COFs (covalent organic frameworks) material containing monodisperse Cu sites, preparation method of COFs material and application of COFs material in thermal decomposition of ammonium perchlorate

Abstract

The invention relates to the technical field of composite materials, in particular to a COFs material containing monodisperse Cu sites, a preparation method of the COFs material and application of the COFs material in thermal decomposition of ammonium perchlorate. The COFs material containing the monodisperse Cu sites takes nitrogen-rich high-energy ligand carbohydrazide and trialdehyde phloroglucinol as reaction raw materials, the reaction raw materials are polymerized into a covalent organic framework precursor through an aldehyde-amine condensation reaction, and Tp-CBH-Cu-N (NO2) 2 is obtained through an impregnation reaction of the covalent organic framework precursor and a salt solution system of copper dinitramide. Monodisperse Cu sites in Tp-CBH-Cu-N (NO2) 2 serve as active sites, rapid and concentrated decomposition and heat release at the low temperature are achieved in the AP thermal decomposition catalysis process, the heat release temperature is 341.3 DEG C, the peak width is 9 DEG C, and the heat release temperature is far superior to the high decomposition temperature (the peak width is 30 DEG C) of 410.3 DEG C of AP and the multi-step decomposition process. In addition, the energetic anion dinitramide introduced into the COF skeleton improves the total heat release amount in the AP catalysis process.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a COFs material containing monodisperse Cu sites, a preparation method thereof, and an application thereof in thermal decomposition of ammonium perchlorate. Background Art

[0002] Solid rocket engines have many advantages such as unconstrained launch environment, advance loading, high working reliability, and high power. They are the source of flight power for tactical and strategic rocket weapons. Solid propellant, as the power provider, is a complex system composed of oxidizers, fuels, adhesives, plasticizers, antioxidants, bonding agents, etc. The decomposition and combustion characteristics of energy components represented by oxidizers will directly affect the overall combustion performance of solid propellants. Ammonium perchlorate, referred to as AP, is the most common oxidizer in solid propellants at this stage, and its thermal decomposition behavior will significantly affect the overall performance of solid propellants. Submicron, nano and other fine particles of AP and the addition of catalysts are usually used to regulate the initial decomposition temperature of AP.

[0003] AP is the most widely used oxidizer in composite solid propellants, accounting for about 70% of the solid mass, and its combustion performance directly determines the overall power performance of the engine. However, the thermal decomposition process of AP usually occurs at a higher temperature and involves multiple decomposition stages. The catalytic efficiency of AP thermal decomposition can be effectively improved by introducing a burning rate catalyst. Currently commonly used catalysts include metal nanoparticles, transition metal oxides, organic metal coordination compounds and carbon materials. However, the atomic utilization rate of the above catalysts is low, and most catalysts usually show a broad decomposition peak when catalyzing AP, indicating that the AP combustion kinetics is relatively slow and the heat release process is not concentrated, which is not conducive to the controllable use of composite solid propellants. In addition, these catalytic materials generally do not contain energy, which is not conducive to the heat release process. Therefore, it is crucial to develop new AP thermal decomposition catalytic materials with high atomic utilization efficiency and energy content. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a COFs material containing monodisperse Cu sites, a preparation method thereof, and an application in the thermal decomposition of ammonium perchlorate. The covalent organic framework material can effectively reduce the temperature required for the thermal decomposition reaction of ammonium perchlorate, reduce the activation energy of the reaction, and provide a new and effective catalytic material for the decomposition of ammonium perchlorate.

[0005] The present invention solves the above technical problems by the following technical means:

[0006] The present invention provides a method for preparing a COFs material containing monodisperse Cu sites, comprising the following steps:

[0007] Carbohydrazide and trialdehyde phloroglucinol are respectively weighed as main reaction raw materials, and a covalent organic framework precursor is obtained through a condensation reaction;

[0008] Weigh the covalent organic framework precursor and Cu[N(NO 2 ) 2 ] 2 The mixture is added into a solvent and dispersed by ultrasonic wave. The obtained suspension is stirred and reacted at room temperature for 10 to 15 hours, centrifuged and washed, and dried to obtain a COFs material containing monodispersed Cu sites.

[0009] In some embodiments, the molar ratio of carbohydrazide to trialdehyde phloroglucinol is (1.2-2.2):1.

[0010] In some embodiments, the preparation method of the covalent organic framework precursor is as follows:

[0011] Weigh carbohydrazide and trialdehyde pyrogallol separately and add them into an ampoule, then add 1,4-dioxane and 1,3,5-mesitylene, treat with ultrasound for 10 to 20 minutes, add triethylamine, evacuate, seal, and react at 110 to 130° C. for 2.5 to 3.5 days. Collect the solid product, wash, and dry to obtain a covalent organic framework precursor.

[0012] In some embodiments, the molar ratio of 1,4-dioxane to trialdehyde phloroglucinol is 150:1, the molar ratio of 1,4-dioxane to 1,3,5-mesitylene is 3:1, and the molar ratio of triethylamine added to trialdehyde phloroglucinol is 3:1.

[0013] In some embodiments, the drying condition is 55-65° C. for 10-15 hours.

[0014] In some embodiments, the covalent organic framework precursor and Cu[N(NO 2 ) 2 ] 2 The molar ratio is 1:(2~3).

[0015] In some embodiments, the solvent is methanol or ethanol.

[0016] On the other hand, an embodiment of the present application provides a COFs material containing monodisperse Cu sites, and the COFs material is prepared by the above-mentioned preparation method.

[0017] On the other hand, the embodiments of the present application provide the use of the above-mentioned COFs material containing monodisperse Cu sites in the thermal decomposition of ammonium perchlorate.

[0018] Preferably, the mass ratio of the COFs material to ammonium perchlorate is 1:(5-10).

[0019] The COFs material containing monodisperse Cu sites and the preparation method thereof are characterized in that the nitrogen-rich high-energy ligand carbohydrazide is used as an energetic building unit, and the energetic COFs precursor is prepared by reversible condensation with trialdehyde phloroglucinol, and then the copper-based energetic ion salt CuN[(NO 2 ) 2 ] 2 The complexation reaction with the nitrogen / oxygen sites in Tp-CBH obtains energetic metal-based COFs, i.e., COFs materials containing monodisperse Cu sites. During the thermal decomposition of AP, the above energetic metal-based COFs can achieve single-step rapid and concentrated decomposition of AP at a low temperature of 341.3°C, and the exothermic peak is narrow, which significantly reduces the temperature required for the thermal decomposition reaction of ammonium perchlorate and reduces the activation energy of the reaction, thus providing a new and effective catalytic material for the decomposition of ammonium perchlorate. The COFs material containing monodisperse Cu sites of the present invention can significantly advance the high-temperature decomposition peak of AP thermal decomposition, achieving excellent catalytic performance; at the same time, the presence of AP stabilizes the energetic metal-based COFs, which can not only improve the stability of the energetic metal-based COFs catalyst, but also promote the release of a large amount of heat in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is Tp-CBH-Cu-N(NO 2 ) 2 Schematic diagram of catalytic decomposition of ammonium perchlorate;

[0021] Figure 2 It is a schematic diagram of the synthesis process of COFs materials containing monodisperse Cu sites;

[0022] Figure 3 The COFs precursor prepared in Example 1 and Tp-CBH-Cu-N(NO 2 ) 2 X-ray diffraction patterns and infrared patterns;

[0023] Figure 4 The Tp-CBH-Cu-N(NO 2 ) 2 Synchrotron radiation characterization of

[0024] Figure 5 The Tp-CBH-Cu-N(NO 2 ) 2 Electron microscope images of

[0025] Figure 6 is a differential scanning calorimetry diagram of comparative application example 1;

[0026] Figure 7The COFs precursor prepared in Example 1 and Tp-CBH-Cu-N(NO 2 ) 2 Differential scanning calorimetry plots of the catalytic AP decomposition. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0028] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of objects. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more, for example, multiple processing units refer to two or more processing units, etc., multiple elements refer to two or more elements, etc.

[0029] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0030] The English letters in the present invention are interpreted as follows:

[0031] CBH: carbohydrazide; Tp: trialdehyde phloroglucinol; Tp-CBH: COFs precursor; Tp-CBH-Cu-N(NO 2 ) 2 : COFs materials containing monodisperse Cu sites; AP: ammonium perchlorate; THF: tetrahydrofuran; COFs: covalent organic framework materials; EtOH: ethanol.

[0032] The problems of low atomic utilization, high decomposition temperature and two decomposition stages in existing catalytic AP materials have seriously limited the performance of solid rocket engines. The present application provides a covalent organic framework material containing monodisperse Cu sites for catalyzing AP thermal decomposition. The atomic utilization is improved by chelating single-atom Cu in energetic COFs. The application of the covalent organic framework material containing monodisperse Cu sites in the present application to the AP thermal decomposition reaction can reduce the AP thermal decomposition temperature, reduce the activation energy of the reaction, and merge the decomposition stages into one stage, so that the energy release is more concentrated.

[0033] Specifically, the preparation method of the COFs material containing monodisperse Cu sites of the present application comprises the following steps: respectively weighing carbohydrazide and trialdehyde phloroglucinol as main reaction raw materials, and obtaining a covalent organic framework precursor through a condensation reaction; respectively weighing a covalent organic framework precursor and Cu[N(NO 2 ) 2 ] 2 The mixture is added into a solvent and dispersed by ultrasonic wave. The obtained suspension is stirred and reacted at room temperature for 10 to 15 hours, centrifuged and washed, and dried to obtain a COFs material containing monodispersed Cu sites.

[0034] Wherein, the molar ratio of carbohydrazide to trialdehyde phloroglucinol is (1.2-2.2):1.

[0035] Among them, the preparation method of the covalent organic framework precursor is as follows: weigh carbohydrazide and trialdehyde phloroglucinol respectively and add them into an ampoule, then add 1,4-dioxane and 1,3,5-mesitylene, ultrasonically treat for 10 to 20 minutes, add triethylamine, evacuate, seal, place at 110 to 130°C for reaction for 2.5 to 3.5 days, collect the solid product, wash, and dry to obtain a covalent organic framework precursor. Among them, the molar ratio of 1,4-dioxane to trialdehyde phloroglucinol is 150:1, the molar ratio of 1,4-dioxane to 1,3,5-mesitylene is 3:1, and the amount of triethylamine added is 3:1 with the molar ratio of trialdehyde phloroglucinol. The drying condition is 55 to 65°C for 10 to 15 hours.

[0036] Among them, the covalent organic framework precursor and Cu[N(NO 2 ) 2 ] 2 The molar ratio of is 1:(2-3), ensuring that the copper ions can fully coordinate with the nitrogen / oxygen sites in the COFs precursor. The solvent is methanol or ethanol.

[0037] The COFs material containing monodisperse Cu sites of the present application can be used in the thermal decomposition of ammonium perchlorate, wherein the mass ratio of the COFs material to ammonium perchlorate is 1:(5-10).

[0038] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0039] Example 1

[0040] The preparation method of the COFs material containing monodisperse Cu sites in this embodiment is as follows:

[0041] (1) Synthesis of COFs precursors

[0042] Tp (21 mg, 0.1 mmol) and CBH (13.5 mg, 0.15 mmol) were weighed into an ampoule, 1,4-dioxane (15 mmol) and 1,3,5-mesitylene (5 mmol) were added in turn, and triethylamine (0.3 mmol) was added after ultrasonic treatment for 10 min. A double-row tube device was used to perform three cycles of freezing-vacuuming-dissolving. Finally, the glass tube was sealed with a flame gun under vacuum and placed in a 120 ° C constant temperature oven for continuous heating reaction for 3 days. After the reaction was completed, the solid product was collected by vacuum filtration and washed with THF, and then the oligomer small molecules were removed by THF Soxhlet extraction, and vacuum dried at 60 ° C for 12 h to obtain the COFs precursor, which was recorded as Tp-CBH.

[0043] (2) Synthesis of energetic metal-based COFs

[0044] Tp-CBH (14.55 mg, 0.15 mmol) and Cu[N(NO 2 ) 2 ] 2 ·3H 2 O (148.5 mg, 0.45 mmol) was dispersed in 10 mL EtOH and stirred at room temperature for 12 h. The solid product was then centrifuged and washed five times with EtOH. The solid product was dried in a constant temperature oven at 60 °C overnight to obtain a COFs material containing monodispersed Cu sites, which was recorded as Tp-CBH-Cu-N(NO 2 ) 2 .

[0045] Example 2

[0046] The preparation method of the COFs material containing monodisperse Cu sites in this embodiment is as follows:

[0047] (1) Synthesis of COFs precursors

[0048] Tp (21 mg, 0.1 mmol) and CBH (13.5 mg, 0.15 mmol) were weighed into an ampoule, 1,4-dioxane (15 mmol) and 1,3,5-mesitylene (5 mmol) were added in turn, and triethylamine (0.3 mmol) was added after ultrasonic treatment for 10 min. A double-row tube device was used to perform three cycles of freezing-vacuuming-dissolving. Finally, the glass tube was sealed with a flame gun under vacuum and placed in a 110 ° C constant temperature oven for continuous heating and reaction for 2.5 days. After the reaction was completed, the solid product was collected by vacuum filtration and washed with THF, and then the oligomer small molecules were removed by THF Soxhlet extraction, and vacuum dried at 55 ° C for 14 h to obtain the COFs precursor, which was recorded as Tp-CBH.

[0049] (2) Synthesis of energetic metal-based COFs

[0050] Tp-CBH (14.55 mg, 0.15 mmol) and Cu[N(NO 2 ) 2 ] 2 ·3H 2 O (99 mg, 0.20 mmol) was dispersed in 10 mL EtOH and stirred at room temperature for 10 h. The solid product was then centrifuged and washed three times with EtOH. The solid product was dried in a constant temperature oven at 60 °C overnight under vacuum to obtain a COFs material containing monodispersed Cu sites, which was recorded as Tp-CBH-Cu-N(NO 2 ) 2 .

[0051] Example 3

[0052] The preparation method of the COFs material containing monodisperse Cu sites in this embodiment is as follows:

[0053] (1) Synthesis of COFs precursors

[0054] Tp (21 mg, 0.1 mmol) and CBH (19.8 mg, 0.22 mmol) were weighed into an ampoule, 1,4-dioxane (15 mmol) and 1,3,5-mesitylene (5 mmol) were added in sequence, and triethylamine (0.3 mmol) was added after ultrasonic treatment for 10 min. A double-row tube device was used to perform three cycles of freezing-vacuuming-dissolving. Finally, the glass tube was sealed with a flame gun under vacuum and placed in a 130 ° C constant temperature oven for continuous heating and reaction for 3 days. After the reaction was completed, the solid product was collected by vacuum filtration and washed with THF, and then the oligomer small molecules were removed by THF Soxhlet extraction, and vacuum dried at 65 ° C for 10 h to obtain the COFs precursor, which was recorded as Tp-CBH.

[0055] (2) Synthesis of energetic metal-based COFs

[0056] Tp-CBH (14.55 mg, 0.15 mmol) and Cu[N(NO 2 ) 2 ] 2 ·3H 2 O (82.5 mg, 0.25 mmol) was dispersed in 10 mL EtOH and stirred at room temperature for 15 h. The solid product was then centrifuged and washed five times with EtOH. The solid product was dried overnight in a constant temperature oven at 60 °C under vacuum to obtain a COFs material containing monodispersed Cu sites, which was recorded as Tp-CBH-Cu-N(NO 2 ) 2 .

[0057] Example 4

[0058] The preparation method of the COFs material containing monodisperse Cu sites in this embodiment is as follows:

[0059] (1) Synthesis of COFs precursors

[0060] Tp (21 mg, 0.1 mmol) and CBH (13.5 mg, 0.15 mmol) were weighed into an ampoule, 1,4-dioxane (15 mmol) and 1,3,5-mesitylene (5 mmol) were added in sequence, and triethylamine (0.3 mmol) was added after ultrasonic treatment for 10 min. A double-row tube device was used to perform three cycles of freezing-vacuuming-dissolving. Finally, the glass tube was sealed with a flame gun under vacuum and placed in a constant temperature oven at 115 ° C for continuous heating and reaction for 3.5 days. After the reaction was completed, the solid product was collected by vacuum filtration and washed with THF, and then the oligomer small molecules were removed by THF Soxhlet extraction, and then the reaction mixture was heated at 60 ° C. ℃ After vacuum drying for 15 h, the COFs precursor was obtained, which was denoted as Tp-CBH.

[0061] (2) Synthesis of energetic metal-based COFs

[0062] Tp-CBH (14.55 mg, 0.15 mmol) and Cu[N(NO 2 ) 2 ] 2 ·3H 2 O (148.5 mg, 0.45 mmol) was dispersed in 10 mL EtOH and stirred at room temperature for 13 h. The solid product was then centrifuged and washed five times with EtOH. The solid product was dried in a constant temperature oven at 60 °C overnight under vacuum to obtain a COFs material containing monodispersed Cu sites, which was denoted as Tp-CBH-Cu-N(NO 2 ) 2 .

[0063] Application Example 1

[0064] The COFs material containing monodisperse Cu sites prepared in Example 1 was used as a catalyst to catalyze the thermal decomposition of AP, as follows:

[0065] 5 mg of catalyst and 45 mg of AP were weighed and placed in a mortar, and 200 μL of methanol was added three times. After grinding evenly, a catalyst / AP composite sample with a mass ratio of 1:9 was prepared. In order to study the catalytic performance of the catalyst on the thermal decomposition reaction of ammonium perchlorate, the thermal decomposition reaction process of ammonium perchlorate can be obtained by differential scanning calorimetry. By analyzing the differential scanning calorimetry, in the range of 150-500 ° C, N 2 atmosphere, sample weight about 1 mg, covered alumina crucible, heating rates of 5, 10, 15, 20 °C / min.

[0066] Comparative application example 1

[0067] Without adding a catalyst, ammonium perchlorate itself shows a differential scanning calorimetry curve in the range of 150-500°C. 2 atmosphere, the sample amount was about 1 mg, the alumina crucible was covered, and the heating rates were selected at 5, 10, 15, and 20 °C / min to obtain the thermal decomposition reaction process.

[0068] Effect verification

[0069] By analyzing X-ray diffraction patterns, infrared, synchrotron radiation, and electron microscopy, the phase, unit cell parameters, functional groups, size, and other information of the products of Application Example 1 and Comparative Application Example 1 are tested, as follows:

[0070] The thermal decomposition of ammonium perchlorate itself and the Tp-CBH-Cu-N(NO 2 ) was used to catalyze the thermal decomposition of ammonium perchlorate. The test conditions were: temperature range from room temperature to 500°C, N 2 atmosphere, sample weight about 1 mg, covered alumina crucible, heating rate can be selected 5, 10, 15, 20 ℃ / min. By analyzing the differential scanning calorimetry curve, the thermal decomposition reaction process of ammonium perchlorate can be obtained.

[0071] Figure 3 The COFs precursor prepared in Example 1 and Tp-CBH-Cu-N(NO 2 ) 2 X-ray diffraction patterns and infrared images of Figure 3In the figure, a is the COFs precursor test results obtained by the sample powder X-ray experiment, the stacking mode results of the simulated precursor COFs, the Bragg line results of the AA stacking, and the post-modified Cu single atom catalyst Tp-CBH-Cu-N(NO 2 ) 2 The experimental test results of b are ligand carbohydrazide, trialdehyde phloroglucinol, precursor COFs, Cu single atom catalyst Tp-CBH-Cu-N(NO 2 ) 2 Infrared test results.

[0072] Figure 3 The data show that the experimental results of COFs precursor measured by powder X-ray diffraction match well with the simulated AA stacking mode; after post-modification with metal salts, the peak shape does not change significantly, indicating that the introduction of copper salts will not cause structural changes. At the same time, the diffraction angle of 26.62° has a high intensity, which corresponds to the diffraction peak of COF. <001> Face <001> The XRD experimental results shifted to a lower angle, indicating that the introduced copper dinitramide was chelated between the layers, causing a decrease in the interlayer spacing. 2 ) 2 Infrared characterization, such as Figure 3 As shown in b, compared with the monomer raw materials hydrazide and trialdehyde phloroglucinol, the -1 、1646cm -1 -NH 2 ,-C=OH disappears at 1610cm -1 、1589cm -1 The appearance of -CN-, C=O at 1326 cm -1 、1009cm -1 and 756cm -1 The display belongs to -NO 2 The symmetric stretching vibration signal peaks can be inferred from the post-synthetic modification strategy to encapsulate energetic anions in the COFs structure.

[0073] Further, the Tp-CBH-Cu-N(NO 2 ) 2 The synchrotron radiation test was carried out and the results are shown in Figure 4 .exist Figure 4 In the figure, a is the near-edge absorption test result, and b is the extended-edge test result.

[0074] Figure 4 Figure a shows that Tp-CBH-Cu-N(NO 2 )2 And the X-ray absorption near-edge structure curve of the reference sample at Cu K edge. 4 and Tp-CBH-Cu-N(NO 2 ) 2 The white peak is close to CuO, which indicates that the chemical valence state of the copper species is about +2. Figure 4 Figure b shows that Tp-CBH-Cu-N(NO 2 ) 2 The Fourier transform of the extended X-ray absorption fine structure spectrum is about There is a significant main peak at and Cu-N bonds in CuPc are very close, indicating that the Cu atoms in this material are connected to N or O atoms through coordination bonds.

[0075] The Tp-CBH-Cu-N(NO 2 ) 2 Conduct electron microscope test, see the results Figure 5 , where a is Tp-CBH-Cu-N(NO 2 ) 2 Transmission electron microscopy, b is Tp-CBH-Cu-N(NO 2 ) 2 Spherical aberration electron microscope.

[0076] like Figure 5 In the transmission electron microscope image of middle a, no Cu agglomeration phenomenon is observed, and Cu, N, O, and C are evenly distributed. The reason is that the single-atom state of Cu is too small to exceed the TEM detection limit, suggesting that Cu is distributed on COFs in a single-atom state. Figure 5 In the spherical aberration electron microscope photograph in middle b, single atomic bright spots of Cu can be clearly observed, indicating that Cu is distributed in a single atomic state.

[0077] Figure 6 To compare the differential scanning calorimetry diagram of Application Example 1, the decomposition results of AP itself at different heating rates when no catalyst is added. Figure 6 It can be seen that when no catalyst is added, the thermal decomposition behavior of pure AP can be divided into three processes: taking a heating rate of 5°C / min as an example, when the temperature reaches 243.6°C, AP undergoes a crystal transformation from orthorhombic to cubic, and absorbs a certain amount of heat, which is the crystal transformation stage; at 301.6°C, AP partially decomposes to generate intermediates and releases a certain amount of heat, which is the low-temperature decomposition stage; at 410.3°C, AP completely decomposes into volatile products and releases a large amount of heat, which is the high-temperature decomposition stage.

[0078] Figure 7 The COFs precursor prepared in Example 1 and Tp-CBH-Cu-N(NO 2 ) 2 Differential scanning calorimetry diagrams of AP decomposition, where a is the COFs precursor and b is Tp-CBH-Cu-N(NO 2 ) 2 of.

[0079] from Figure 7 It can be seen from a that when COFs precursor is used as a catalyst, taking a heating rate of 5°C / min as an example, there is no obvious effect on the crystal transformation stage of AP, and the low-temperature decomposition stage and the high-temperature decomposition stage are somewhat advanced. Figure 7 It can be found in b that, taking the heating rate of 5°C / min as an example, the addition of catalyst has no obvious effect on the crystal transformation stage of AP, but the low-temperature decomposition stage and high-temperature decomposition stage of AP are combined into one and shifted to the low-temperature zone, and the heat release is more concentrated. 2 ) 2 The material advances the high temperature decomposition peak of AP to 341.3℃, and reduces the high temperature decomposition peak temperature of AP by 69℃. Figure 7 b It can be found that, taking the heating rate of 5℃ / min as an example, the addition of catalyst has no obvious effect on the crystal transformation stage of AP, but the low-temperature decomposition stage and high-temperature decomposition stage of AP are combined into one and shifted to the low-temperature zone, and the heat release is more concentrated. 2 ) 2 The material advances the high temperature decomposition peak of AP to 341.3°C, and reduces the high temperature decomposition peak temperature of AP by 69°C. The above results show that the Cu single atom catalyst Tp-CBH-Cu-N(NO 2 ) 2 Application potential of catalytic thermal decomposition of perchloric acid.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should be included in the scope of the claims of the present invention. The techniques, shapes, and structural parts not described in detail in the present invention are all known technologies.

Claims

1. A method for preparing a COFs material containing monodisperse Cu sites, characterized in that: The following steps are involved: Carbohydrazide and trialdehyde phloroglucinol are respectively weighed as main reaction raw materials, and a covalent organic framework precursor is obtained through a condensation reaction; The covalent organic framework precursor and Cu[N(NO2)2]2 were weighed separately and added to the solvent, and ultrasonically dispersed. The obtained suspension was stirred and reacted at room temperature for 10 to 15 hours, centrifuged and washed, and dried to obtain a COFs material containing monodisperse Cu sites.

2. The method for preparing a COFs material containing monodisperse Cu sites according to claim 1, characterized in that: The molar ratio of the carbohydrazide to trialdehyde phloroglucinol is (1.2-2.2):

1.

3. The method for preparing a COFs material containing monodisperse Cu sites according to claim 2, characterized in that: The preparation method of the covalent organic framework precursor is as follows: Weigh carbohydrazide and trialdehyde pyrogallol separately and add them into an ampoule, then add 1,4-dioxane and 1,3,5-mesitylene, treat with ultrasound for 10 to 20 minutes, add triethylamine, evacuate, seal, and react at 110 to 130° C. for 2.5 to 3.5 days. Collect the solid product, wash, and dry to obtain a covalent organic framework precursor.

4. The method for preparing a COFs material containing monodisperse Cu sites according to claim 3, characterized in that: The molar ratio of 1,4-dioxane to trialdehyde phloroglucinol is 150:1, the molar ratio of 1,4-dioxane to 1,3,5-mesitylene is 3:1, and the molar ratio of triethylamine added to trialdehyde phloroglucinol is 3:

1.

5. The method for preparing a COFs material containing monodisperse Cu sites according to claim 3, characterized in that: The drying condition is 55-65° C. for 10-15 hours.

6. The method for preparing a COFs material containing monodisperse Cu sites according to claim 1, characterized in that: The molar ratio of the covalent organic framework precursor to Cu[N(NO2)2]2 is 1:(2-3).

7. The method for preparing a COFs material containing monodisperse Cu sites according to claim 1, characterized in that: The solvent is methanol or ethanol.

8. A COFs material containing monodisperse Cu sites, characterized in that: The COFs material is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the COFs material according to claim 8 in thermal decomposition of ammonium perchlorate.

10. The use according to claim 9, characterized in that: The mass ratio of the COFs material to ammonium perchlorate is 1:(5-10).

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