Acetic acid modified inorganic composite gel material and preparation method thereof

Abstract

This invention discloses an acetic acid-modified inorganic composite gel material and its preparation method, belonging to the field of organic material synthesis technology. The acetic acid-modified inorganic composite gel material comprises the following materials in parts by weight: 0.2-0.4 parts of acetic acid-Co3O4, 1.5-2.5 parts of acrylamide, 1-1.5 parts of glycerol, 0.05-0.1 parts of N-N-dimethylformamide, 0.25-0.5 parts of ammonium persulfate, 0.1-0.15 parts of sulfonated-Bi2O3, 0.6-0.9 parts of ethylenediamine, and 0.2-0.4 parts of PVP; the acetic acid-Co3O4 comprises materials in the following mass ratio: acetic acid:cobalt nitrate:thiourea:ammonium fluoride:sodium bicarbonate = 3-7:1.5-2.5:0.8-1.2:0.5-1:6; the sulfonated-Bi2O3 comprises materials in the following mass ratio: Bi2O3:sodium sulfite:H2O2:ammonium bicarbonate = 3-5:0.2-0.6:1-1.5:1. This material achieves efficient and stable catalysis for nitrogen reduction under mild conditions through structural defect regulation, interfacial functional group modification, heterojunction electronic regulation, and synergistic enhancement with organic gel.

Description

Technical Field

[0001] This invention belongs to the field of organic material synthesis technology, specifically relating to an acetic acid-modified inorganic composite gel material and its preparation method. Background Technology

[0002] Ambient temperature and pressure catalytic nitrogen reduction for ammonia synthesis offers advantages such as being green, low-carbon, and having mild reaction conditions, making it an important research direction for replacing traditional high-energy-consuming and high-polluting industrial ammonia synthesis processes. Among these, Bi₂O₃ exhibits good application potential in nitrogen reduction catalysis due to its suitable band structure, low cost, and environmental friendliness. However, pure-phase Bi₂O₃ suffers from drawbacks such as small specific surface area, lack of pore structure, insufficient surface active sites, weak nitrogen adsorption activation ability, high carrier recombination efficiency, and slow catalytic reaction kinetics, which significantly limit its catalytic performance.

[0003] Currently, single-structure modification or surface modification methods have limited effect on improving the performance of Bi2O3. Conventional bimetallic composite systems suffer from problems such as loose interfacial bonding, high charge transfer impedance, and poor synergistic catalytic effect. At the same time, traditional inorganic powder catalysts generally suffer from drawbacks such as easy agglomeration, easy shedding of active components, poor cycle stability, and difficulty in recycling and reuse. Furthermore, it is difficult to construct a stable catalytic microenvironment, which makes it impossible to continuously and efficiently promote the nitrogen reduction reaction. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide an acetic acid-modified inorganic composite gel material and its preparation method, which achieves efficient and stable catalysis of nitrogen reduction under mild conditions through structural defect regulation, interfacial functional group modification, heterojunction electronic regulation and synergistic effect of organic gel.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention provides an acetic acid-modified inorganic composite gel material, which comprises the following materials in parts by weight: 0.2-0.4 parts of acetic acid-Co3O4, 1.5-2.5 parts of acrylamide, 1-1.5 parts of glycerol, 0.05-0.1 parts of N,N-dimethylformamide, 0.25-0.5 parts of ammonium persulfate, 0.1-0.15 parts of sulfonated Bi2O3, 0.6-0.9 parts of ethylenediamine, and 0.2-0.4 parts of PVP; The acetic acid-Co3O4 comprises materials in the following mass ratio: acetic acid: cobalt nitrate: thiourea: ammonium fluoride: sodium bicarbonate = 3-7: 1.5-2.5: 0.8-1.2: 0.5-1: 6; The sulfonated-Bi2O3 comprises materials in the following mass ratio: Bi2O3:sodium sulfite:H2O2:ammonium bicarbonate = 3-5:0.2-0.6:1-1.5:1.

[0006] Furthermore, the preparation method of the sulfonated-Bi2O3 includes the following steps: S11, weigh 3-5 parts Bi2O3 and 1 part ammonium bicarbonate and grind them in a grinding mill for 30 min, then calcine them at a temperature of 500-600℃ for 2-4 h, and sieve them using a 200 mesh screen to obtain pretreated Bi2O3. S12, weigh 0.2-0.6 parts of sodium sulfite and add it to 15 parts of deionized water. Stir at 500 r / min and heat at 70-90℃ for 30 min. Add the pretreated Bi2O3 obtained in step S11 and raise the temperature to 120℃ and reflux for 1.5-2.5 h. Filter the mixture using a 0.45 micron filter membrane to obtain modified Bi2O3. S13, add the modified Bi2O3 obtained in step S12 to 50 parts of deionized water, stir for 30 min at a speed of 500 r / min, weigh 1-1.5 parts of H2O2 and add it to the mixture, heat and reflux at 90℃ for 1-2 h, wash with deionized water and anhydrous ethanol alternately 3 times each, and dry at 65℃ for 24 h to obtain sulfonated Bi2O3.

[0007] Furthermore, the method for preparing acetylated Co3O4 includes the following steps: S21, weigh 1.5-2.5 parts of cobalt nitrate and add them to 50 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.8-1.2 parts of thiourea and 0.5-1 parts of ammonium fluoride and add them to the mixture. Continue stirring at the above speed for 30 min. Heat at 110-150℃ for 6-12 h. Wash with deionized water and anhydrous ethanol three times each to obtain MOF-Co. S22, weigh 6 parts of sodium bicarbonate and add it to the MOF-Co obtained in step S21. Grind it with a grinding wheel for 15 min and calcine it at a temperature of 400-550℃ for 2-4 h to obtain Co3O4. S23, add the Co3O4 obtained in step S22 to 200 parts of deionized water, stir at 500 r / min for 30 min, weigh 3-7 parts of glacial acetic acid and add it, continue stirring at the above speed, and reflux at 90-130℃ for 12 h, wash with deionized water and anhydrous ethanol alternately 3 times each to obtain acetylated-Co3O4.

[0008] This invention also provides a method for preparing an acetic acid-modified inorganic composite gel material, comprising the following steps: S31, weigh 0.2-0.4 parts of PVP and add them to 30 parts of deionized water, stir at 500 r / min for 30 min, weigh 0.2-0.4 parts of acetate-Co3O4 and 0.1-0.15 parts of sulfonated-Bi2O3 and add them to the mixture, sonicate at 25 kHz for 20-30 min, and continue stirring at the above speed for 30 min to obtain an inorganic dispersion; S32, weigh 1.5-2.5 parts acrylamide, 1-1.5 parts glycerol and 0.6-0.9 parts ethylenediamine and add them to 100 parts deionized water. Stir at 500 r / min for 60 min and introduce nitrogen gas at a flow rate of 100 mL / min to obtain the prepolymer solution. S33, add the prepolymer obtained in step S32 to the inorganic dispersion obtained in step S31, and stir at 500 r / min for 30 min. Weigh 0.05-0.1 parts of N,N dimethylformamide and 0.25-0.5 parts of ammonium persulfate and add them to 5 parts of deionized water. Stir at 500 r / min for 30 min to obtain the initiating solution. Add the obtained initiating solution to the mixture and continue stirring at the above speed for 30 min. Heat at 70-110℃ for 2-4 h, and then mature at 60℃ for 12 h to obtain the acetic acid modified inorganic composite gel material.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The acetic acid-modified inorganic composite gel material prepared in this invention uses Bi₂O₃ as the base material. Through ammonium bicarbonate-assisted calcination, a hierarchical porous structure and oxygen vacancy defects are constructed in the Bi₂O₃ lattice, increasing the specific surface area of ​​the material while simultaneously building a large number of charge-enriched active sites, thereby improving the specific surface area and adsorption sites of Bi₂O₃. Furthermore, sulfonation modification introduces abundant -SO₃H functional groups onto the Bi₂O₃ surface, utilizing hydrogen bonds to alter the surface adsorption properties, enhancing the catalyst's adsorption and enrichment capacity for nitrogen molecules and improving interfacial activation efficiency, thus providing sufficient substrate for subsequent nitrogen reduction reactions.

[0010] The acetic acid-modified inorganic composite gel material prepared in this invention constructs a heterogeneous catalytic system by incorporating sulfonated Bi₂O₃ with acetic acid-modified Co₃O₄. The electronic regulation effect of the acetate ligand optimizes the electronic structure of the Co active sites, lowers the energy barrier of the nitrogen reduction reaction, and enhances the intrinsic catalytic reduction activity. Simultaneously, the -SO₃H groups on the surface of sulfonated Bi₂O₃ and the -COOH groups on the surface of acetic acid-modified Co₃O₄ can form multiple hydrogen bonds, resulting in a tight interface between the two oxides. This effectively reduces the interfacial charge transfer impedance, constructs a highly efficient interphase electron transport channel, significantly promotes the rapid separation and directional migration of charge carriers at the interface, and suppresses the loss of charge carriers through bulk recombination, thereby greatly improving the catalytic reaction efficiency from a kinetic perspective.

[0011] The acetic acid-modified inorganic composite gel material prepared in this invention introduces an acrylamide-ethylenediamine crosslinked gel as an organic substrate to construct an organic-inorganic synergistic composite catalytic system. The stable, water-rich microenvironment constructed by the gel system can continuously provide a sufficient proton source for the proton-coupled electron transfer process of the nitrogen reduction reaction, ensuring the continuous forward progress of the reduction reaction. Nitrogen gas is introduced before polymerization to effectively remove dissolved oxygen from the system, avoiding monomer oxidation side reactions and ensuring the purity and uniformity of the polymerization network. At the same time, the amino groups on the surface of the gel framework can form hydrogen bonds with the acetate groups on the surface of acetic acidified Co3O4, achieving orderly and compact composite of bimetallic oxide nanoparticles, effectively inhibiting inorganic particle aggregation and interfacial delamination. The steric stabilization effect of PVP and the plasticizing and water-retaining effect of glycerol synergistically improve the dispersion uniformity of inorganic particles in the gel network, enhance the structural stability and mechanical properties of the gel system, and optimize the microenvironment of the catalytic reaction. In addition, the amino groups on the gel surface can serve as auxiliary active sites to participate in the adsorption and activation of N2 molecules, and together with defective Bi2O3 and electronically regulated Co3O4, they can form a multi-center synergistic catalytic system. The three-dimensional framework of the gel provides a dual fixation effect of physical encapsulation and chemical anchoring of inorganic nanoparticles, giving the composite material excellent cycle stability and convenient recyclability, effectively solving the technical defects of traditional powder catalysts that are easy to agglomerate and difficult to separate. Attached Figure Description

[0012] Figure 1 This is a simplified diagram of the preparation method of the acetic acid-modified inorganic composite gel material proposed in this application; Figure 2 The NH4+ of the acetic acid-modified inorganic composite gel materials prepared for the examples and comparative examples 4+ Image showing the results of ion testing. Detailed Implementation

[0013] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0014] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0015] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0016] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0017] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0018] This invention provides an acetic acid-modified inorganic composite gel material and its preparation method.

[0019] First, Bi₂O₃ is modified by ammonium bicarbonate-assisted calcination. This constructs a hierarchical porous structure and oxygen vacancy defects, effectively increasing the specific surface area and enriching active sites. Sulfonation modification introduces -SO₃H functional groups onto the Bi₂O₃ surface, optimizing surface properties through hydrogen bonding and significantly enhancing nitrogen adsorption and activation capabilities. Further, co-acetylated Co₃O₄ is composited to construct a heterojunction. Acetyl groups regulate the electronic structure of active sites, lowering the reaction energy barrier. Simultaneously, interfacial hydrogen bonds effectively reduce charge transfer impedance, accelerating carrier transport and inhibiting recombination. This invention introduces a polyacrylamide-ethylenediamine crosslinked gel as a support, synergistically combining PVP and glycerol to optimize the microscopic reaction environment, constructing a multi-center synergistic catalytic system. This significantly improves the problems of easy agglomeration and difficult recovery of powder catalysts, achieving efficient and stable nitrogen reduction catalysis under mild conditions.

[0020] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0021] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0022] Example 1 like Figure 1 As shown, an acetic acid-modified inorganic composite gel material comprises the following parts by weight: 0.2 parts of acetic acid-Co3O4, 1.5 parts of acrylamide, 1 part of glycerol, 0.05 parts of N,N-dimethylformamide, 0.25 parts of ammonium persulfate, 0.1 parts of sulfonated Bi2O3, 0.6 parts of ethylenediamine, and 0.2 parts of PVP; The preparation method of the sulfonated-Bi2O3 includes the following steps: S11. Weigh 3 parts Bi2O3 and 1 part ammonium bicarbonate and grind them in a grinding mill for 30 min. Then, calcine them at 500℃ for 2 h and sieve them using a 200-mesh screen to obtain pretreated Bi2O3. S12. Weigh 0.2 parts of sodium sulfite and add it to 15 parts of deionized water. Stir at 500 r / min and heat at 70℃ for 30 min. Add the pretreated Bi2O3 obtained in step S11 and raise the temperature to 120℃ and reflux for 1.5 h. Filter the mixture using a 0.45 micron filter membrane to obtain modified Bi2O3. S13. Add the modified Bi2O3 obtained in step S12 to 50 parts of deionized water and stir for 30 min at a speed of 500 r / min. Weigh 1 part of H2O2 and add it to the mixture. Heat and reflux at 90℃ for 1 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Dry the mixture at 65℃ for 24 h to obtain sulfonated Bi2O3.

[0023] The method for preparing acetylated Co3O4 includes the following steps: S21. Weigh 1.5 parts of cobalt nitrate and add them to 50 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.8 parts of thiourea and 0.5 parts of ammonium fluoride and add them to the mixture. Continue stirring at the same speed for 30 min. Heat at 110℃ for 6 h. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain MOF-Co. S22. Weigh 6 parts of sodium bicarbonate and add it to the MOF-Co obtained in step S21. Grind it with a grinding wheel for 15 min and calcine it at 400℃ for 2 h to obtain Co3O4. S23. Add the Co3O4 obtained in step S22 to 200 parts of deionized water and stir for 30 minutes at a speed of 500 r / min. Weigh 3 parts of glacial acetic acid and add it to the mixture. Continue stirring at the speed mentioned above and reflux at a temperature of 90℃ for 12 hours. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain acetylated-Co3O4.

[0024] This embodiment also provides a method for preparing an acetic acid-modified inorganic composite gel material, comprising the following steps: S31. Weigh 0.2 parts of PVP and add them to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.2 parts of acetylated-Co3O4 and 0.1 parts of sulfonated-Bi2O3 and add them to the mixture. Sonicate at 25 kHz for 20-30 min. Continue stirring at the above speed for 30 min to obtain an inorganic dispersion. S32. Weigh 1.5 parts acrylamide, 1 part glycerol and 0.6-0.9 parts ethylenediamine and add them to 100 parts deionized water. Stir at 500 r / min for 60 min and introduce nitrogen gas at a flow rate of 100 mL / min to obtain a prepolymer solution. S33. Add the prepolymer obtained in step S32 to the inorganic dispersion obtained in step S31, and stir for 30 min at a speed of 500 r / min. Weigh 0.05 parts of N,N dimethylformamide and 0.25 parts of ammonium persulfate and add them to 5 parts of deionized water. Stir for 30 min at a speed of 500 r / min to obtain an initiating solution. Add the obtained initiating solution to the mixture and continue stirring at the above speed for 30 min. Heat at a temperature of 70°C for 2 h, and then mature at a temperature of 60°C for 12 h to obtain an acetic acid-modified inorganic composite gel material.

[0025] Example 2 like Figure 1As shown, an acetic acid-modified inorganic composite gel material comprises the following parts by weight: 0.3 parts of acetic acid-Co3O4, 2 parts of acrylamide, 1.3 parts of glycerol, 0.08 parts of N,N-dimethylformamide, 0.4 parts of ammonium persulfate, 0.13 parts of sulfonated Bi2O3, 0.8 parts of ethylenediamine, and 0.3 parts of PVP; The preparation method of sulfonated Bi2O3 includes the following steps: S11. Weigh 4 parts Bi2O3 and 1 part ammonium bicarbonate and grind them in a grinding mill for 30 min. Then, calcine them at 550℃ for 3 h and sieve them using a 200-mesh screen to obtain pretreated Bi2O3. S12. Weigh 0.4 parts of sodium sulfite and add it to 15 parts of deionized water. Stir at 500 r / min and heat at 80℃ for 30 min. Add the pretreated Bi2O3 obtained in step S11 and raise the temperature to 120℃ and reflux for 2 h. Filter the mixture using a 0.45 micron filter membrane to obtain modified Bi2O3. S13. Add the modified Bi2O3 obtained in step S12 to 50 parts of deionized water and stir for 30 min at a speed of 500 r / min. Weigh 1.3 parts of H2O2 and add it to the mixture. Heat and reflux at 90℃ for 1.5 h. Wash the mixture three times each with deionized water and anhydrous ethanol, and dry it at 65℃ for 24 h to obtain sulfonated Bi2O3.

[0026] The method for preparing acetylated Co3O4 includes the following steps: S21. Weigh 2 parts of cobalt nitrate and add them to 50 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 1 part of thiourea and 0.8 parts of ammonium fluoride and add them to the mixture. Continue stirring at the same speed for 30 min. Heat at 130℃ for 9 h. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain MOF-Co. S22. Weigh 6 parts of sodium bicarbonate and add it to the MOF-Co obtained in step S21. Grind it with a grinding wheel for 15 min and calcine it at a temperature of 480℃ for 3 h to obtain Co3O4. S23. Add the Co3O4 obtained in step S22 to 200 parts of deionized water and stir for 30 minutes at a speed of 500 r / min. Weigh 5 parts of glacial acetic acid and add it to the mixture. Continue stirring at the speed mentioned above and reflux at a temperature of 110℃ for 12 hours. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain acetylated-Co3O4.

[0027] This embodiment also provides a method for preparing an acetic acid-modified inorganic composite gel material, comprising the following steps: S31. Weigh 0.3 parts of PVP and add it to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.3 parts of acetate-Co3O4 and 0.13 parts of sulfonated-Bi2O3 and add them to the mixture. Sonicate at 25 kHz for 20-30 min. Continue stirring at the above speed for 30 min to obtain an inorganic dispersion. S32. Weigh 2 parts acrylamide, 1.3 parts glycerol and 0.8 parts ethylenediamine and add them to 100 parts deionized water. Stir at 500 r / min for 60 min and introduce nitrogen gas at a flow rate of 100 mL / min to obtain a prepolymer solution. S33. Add the prepolymer obtained in step S32 to the inorganic dispersion obtained in step S31, and stir for 30 min at a speed of 500 r / min. Weigh 0.08 parts of N,N dimethylformamide and 0.4 parts of ammonium persulfate and add them to 5 parts of deionized water. Stir for 30 min at a speed of 500 r / min to obtain an initiating solution. Add the obtained initiating solution to the mixture and continue stirring at the above speed for 30 min. Heat at a temperature of 90°C for 3 h, and then mature at a temperature of 60°C for 12 h to obtain acetic acid modified inorganic composite gel material.

[0028] Example 3 An acetic acid-modified inorganic composite gel material comprises the following parts by weight: 0.4 parts of acetic acid-Co3O4, 2.5 parts of acrylamide, 1.5 parts of glycerol, 0.1 parts of N,N-dimethylformamide, 0.5 parts of ammonium persulfate, 0.15 parts of sulfonated Bi2O3, 0.9 parts of ethylenediamine, and 0.4 parts of PVP; The preparation method of sulfonated Bi2O3 includes the following steps: S11. Weigh 5 parts Bi2O3 and 1 part ammonium bicarbonate and grind them in a grinding mill for 30 min. Then, calcine them at 600℃ for 4 h and sieve them using a 200-mesh screen to obtain pretreated Bi2O3. S12. Weigh 0.6 parts of sodium sulfite and add it to 15 parts of deionized water. Stir at 500 r / min and heat at 90℃ for 30 min. Add the pretreated Bi2O3 obtained in step S11 and raise the temperature to 120℃ and reflux for 2.5 h. Filter the mixture using a 0.45 micron filter membrane to obtain modified Bi2O3. S13. Add the modified Bi2O3 obtained in step S12 to 50 parts of deionized water and stir for 30 min at a speed of 500 r / min. Weigh 1.5 parts of H2O2 and add it to the mixture. Heat and reflux at 90℃ for 2 h. Wash the mixture three times each with deionized water and anhydrous ethanol. Dry the mixture at 65℃ for 24 h to obtain sulfonated Bi2O3.

[0029] The method for preparing acetylated Co3O4 includes the following steps: S21. Weigh 2.5 parts of cobalt nitrate and add them to 50 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 1.2 parts of thiourea and 1 part of ammonium fluoride and add them to the mixture. Continue stirring at the same speed for 30 min. Heat at 150℃ for 12 h. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain MOF-Co. S22. Weigh 6 parts of sodium bicarbonate and add it to the MOF-Co obtained in step S21. Grind it with a grinding wheel for 15 min and calcine it at a temperature of 550℃ for 4 h to obtain Co3O4. S23. Add the Co3O4 obtained in step S22 to 200 parts of deionized water and stir for 30 minutes at a speed of 500 r / min. Weigh 7 parts of glacial acetic acid and add it to the mixture. Continue stirring at the speed mentioned above and reflux at a temperature of 130℃ for 12 hours. Wash the mixture three times each with deionized water and anhydrous ethanol to obtain acetylated-Co3O4.

[0030] This embodiment also provides a method for preparing an acetic acid-modified inorganic composite gel material, comprising the following steps: S31. Weigh 0.4 parts of PVP and add it to 30 parts of deionized water. Stir at 500 r / min for 30 min. Weigh 0.4 parts of acetate-Co3O4 and 0.15 parts of sulfonated-Bi2O3 and add them to the mixture. Sonicate at 25 kHz for 30 min. Continue stirring at the above speed for 30 min to obtain an inorganic dispersion. S32. Weigh 2.5 parts acrylamide, 1.5 parts glycerol and 0.9 parts ethylenediamine and add them to 100 parts deionized water. Stir at 500 r / min for 60 min and introduce nitrogen gas at a flow rate of 100 mL / min to obtain a prepolymer solution. S33. Add the prepolymer obtained in step S32 to the inorganic dispersion obtained in step S31, and stir for 30 min at a speed of 500 r / min. Weigh 0.1 parts of N,N dimethylformamide and 0.5 parts of ammonium persulfate and add them to 5 parts of deionized water. Stir for 30 min at a speed of 500 r / min to obtain an initiating solution. Add the obtained initiating solution to the mixture and continue stirring at the above speed for 30 min. Heat at a temperature of 110°C for 4 h, and then mature at a temperature of 60°C for 12 h to obtain acetic acid modified inorganic composite gel material.

[0031] Comparative example: The difference between Comparative Example 1 and Example 2 is that acetylated-Co3O4 and sulfonated-Bi2O3 were not added; otherwise, they are the same as in Example 2.

[0032] The difference between Comparative Example 2 and Example 2 is the addition of Co3O4 and Bi2O3, while the rest are the same as Example 2.

[0033] The difference between Comparative Example 3 and Example 2 is that unmodified Co3O4 was added.

[0034] The difference between Comparative Example 4 and Example 2 is that unmodified Bi2O3 was added.

[0035] The nitrogen reduction performance of the prepared acetic acid-modified inorganic composite gel material was tested, and the results are as follows: Figure 2 As shown, NH in Example 2 4+ The concentration reached 6.24 μmol·g -1 ·h -1 Higher than the comparative NH 4+ The concentration indicates that the modification significantly improved the nitrogen reduction performance of Co3O4 and Bi2O3.

[0036] In summary, this invention provides an acetic acid-modified inorganic composite gel material and its preparation method. Using Bi₂O₃ as the matrix, a porous structure with oxygen vacancies is constructed through ammonium bicarbonate-assisted calcination, enriching the catalytic active sites. Sulfonation modification introduces -SO₃H functional groups, regulating interfacial acidity and electric field, and enhancing nitrogen adsorption activation. A heterogeneous structure is constructed using composite acetylated Co₃O₄, leveraging acetate groups to regulate the electronic structure of active sites, lowering the reaction energy barrier, and simultaneously accelerating charge migration and inhibiting carrier recombination through interfacial hydrogen bonding. A stable, water-rich catalytic microenvironment is constructed based on a polyacrylamide-ethylenediamine crosslinked gel, achieving uniform dispersion of the bimetallic oxide and forming a multi-center synergistic catalytic system. This effectively improves the defects of powder catalysts, such as easy agglomeration and difficulty in recovery, achieving efficient and stable nitrogen reduction catalysis under mild conditions.

[0037] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. An acetic acid-modified inorganic composite gel material, characterized in that, The acetic acid-modified inorganic composite gel material comprises the following materials in parts by weight: Acetic acidified Co3O4 0.2-0.4 parts, acrylamide 1.5-2.5 parts, glycerol 1-1.5 parts, NN dimethylformamide 0.05-0.1 parts, ammonium persulfate 0.25-0.5 parts, sulfonated Bi2O3 0.1-0.15 parts, ethylenediamine 0.6-0.9 parts, and PVP 0.2-0.4 parts; The acetic acid-Co3O4 comprises materials in the following mass ratio: acetic acid: cobalt nitrate: thiourea: ammonium fluoride: sodium bicarbonate = 3-7: 1.5-2.5: 0.8-1.2: 0.5-1: 6; The sulfonated-Bi2O3 comprises materials in the following mass ratio: Bi2O3:sodium sulfite:H2O2:ammonium bicarbonate = 3-5:0.2-0.6:1-1.5:

1.

2. The acetic acid-modified inorganic composite gel material according to claim 1, characterized in that, The sulfonated-Bi2O3 was prepared by the following method: S11, Bi2O3 and ammonium bicarbonate are ground, calcined and sieved to obtain pretreated Bi2O3; S12, Sodium sulfite is added to water, stirred, heated, pretreated Bi2O3 is added, refluxed, filtered, and modified Bi2O3 is obtained; S13, add modified Bi2O3 to water, stir, then add H2O2. Heating and washing yields sulfonated Bi2O3.

3. The acetic acid-modified inorganic composite gel material according to claim 2, characterized in that, In S11, the calcination temperature is 500-600℃, and the calcination time is 2-4 hours. In S12, the heating temperature is 70-90℃, the reflux temperature is 120℃, and the reflux time is 1.5-2.5h. In S13, the heating temperature is 90°C, and the heating time is 1-2 hours.

4. The acetic acid-modified inorganic composite gel material according to claim 1, characterized in that, The acetylated-Co3O4 was prepared by the following method: S21, add cobalt nitrate to water and stir, then add thiourea and ammonium fluoride, stir, heat, and wash to obtain MOF-Co; S22, Sodium bicarbonate is added to MOF-Co, ground, and calcined to obtain Co3O4; S23, Co3O4 is added to water and stirred. Acetic acid is added, stirred, and washed to obtain acetic-Co3O4.

5. The acetic acid-modified inorganic composite gel material according to claim 4, characterized in that, In S21, the heating temperature is 110-150℃, and the heating time is 6-12 hours. In S22, the calcination temperature is 400-550℃, and the calcination time is 2-4 hours.

6. A method for preparing an acetic acid-modified inorganic composite gel material according to any one of claims 1 to 5, characterized in that, Includes the following steps: S31, PVP is added to water and stirred. Acetyl-Co3O4 and sulfonated-Bi2O3 are added, ultrasonicated, and stirred to obtain an inorganic dispersion. S32, add acrylamide, glycerol and ethylenediamine to water, stir, and aerate to obtain a prepolymer solution; S33, add the prepolymer to the inorganic dispersion and stir. Add N,N dimethylformamide and ammonium persulfate to water and stir to obtain the initiator. Add the initiator, stir, heat, and mature to obtain the acetic acid-modified inorganic composite gel material.

7. The method for preparing an acetic acid-modified inorganic composite gel material according to claim 6, characterized in that, In S31, the mass ratio of PVP to water is 0.2-0.4:30; In S31, the frequency of the ultrasound is 25 kHz, and the duration of the ultrasound is 20-30 minutes.

8. The method for preparing an acetic acid-modified inorganic composite gel material according to claim 6, characterized in that, In S32, the mass ratio of acrylamide, glycerol, ethylenediamine, and water is 1.5-2.5:1-1.5:0.6-0.9:100; In S32, the gas used for ventilation is nitrogen, and the flow rate of the nitrogen gas is 100 mL / min.

9. The method for preparing an acetic acid-modified inorganic composite gel material according to claim 6, characterized in that, In S33, the heating temperature is 70-110℃, and the heating time is 2-4 hours.

10. The method for preparing an acetic acid-modified inorganic composite gel material according to claim 6, characterized in that, In S33, the aging temperature is 60°C and the aging time is 12 hours.

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