Inorganic-organic silicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves

Abstract

The invention belongs to the technical field of high polymer materials, and particularly relates to a nitrogen-containing inorganic-organic silicon-based hybrid material for adsorbing CO2 or a wave-absorbing material and a preparation method of the nitrogen-containing inorganic-organic silicon-based hybrid material. Aiming at the problems of low nitrogen content when the nitrogen-containing inorganic-organic silicon-based material is used as a CO2 adsorbent and solid-solid reaction when the nitrogen-containing inorganic-organic silicon-based material is used as a wave-absorbing material at present, the nitrogen-containing inorganic-organic silicon-based material disclosed by the invention has the advantages that an aminolysis-polymerization reaction is carried out on a-NH2 group at the tail end of an amino compound and Si < 4 + > cations of a silicon source, so that the nitrogen content of the material is obviously increased, and the temperature required by nitrogen doping is reduced. The inorganic-organic silicon-based hybrid material is rich in Si-N bonds and high in N content, CO2 adsorption performance of the material is improved, and a high-nitrogen-content wave-absorbing material is prepared under the low-temperature condition. The method is simple in preparation process flow, easy in condition control, good in economical efficiency and good in industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to nitrogen-containing inorganic-organosilicon-based hybrid materials for adsorbing CO2 or absorbing microwaves and their preparation methods. Background Technology

[0002] In recent years, nitrogen-containing inorganic-organosilicon-based materials have gradually attracted widespread attention from researchers. The inorganic silicon component in these materials gives them excellent thermal and mechanical properties, while the nitrogen-containing organic carbon component also endows them with certain functionalities.

[0003] One of the functions of nitrogen-containing organic carbon components in materials is as an adsorbent for acidic molecules. Because the nitrogen atoms in the material possess a pair of unshared lone pairs of electrons, they can act as Lewis base centers, adsorbing acidic molecules such as CO2 emissions from industrial sources. This will not only benefit environmental protection but also contribute to achieving my country's "dual carbon" goals. Patent CN 106902613 A discloses a method for preparing an amino-functionalized porous CO2 adsorbent material. The method involves thoroughly mixing porous materials such as silica, organic amine modifiers (ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, polyethylenepolyamine), and dispersants (silane coupling agents, titanate coupling agents, Tween, higher fatty acids, polyacrylates, and polymethacrylates). Then, a heating and drying process is used to allow the amino modifiers to fully react with the porous materials, yielding the final adsorbent material. Patent CN 113877539 A discloses a CO2 solid adsorbent and its preparation and application. The method involves adding a porous carrier such as mesoporous silica to a solution containing organic amines (ethylenediamine, diethanolamine, polyethyleneamine, pentaethylenehexamine, polypropyleneimine, polyethyleneimine, tetraethylenepentamine, triethylenetetramine, diethylenetriamine) and metal salts. After stirring and impregnating for a period of time, the final material is obtained by two steps: evaporating the solvent and drying.

[0004] In the preparation methods of these nitrogen-containing inorganic-organosilicon-based materials, nitrogen-containing organic amines are anchored onto the surface of porous silica through mechanical mixing-heating or chemical impregnation. Generally, these anchoring sites are unsaturated sites on the surface (edges, corners, and ridges) and surface functional group sites. On porous silica surfaces, these anchoring sites are often limited, which frequently results in a limited number of organic amines introduced onto the material surface. Since the material's ability to adsorb CO2 is closely related to its nitrogen content, the limited number of amines will restrict the material's CO2 adsorption capacity.

[0005] Besides acting as an adsorbent for acidic molecules, nitrogen-containing organic carbon components also endow inorganic-organosilicon-based materials with another function: microwave absorption properties (Cui Sikai et al., In-situ reaction preparation and mechanism of silicon carbide microwave absorbing materials. Journal of Materials Research, 2024, 38(9), 659-668, Patent CN 1025 04760 A). As a dielectric microwave absorbing material, silicon carbide has advantages such as high temperature resistance, corrosion resistance, oxidation resistance, and high mechanical strength. Studies have found that the microwave absorption properties of silicon carbide are closely related to its structure and composition. Doping silicon carbide with nitrogen to adjust the conductivity of the material can improve the dielectric loss performance of the material, thereby enhancing the microwave absorption performance.

[0006] Patent CN 114262230 A discloses a silicon nitride-silicon carbide porous ceramic microwave absorbing material and its preparation method. The method involves ball milling SiC or Si, a catalyst (ferrocene, FeCl2•4H2O and / or FeCl3), a pore-forming agent (polymethyl methacrylate), a binder, and a solvent to obtain a mixed slurry. This slurry is then dried, pressed, dewaxed under negative pressure, and sintered (1250℃-1550℃, N2 atmosphere) to obtain the final material. Patent CN 116040634 A discloses a novel method for preparing three-dimensional porous silicon carbide aerogel (SiCNF). This method includes two steps: calcination and silicon infiltration. The raw material, *Lactuca sativa*, is calcined in argon at 900℃ to obtain three-dimensional porous carbon. This carbon is then placed on top of Si powder in a crucible and calcined under oxygen-free conditions at 1300℃ to obtain the final sample. Patent CN 105293499 A discloses a method for preparing B and N co-doped silicon carbide nano-absorbing materials. The method involves mixing and sieving Si powder, carbon black powder C, amorphous boron powder B, silicon nitride powder, and polytetrafluoroethylene powder, and then placing the mixture in a vacuum-atmosphere hot-pressing sintering furnace. The mixture undergoes a high-temperature self-propagating reaction at 1350℃-1450℃ in an N2 atmosphere, followed by a decarburization step at 550℃-650℃ to obtain the final material.

[0007] In the preparation methods of these nitrogen-doped silicon carbide-based microwave absorbing materials, both the nitrogen-containing component (such as silicon nitride, porous carbon, etc.) and the silicon-containing component (such as Si powder, SiC, etc.) are solid substances. Infiltrating nitrogen into the silicon-containing component requires sufficient contact and reaction between the two solid substances, i.e., a solid-solid reaction. Compared to gas-liquid, liquid-liquid, or liquid-solid reactions, solid-solid reactions often require higher temperatures to achieve. Therefore, the solid-solid reactions in the aforementioned patents all require temperatures above 1200℃. High temperatures are not only detrimental to industrialization but also increase the energy consumption of the process. Furthermore, the amount of nitrogen doping is limited during the solid-solid reaction, which is unfavorable for obtaining microwave absorbing materials with high nitrogen doping levels. Summary of the Invention

[0008] To address the problems of low nitrogen content when used as a CO2 adsorbent and solid-solid reaction when used as a microwave absorbing material in current nitrogen-containing inorganic-organosilicon-based materials, this invention provides an inorganic-organosilicon-based nitrogen-containing hybrid material precursor for CO2 adsorption and microwave absorbing materials, and its preparation method. This invention significantly promotes the nitrogen content of the material, reduces the temperature required for nitrogen doping, thereby improving the CO2 adsorption performance of the material and enabling the preparation of high-nitrogen-content microwave absorbing materials under low-temperature conditions.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] An inorganic-organosilicon-based nitrogen-containing hybrid material that adsorbs CO2 and absorbs electromagnetic waves, the material having the structural formula satisfying Si 4+ (NH-R-NH)n, where -NH-R-NH- is an organic amine ligand, -R- represents an organic group, and n represents the number of organic amine ligands, n=2-4.

[0011] Furthermore, the inorganic-organosilicon-based nitrogen-containing hybrid material has a nitrogen content of 5.1 wt% to 16.0 wt% and a static CO2 adsorption capacity of 1.2 to 5.0 mmol / g. -1 The specific surface area of ​​multi-point BET is 10.0~600.0 m². 2 / g, with an average adsorption pore size of 2.0~50.0nm.

[0012] Furthermore, the inorganic-organic silicon-based nitrogen-containing hybrid material exhibits microwave absorption performance of -25dB to -10dB and an effective absorption frequency of 8.2GHz to 12.1GHz, where R < -10dB, and -10dB is equivalent to absorbing 90% of electromagnetic waves.

[0013] A method for preparing an inorganic-organosilicon-based nitrogen-containing hybrid material that adsorbs CO2 and absorbs electromagnetic waves includes the following steps:

[0014] Step 1: Thoroughly mix the silicon source with the solvent to prepare solution 1; thoroughly mix the organic amine with the solvent to prepare solution 2; mix solution 1 and solution 2 to obtain a suspension;

[0015] Step 2: Heat the suspension to react;

[0016] Step 3: After the reaction is complete, filter, wash and dry to obtain inorganic-organosilicon-based nitrogen-containing hybrid material.

[0017] Organic amine compounds contain a characteristic amino (-NH2) functional group in their molecular structure. The nitrogen atom in this functional group possesses a lone pair of electrons, giving it strong coordination ability, allowing it to react with the central silicon ion (Si). 4+ The interaction occurs specifically as follows: nitrogen atoms attack Si through their lone pairs of electrons. 4+Electron pair sharing is achieved through an aminolysis reaction, constructing a -Si-NH- covalent bond. The organic amine selected in this patent is a diamino-terminated compound (general structural formula H2N-R-NH2, where R is a hydrocarbon group). In this type of amine molecule, one -NH2 group preferentially bonds with Si. 4+ An aminolysis reaction occurs, forming chemical bonds and ultimately generating Si. 4+ (NH-R-NH2) n Type precursor, where -NH-R-NH2 is the organic amine ligand, -R- is the organic linking unit in the ligand, and n represents the interaction with a single Si 4+ The number of coordinated ligands (n=2-4). In the precursor, the organic amine ligand (-NH-R-NH2) retains unreacted -NH2 groups, which can further undergo intermolecular polymerization to form (NH-R-NH) ligands. n The polymer structure consists of repeating units. Within this polymer system, the -NH-R-NH- ligand acts as a molecular bridge: it binds to different Si groups through its active sites at both ends. 4+ Coordination, to disperse Si 4+ Ions connect in series to form a three-dimensional cross-linked network, ultimately forming an inorganic-organic silicon-based hybrid material. Due to the central Si... 4+ The ions form chemical bonds only with N atoms, thus the material has a large number of Si-N bonds and a high N content.

[0018] Furthermore, in the structural formula of the material, the organic amine ligand -NH-R-NH- has an organic group in its -R- group, which may or may not contain an amino group. For NH2-R-NH2 type organic amines, the two inherent terminal amino groups (-NH2) in their molecular structure can provide sufficient active sites for the preparation of inorganic-organic hybrid materials. Based on this, in the formed -NH-R-NH- type organic amine ligand, the bridging group R can be either a structural unit without an amino group or a polyamine fragment containing an amino group.

[0019] Furthermore, the silicon source includes, but is not limited to, any one or a combination of tetraethyl orthosilicate, tetramethyl orthosilicate, triethoxysilane, methyltriethoxysilane, silicon carbonate, silicon halide, silicon nitrate, and silicon acetate. The covalent bonds (Si-OR, Si-OCOO-, Si-X, Si-ONO2, etc.) between the silicon center and the substituents are easily attacked and broken by nucleophiles (such as water, alcohols, tetrahydrofuran, pyridine, etc.), resulting in free metal ions (Si...). 4+ It readily undergoes aminolysis with the amino groups of amine compounds, which is conducive to the formation of Si-N bonds.

[0020] Furthermore, the solvent refers to a solvent capable of dissolving both the silicon source and the organic amine ligand, including both inorganic and organic solvents, specifically water, methanol, ethanol, tetrahydrofuran, pyridine, dichloromethane, carbon tetrachloride, benzene, and toluene. Any one of these solvents, or a combination of multiple solvents, can be selected during use. The solvent used in this system possesses excellent dissolving and dispersing capabilities for both silicon ions and amine compounds, enabling uniform mixing at the molecular level. This provides sufficient contact conditions for the amino group (-NH2) in the amine molecule and the silicon ion, thereby ensuring the efficient occurrence of the aminolysis reaction. In addition, given that the aminolysis reaction is exothermic, the solvent can rapidly conduct and dissipate the heat of reaction through its own heat transfer and heat capacity characteristics, effectively suppressing sudden increases in local temperature within the system and thus reducing the probability of side reactions.

[0021] Furthermore, the organic amine is any one or a combination of several of the following: ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 1,6-hexanediamine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, diethylenetriamine, phenyl-1,2,3-triamine, and N,N-diethyldivinyltriamine. The aforementioned organic amine molecules contain at least two terminal amino groups (-NH2), providing the active sites required for the preparation of inorganic-organic hybrid materials, satisfying coordination and bonding requirements. In addition, the differences in the hydrocarbon structure of the organic amine molecule (such as different carbon chain lengths or the presence of aromatic ring structures such as benzene rings) can significantly regulate the polydentate coordination configuration and the rigidity / flexibility characteristics of the ligand; simultaneously, changes in the hydrocarbon structure can adjust the electron cloud density of the nitrogen atom in the ligand through electronic effects (such as inductive effects and conjugation effects), thereby achieving precise control over the reactivity of the amino group (-NH2).

[0022] Furthermore, the mixing temperature in step 1 is 0℃~50℃. A reaction temperature that is too low will significantly reduce the amination kinetics of silicon ions and amines, hindering the efficient reaction; a temperature that is too high will cause the amination reaction to be violent, with the system releasing a large amount of heat in a short time, leading to a sudden rise in local temperature. This local overheating will damage the stability of amines, causing them to decompose or undergo structural changes, while simultaneously providing thermodynamic conditions for side reactions such as silicon species self-polymerization and amine oxidation / crosslinking, reducing the selectivity of the target reaction and the purity of the product.

[0023] Furthermore, the heating reaction temperature in step 2 is 100℃~200℃, and the reaction time is 1 h~216 h. The core objectives of this step can be summarized in two points: (1) to provide suitable thermodynamic and kinetic conditions for the aminolysis reaction of silicon ions and amine compounds, ensuring that the reaction proceeds towards complete conversion; (2) to drive the Si generated by the aminolysis reaction. 4+The (NH-R-NH)n type precursor undergoes further polymerization to ultimately construct the target inorganic-organosilicon-based hybrid material. Low temperatures or insufficient time limit the conversion efficiency of the amine hydrolysis reaction and result in incomplete precursor polymerization, making it difficult to form a structurally complete hybrid material. Conversely, excessively high temperatures or excessively long times weaken the stability of amine compounds, induce side reactions such as decomposition and oxidation, and may also lead to excessive condensation or cross-linking of silicon-based species, reducing the structural regularity and performance controllability of the target hybrid material.

[0024] Furthermore, the drying temperature in step 3 is 120℃~500℃, and the drying time is 0.5 h~24 h. Low temperatures reduce the evaporation rate of solvents and byproducts, making efficient removal difficult; high temperatures easily lead to thermal decomposition of organic components, damaging the structural integrity and component homogeneity of the material. Too short a time will result in insufficient removal of solvents and byproducts, leaving residues that affect performance; too long a time will increase energy consumption, prolong the cycle, leading to increased costs and reduced economic efficiency.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] (1) This invention utilizes the -NH2 group at the end of an amino compound, and the silicon source Si 4+ The cations undergo aminolysis-polymerization, which significantly increases the nitrogen content of the material and lowers the temperature required for nitrogen doping. Nitrogen content has a clear and crucial impact on the microwave absorption performance of the material. The core of this effect is to directly determine the absorption efficiency by controlling the dielectric properties and crystal quality of the material, and there exists an optimal doping range. The inorganic-organosilicon-based nitrogen-containing hybrid material of this application has a nitrogen content of 5.1 wt% to 16.0 wt%, which significantly affects the microwave absorption performance. The core of this effect is to indirectly optimize impedance matching and dielectric loss by forming a specific phase (Si3N4) and controlling the microstructure, thereby improving the microwave absorption performance.

[0027] (2) The preparation process of the present invention is simple and the conditions are easy to control. No catalyst or inorganic acid / base is needed as a reaction medium throughout the process.

[0028] (3) When selecting raw materials and solvents, this invention avoids high-priced organic raw materials and solvent systems, which not only reduces preparation costs and has outstanding economic benefits, but also lays the foundation for subsequent industrial promotion and application, and has broad industrial application prospects. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 X-ray photoelectron spectroscopy of nitrogen-containing inorganic-organic hybrid materials (corresponding to Example 1). Figure 1 a represents the overall spectrum of C, O, N, and Si elements. Figure 1 b represents the N-element spectrum and fitting results);

[0031] Figure 2 Specific surface area and pore size analysis of nitrogen-containing inorganic-organic hybrid materials (corresponding to Example 2);

[0032] Figure 3 Transmission infrared analysis of nitrogen-containing inorganic-organic hybrid materials (corresponding to Examples 1 and 6; curve a is the infrared curve of the Si-N and Si-C bond structure of CO2 adsorption, and curve b is the infrared curve of the Si-N and Si-C bond structure of the microwave absorbing material). Detailed Implementation

[0033] To gain a deeper understanding of this invention, we will provide a comprehensive and detailed description. However, this invention has various implementations and is not limited to the specific examples listed herein. These examples are presented to enhance a full understanding of the disclosure of this invention.

[0034] Example 1

[0035] Step 1: Accurately weigh 3.80 g of tetraethyl orthosilicate (Si(OC2H5)4) and place it in a 250 mL dry beaker. Add 150 mL of dichloromethane and treat with magnetic stirring at 25 °C for 1 hour until a homogeneous, colorless, and transparent solution is formed. This solution is designated as Solution 1. Separately, add 2.9 g of o-phenylenediamine (o-H2NC6H4NH2) and 100 mL of anhydrous methanol to a 150 mL beaker and treat with mechanical stirring at 25 °C for 0.8 hours to obtain Solution 2. Slowly add Solution 1 dropwise through a constant pressure dropping funnel to a 500 mL round-bottom flask containing Solution 2 and treat with magnetic stirring at 30 °C for 1 hour to form a suspension.

[0036] Step 2: Transfer the above suspension to a 100°C oil bath and react for 120 hours;

[0037] Step 3: After the reaction was complete, the product was filtered, washed with methanol, and dried at 170°C for 20 hours to obtain a powdered nitrogen-containing inorganic-organosilicon-based hybrid material. XPS analysis confirmed the formation of Si-N bonds. Figure 1 The material exhibited Si-N and Si-C bond structures during transmission infrared characterization. Figure 3 a) The multi-point BET specific surface area of ​​this material is 599.91 m². 2 The material exhibits a nitrogen content of 11.0 wt% and a static CO2 adsorption capacity of 5.0 mmol / g, with an average pore size of 2.01 nm. Elemental analysis revealed a static CO2 adsorption capacity of 5.0 mmol / g. -1The material has a wave absorption performance of -22dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 11.2GHz.

[0038] Example 2

[0039] Step 1: Accurately weigh 5.00 g of tetramethyl orthosilicate (Si(OCH3)4) and place it in a 500 mL dry three-necked flask. Add 100 mL of anhydrous ethanol and 200 mL of toluene. Treat at 0 °C with magnetic stirring for 0.5 hours until a colorless and transparent solution is formed, which is recorded as solution 1. Separately weigh 3.00 g of 1,3-propanediamine (H2NCH2CH2CH2NH2) and 80 mL of tetrahydrofuran and add them to a 100 mL dry flask. Treat at 35 °C with mechanical stirring for 0.8 hours to obtain solution 2. Slowly add solution 1 dropwise to the 500 mL three-necked flask containing solution 2 through a constant pressure dropping funnel. Treat at 40 °C in air atmosphere with magnetic stirring for 2 hours to form a suspension.

[0040] Step 2: Add the above suspension to a high-pressure reactor and treat it at 110°C for 60 hours;

[0041] Step 3: After the reaction is complete, the product is filtered, washed with tetrahydrofuran, and dried at 120°C for 2 hours to obtain a porous nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​560.15 m². 2 The material exhibits a nitrogen content of 16.0 wt% and a static CO2 adsorption capacity of 2.5 mmol / g, with an average pore size of 5.93 nm. Elemental analysis revealed a static CO2 adsorption capacity of 2.5 mmol / g. -1 The material has a wave absorption performance of -25dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 12.1GHz.

[0042] Example 3

[0043] Step 1: Weigh 4.50 g of triethoxysilane (HSi(OC2H5)3) and place it in a 500 mL dry three-necked flask. Add 150 mL of tetrahydrofuran and treat at 15 °C with magnetic stirring for 0.8 hours. This is recorded as solution 1. Separately, weigh 3.2 g of 1,2-propanediamine (H2NCH2CH2CH2NH2) and add it to a 150 mL dry flask. Add 80 mL of carbon tetrachloride and treat at 25 °C with mechanical stirring for 1.5 hours to obtain solution 2. Slowly add solution 2 dropwise to the three-necked flask containing solution 1 through a constant pressure dropping funnel. Treat at 30 °C in air atmosphere with magnetic stirring for 0.8 hours to form a suspension.

[0044] Step 2: Add the above suspension to a high-pressure reactor and treat it at 120°C for 30 hours;

[0045] Step 3: After the reaction is complete, the product is filtered, washed with dichloromethane, and dried at 480℃ for 24 hours to obtain a porous nitrogen-containing inorganic-organosilicon-based hybrid material with a multi-point BET specific surface area of ​​10.01 m². 2 The material exhibits an adsorption capacity of 1.2 mmol / g, an average pore size of 49.92 nm, a nitrogen content of 5.1 wt% determined by elemental analysis, and a static CO2 adsorption capacity of 1.2 mmol / g. -1 The material has a wave absorption performance of -10dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 8.2GHz.

[0046] Example 4

[0047] Step 1: Accurately weigh 6.00 g of methyltriethoxysilane (CH3Si(OC2H5)3) and place it in a 100 mL dry three-necked flask. Add 50 mL of anhydrous methanol and 30 mL of benzene, and treat with magnetic stirring at 35 °C for 0.8 hours. This is recorded as solution 1. Separately weigh 4.8 g of 1,6-hexanediamine (H2N(CH2)6NH2) and add it to a 100 mL dry flask. Add 50 mL of water and 20 mL of pyridine, and treat with constant temperature water bath at 25 °C and mechanical stirring for 0.5 hours to obtain a colorless and transparent solution 2. Slowly add solution 2 dropwise to the three-necked flask containing solution 1 through a constant pressure dropping funnel, and treat with magnetic stirring at 0 °C for 1.5 hours to form a suspension.

[0048] Step 2: Add the above suspension to a high-pressure reactor and treat it at 200°C for 1 hour;

[0049] Step 3: After the reaction was complete, the product was filtered, washed with toluene, and dried at 440℃ for 6 hours to obtain a dark brown porous nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​93.25 m². 2 The material exhibits a nitrogen content of 7.3 wt% and a static CO2 adsorption capacity of 1.7 mmol / g, with an average pore size of 23.06 nm. Elemental analysis revealed a static CO2 adsorption capacity of 1.7 mmol / g. -1 The material has a wave absorption performance of -15dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 8.4GHz.

[0050] Example 5

[0051] Step 1: Weigh 5.20g of silicon carbonate (Si(CO3)2) into a 150mL dry three-necked flask, add 80mL of pyridine, and treat at 30℃ with magnetic stirring for 1 hour until a colorless and transparent solution is formed, which is recorded as solution 1; Separately weigh 3.60g of p-phenylenediamine (p-H2NC6H4NH2) into a 100mL dry flask, add 30mL of anhydrous methanol, and treat at 0℃ with mechanical stirring for 0.5 hours to obtain transparent solution 2; Slowly add solution 2 dropwise to the three-necked flask containing solution 1 through a constant pressure dropping funnel, and treat at 25℃ with magnetic stirring for 0.8 hours to form a suspension;

[0052] Step 2: Add the above suspension to a high-pressure reactor and treat it at 140°C for 80 hours;

[0053] Step 3: After the reaction is complete, the product is filtered, washed with methanol, and dried at 350℃ for 8 hours to obtain a black powdery nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​383.25 m². 2 The material exhibits a nitrogen content of 10.6 wt% and a static CO2 adsorption capacity of 2.2 mmol / g, with an average pore size of 8.27 nm. Elemental analysis revealed a static CO2 adsorption capacity of 2.2 mmol / g. -1 The material has a wave absorption performance of -20dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 10.5GHz.

[0054] Example 6

[0055] Step 1: Weigh 4.80g of silicon tetrachloride and place it in a 150mL dry beaker. Add 100mL of anhydrous methanol and treat at 25℃ with magnetic stirring for 0.8 hours until a homogeneous colorless solution is formed, which is recorded as solution 1. Separately, weigh 5.20g of diethylenetriamine (H2NCH2CH2NHCH2CH2NH2) and add it to a 100mL beaker. Add 40mL of anhydrous ethanol and 20mL of benzene and treat at 40℃ with mechanical stirring for 2 hours to obtain a transparent solution 2. Slowly add solution 1 dropwise through a constant pressure dropping funnel to a 250mL three-necked flask containing solution 2 and treat at a constant temperature water bath at 15℃ with magnetic stirring for 0.8 hours to form a light yellow suspension.

[0056] Step 2: Treat the above suspension in an oil bath at 160°C with magnetic stirring for 216 hours;

[0057] Step 3: After the reaction is complete, the product is filtered, washed with dichloromethane, and dried at 500℃ for 0.5 hours to obtain a powdered nitrogen-containing inorganic-organosilicon-based hybrid material. Transmission infrared spectroscopy characterization of this material reveals Si-N and Si-C bond structures. Figure 3 (b) The multi-point BET specific surface area of ​​this material is 126.34 m².2 The material exhibits a nitrogen content of 6.8 wt% and a static CO2 adsorption capacity of 1.5 mmol / g, with an average pore size of 10.85 nm. Elemental analysis revealed a static CO2 adsorption capacity of 1.5 mmol / g. -1 The material has a wave absorption performance of -12dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 8.3GHz.

[0058] Example 7

[0059] Step 1: Weigh 6.50g of silicon nitrate (Si(NO3)4) into a 100mL dry beaker, add 50mL of deionized water, and treat at 50℃ with magnetic stirring for 1 hour until a homogeneous colorless solution is formed, which is recorded as solution 1; Separately weigh 4.20g of benzene-1,2,3-triamine (C6H3(NH2)3) into a 100mL beaker, add 50mL of pyridine, and treat at 30℃ with mechanical stirring for 1 hour to obtain a pink transparent solution 2; Slowly add solution 1 dropwise through a constant pressure dropping funnel to a 250mL round-bottom flask containing solution 2, and treat at 35℃ with magnetic stirring for 0.8 hours to form a suspension;

[0060] Step 2: Treat the above suspension in an oil bath at 180°C with mechanical stirring for 90 hours;

[0061] Step 3: After the reaction is complete, the product is filtered, washed with tetrahydrofuran, and dried at 450℃ for 15 hours to obtain a powdered nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​69.32 m². 2 The material exhibits a nitrogen content of 5.1 wt% and a static CO2 adsorption capacity of 1.2 mmol / g, with an average pore size of 16.03 nm. Elemental analysis revealed a static CO2 adsorption capacity of 1.2 mmol / g. -1 The material has a wave absorption performance of -10dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 8.2GHz.

[0062] Example 8

[0063] Step 1: Weigh 5.80g of silicon acetate (Si(CH3COO)4) into a 100mL beaker, add 60mL of anhydrous ethanol, and treat at 25℃ with magnetic stirring for 1.5 hours until a homogeneous colorless solution is formed, which is recorded as solution 1; Separately weigh 7.2g of N,N-diethyldivinyltriamine ((C2H5)2NCH2CH2NHCH2CH2NH2) into a 150mL dry flask, add 50mL of anhydrous ethanol, and treat at 15℃ with mechanical stirring for 0.8 hours to obtain solution 2; Slowly add solution 1 dropwise through a constant pressure dropping funnel to a 250mL three-necked flask containing solution 2, and treat at 50℃ with magnetic stirring for 1 hour to form a pale yellow suspension;

[0064] Step 2: Treat the above suspension in an oil bath at 200°C with magnetic stirring for 120 hours;

[0065] Step 3: After the reaction is complete, the product is filtered, washed with deionized water, and dried at 250℃ for 18 hours to obtain a bulk nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​298.50 m². 2 The material exhibits a nitrogen content of 12.5 wt% and a static CO2 adsorption capacity of 3.0 mmol / g, with an average pore size of 6.87 nm. Elemental analysis revealed a static CO2 adsorption capacity of 3.0 mmol / g. -1 The material has a wave absorption performance of -23dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 11.8GHz.

[0066] Example 9

[0067] Step 1: Weigh 3.00 g of tetraethyl orthosilicate (Si(OC2H5)4) and 4.20 g of silicon nitrate (Si(NO3)4) into a 200 mL dry three-necked flask, add 20 mL of pyridine and 100 mL of deionized water, and treat at 40 °C with magnetic stirring for 2 hours to form a light grayish-white transparent solution, which is denoted as solution 1; Separately weigh 3.60 g of m-phenylenediamine (m-H2NC6H4NH2) into a 250 mL dry flask, add 150 mL of toluene, and treat at 30 °C with mechanical stirring for 0.8 hours to obtain solution 2; Slowly add solution 2 dropwise through a constant pressure dropping funnel to the three-necked flask containing solution 1 under air atmosphere, and treat at 25 °C with magnetic stirring for 0.5 hours to form a suspension;

[0068] Step 2: Add the above suspension to a high-pressure reactor and treat it at 100°C for 1 hour;

[0069] Step 3: After the reaction is complete, the product is filtered, washed with ethanol, and dried at 150°C for 20 hours to obtain a porous nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​20.20 m². 2The material exhibits a CO2 adsorption capacity of 16.67 nm per g, with an average pore size of 16.67 nm. Elemental analysis revealed a nitrogen content of 10.6 wt% and a static CO2 adsorption capacity of 2.2 mmol / g. -1 The material has a wave absorption performance of -20dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 10.5GHz.

[0070] Example 10

[0071] Step 1: Weigh 4.00g of triethoxysilane (HSi(OC2H5)3) and 3.00g of silicon acetate (Si(CH3COO)4) into a 250mL dry three-necked flask, add 80mL of anhydrous carbon tetrachloride, and treat at 25℃ with magnetic stirring for 0.5 hours until a colorless and transparent solution is formed, which is recorded as solution 1; Separately weigh 7.00g of ethylenediamine (H2NCH2CH2NH2) into a 150mL dry flask, add 100mL of dichloromethane, and treat at 50℃ with mechanical stirring for 1 hour to obtain transparent solution 2; Slowly add solution 2 dropwise to the three-necked flask containing solution 1 through a constant pressure dropping funnel, and treat at 0℃ in air atmosphere with magnetic stirring for 0.5 hours.

[0072] Step 2: Treat the above suspension in an oil bath at 180°C, in an air atmosphere, and with magnetic stirring for 200 hours;

[0073] Step 3: After the reaction is complete, the product is filtered, washed with carbon tetrachloride, and dried at 400℃ for 0.5 hours to obtain a bulk nitrogen-containing inorganic-organosilicon-based hybrid material. The material has a multi-point BET specific surface area of ​​156.34 m². 2 The material exhibits a nitrogen content of 8.3 wt% and a static CO2 adsorption capacity of 2.0 mmol / g, with an average pore size of 10.56 nm. Elemental analysis revealed a static CO2 adsorption capacity of 2.0 mmol / g. -1 The material has a wave absorption performance of -18dB and an effective absorption frequency (R<-10dB, -10dB is equivalent to absorbing 90% of electromagnetic waves) of 8.6GHz.

[0074] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. An inorganic-organosilicon based nitrogen-containing hybrid material that adsorbs CO2 and absorbs electromagnetic waves, characterized by: The structural formula of the material satisfies Si 4+ (NH-R-NH)n, wherein -NH-R-NH- is an organic amine ligand, -R- represents an organic group; n represents the number of organic amine ligands, n = 2-4.

2. The inorganic-organic silicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to claim 1, characterized in that: The inorganic-organic silicon-based nitrogen-containing hybrid material has a nitrogen content of 5.1wt%-16.0wt%, and a CO2 static adsorption capacity of 1.2-5.0mmolg -1 The BET specific surface area is 10.0-600.0m 2 / g, and the adsorption average pore size is 2.0-50.0 nm.

3. The inorganic-organic silicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to claim 1, characterized in that: The inorganic-organic silicon-based nitrogen-containing hybrid material has a wave absorption performance of -25dB to -10dB, and an effective wave absorption frequency of 8.2GHz to 12.1GHz, wherein R<-10dB, and -10dB corresponds to absorption of 90% of electromagnetic waves.

4. A method for preparing the inorganic-organic silicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to any one of claims 1 to 3, characterized by: The method comprises the following steps: Step 1: mixing a silicon source and a solvent to prepare a solution 1; mixing an organic amine and a solvent to prepare a solution 2; and mixing the solution 1 and the solution 2 to obtain a suspension; Step 2: heating the suspension to perform a reaction; Step 3: after the reaction is completed, performing filtration, washing and drying to obtain the inorganic-organic silicon-based nitrogen-containing hybrid material.

5. The method of claim 4, wherein the method further comprises: 5.

1. mixing the inorganic-organic silica-based nitrogen-containing hybrid material with a solvent to form a mixture; 5.

2. heating the mixture to form a solution; and 5.

3. cooling the solution to form the inorganic-organic silica-based nitrogen- containing hybrid material. 5.

4. repeating steps 5.1-5.3 one or more times. The silicon source includes, but is not limited to, any one or combination of the following: tetraethyl orthosilicate, tetramethyl orthosilicate, triethoxysilane, methyl triethoxysilane, silicon carbonate, silicon halide, silicon nitrate and silicon acetate.

6. The method for preparing an inorganic-organosilicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to claim 4, characterized in that: The solvent refers to a solvent capable of dissolving the silicon source and the organic amine ligand, and includes inorganic solvents and organic solvents, and specifically includes water, methanol, ethanol, tetrahydrofuran, pyridine, dichloromethane, carbon tetrachloride, benzene and toluene, and any one of the above solvents or a combination of multiple solvents can be selected.

7. The method of claim 4, wherein the inorganic-organic silicon-based nitrogen-containing hybrid material is prepared by the following steps: (1) mixing a silicon source, a nitrogen source, and a solvent to form a mixture; (2) heating the mixture to form a gel; (3) drying the gel; and (4) calcining the dried gel. The organic amine is any one or combination of the following: ethylenediamine, 1,3-propanediamine, 1,2-propanediamine, 1,6-hexanediamine, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, diethylenetriamine, benzene-1,2,3-triamine and N,N-diethyldiethylenetriamine.

8. The method of claim 4, wherein the method further comprises: 5 heating the mixture to a temperature of about 100°C to about 200°C; and 6 heating the mixture to a temperature of about 400°C to about 600°C. 7 The temperature for mixing in step 1 is 0°C to 50°C.

9. The method for preparing an inorganic-organosilicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to claim 4, characterized in that: The temperature for the heating reaction in step 2 is 100°C to 200°C, and the reaction time is 1h to 216h.

10. The method for preparing an inorganic-organosilicon-based nitrogen-containing hybrid material for adsorbing CO2 and absorbing electromagnetic waves according to claim 4, characterized in that: The drying temperature in step 3 is 120°C to 500°C, and the drying time is 0.5h to 24h.

Images