 1:0.1-0.

5.

6. The preparation method according to claim 1, characterized in that The pressure relief rate is 0.6GPa / min~1GPa / min.

7. The preparation method according to any one of claims 1 to 4, characterized in that The cooling rate of quenching is 100~150℃ / s.

8. A polymerized nitrogen, characterized in that The polymerized nitrogen is prepared by the preparation method according to any one of claims 1 to 7.

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