An advanced oxidation catalyst based on Mn3N2 and its preparation method
By combining low-temperature water bath and hydrothermal synthesis with calcination, a highly dispersed Mn3N2 nanoparticle catalyst with a high specific surface area was prepared, which solved the problems of poor efficiency and complex synthesis of manganese-based catalysts in the prior art, and achieved high efficiency catalytic performance and a simple preparation process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHAANXI UNIV OF SCI & TECH
- Filing Date
- 2024-07-30
- Publication Date
- 2026-05-29
AI Technical Summary
In existing technologies, manganese-based catalysts have poor efficiency, small catalytic activity surface area, and metal ion dissolution problems during the reaction process. Furthermore, the synthesis process of Mn3N2 is complex and relies on large-scale equipment.
Mn3N2 nanoparticles were prepared by adding polyvinylpyrrolidone in batches using a low-temperature water bath pre-coordination and hydrothermal synthesis method. Combined with calcination treatment, a catalyst with high dispersion and high specific surface area was obtained.
It improves the efficiency and catalytic activity of Mn3N2 catalyst, increases the specific surface area, inhibits the dissolution of metal ions, simplifies the synthesis process, and avoids dependence on large-scale equipment.
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Figure CN119076034B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of advanced oxidation catalysis of heterogeneous catalysts, specifically relating to an advanced oxidation catalyst based on Mn3N2 and its preparation method. Background Technology
[0002] Antibiotics play a vital role in human health, but they are absorbed and transformed in organisms, then excreted as metabolites, with some remaining in their original form. Even after treatment, trace residues can still enter the aquatic environment and water cycle, posing a significant threat to human health if consumed in contaminated water long-term. Therefore, thoroughly removing antibiotics from wastewater has become a new challenge. In current research, advanced oxidation processes (AOPs) have attracted considerable attention due to their high degradation rates. This method primarily utilizes the generated reactive oxygen species, such as sulfate radicals (SO4-·), hydroxyl radicals (·OH), and singlet oxygen (…). 1 O2) completes the degradation process of organic matter.
[0003] Transition metals can effectively activate persulfate to degrade antibiotics, offering advantages such as low cost, low energy consumption, and ease of promotion. Compared to manganese oxides, manganese nitrides possess advantages such as variable valence states, flexible electronic structures and electron mobility, and less metal ion leakage. However, research on manganese nitride Mn3N2 in advanced oxidation technologies is relatively rare. Furthermore, common synthesis methods for Mn3N2 include magnetron sputtering, chemical vapor deposition, and metal nitriding, all of which rely on large-scale equipment. More importantly, the products obtained by these methods have relatively smooth surfaces and small specific surface areas, which are not conducive to providing abundant reaction sites and catalytic sites for catalytic reactions. Therefore, designing a simple method for preparing Mn3N2 to increase the specific surface area of the synthesized material is of great significance for enhancing its application value in advanced catalytic oxidation technologies. Summary of the Invention
[0004] The purpose of this invention is to provide an advanced oxidation catalyst based on Mn3N2 and its preparation method, so as to solve the problems of poor efficiency, small catalytic activity specific surface area and metal ion dissolution in the reaction process of existing manganese-based catalysts, while simplifying and optimizing the complex synthesis process of Mn3N2.
[0005] To achieve the above objectives, the present invention employs the following technical solution:
[0006] A method for preparing an advanced oxidation catalyst based on Mn3N2, comprising:
[0007] S1: Solution A is prepared by mixing N,N dimethylformamide with ethanol;
[0008] S2: Add manganese chloride (heated to remove water of crystallization) and polyvinylpyrrolidone to solution A, stir until completely dissolved, and obtain solution B;
[0009] S3: Add 5,10,15,20-tetracarboxyphenylporphyrin to solution B and stir until completely dissolved to obtain solution C. React solution C under water bath heating conditions to obtain liquid D.
[0010] S4: Add polyvinylpyrrolidone to solution D, stir to dissolve, carry out hydrothermal reaction, and after the reaction is completed, centrifuge and dry to collect powder sample E;
[0011] S5: Heat-treat powder sample E in an inert gas atmosphere to obtain Mn3N2.
[0012] Preferably, in S1, N,N dimethylformamide and ethanol are mixed in a volume ratio of 1:3 to 1:1.
[0013] Preferably, in step S2, 0.5 g to 1.0 g of manganese chloride and 10 mg to 20 mg of polyvinylpyrrolidone are dissolved in 40 mL to 70 mL of solvent A and stirred until completely dissolved to obtain solution B.
[0014] Preferably, in step S3, 12 mg to 24 mg of 5,10,15,20-tetracarboxyphenylporphyrin is dissolved in solution B and stirred until completely dissolved to obtain solution C.
[0015] Preferably, in step S3, liquid D is obtained by reacting in a water bath at 50°C to 80°C for 20 to 30 minutes.
[0016] Preferably, in step S4, 10 mg to 20 mg of polyvinylpyrrolidone is added to solution D and stirred to dissolve. Then, a hydrothermal reaction is carried out at 80°C for 18 to 24 hours, followed by centrifugation and drying to obtain powder sample E.
[0017] Preferably, after adding 10 mg to 20 mg of polyvinylpyrrolidone to solution D and stirring to dissolve it, the solution is transferred to a polytetrafluoroethylene liner, sealed and locked in a stainless steel hydrothermal reactor, and subjected to a hydrothermal reaction at 80°C to 100°C for 18 to 24 hours.
[0018] Preferably, in step S5, the powder sample E is placed in a ceramic boat and heat-treated in a tube furnace for 2-3 hours under an inert gas atmosphere to obtain Mn3N2.
[0019] Preferably, in step S5, heat treatment is performed under an argon or nitrogen atmosphere at a temperature of 500°C to 650°C.
[0020] This application also discloses an advanced oxidation catalyst based on Mn3N2, which is prepared by any of the preparation methods described above.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] The method for preparing Mn3N2 provided by this invention involves two steps: low-temperature water bath pre-coordination and hydrothermal synthesis. PVP is added in batches during the low-temperature water bath and hydrothermal stages, respectively protecting the low-dimensional crystal nuclei and preventing nanoparticle growth. Calcination yields a highly dispersed Mn3N2 nanoparticle catalyst with a high specific surface area. The Mn3N2 catalyst prepared by this method exhibits high efficiency, a large catalytically active specific surface area, strong nitrogen atom anchoring effect on manganese ions, and minimal metal ion dissolution. Furthermore, the synthesis of Mn3N2 is simple and easy to perform, without relying on large equipment, avoiding the dependence on large equipment in conventional magnetron sputtering, vapor deposition, and metal nitriding methods. The synthesis method is simpler and safer, and the synthesized Mn3N2 has a larger specific surface area, providing more abundant catalytically active sites.
[0023] The Mn3N2 synthesized in this invention exhibits high electronic mobility, high efficiency in catalyzing the decomposition of PMS to generate active oxygen, and nitrogen atoms can anchor manganese ions, effectively inhibiting the dissolution of manganese ions, improving the reusability of the catalyst, and avoiding secondary pollution. Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 Scanning electron microscope image of Mn3N2;
[0026] Figure 2 The degradation curve of methylene blue catalyzed by Mn3N2. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.
[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0030] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0031] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.
[0032] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.
[0033] The present invention will now be described in further detail with reference to the accompanying drawings:
[0034] The technical solution provided by this invention is: a method for preparing an advanced oxidation catalyst based on Mn3N2, comprising:
[0035] S1: Solution A is prepared by mixing N,N dimethylformamide (DMF) with ethanol;
[0036] S2: Add manganese chloride (after heating to remove water of crystallization) and polyvinylpyrrolidone (PVP) to solution A and stir until completely dissolved to obtain solution B;
[0037] S3: Add 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react under a 60°C water bath to obtain liquid D.
[0038] S4: Add polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal reactor, carry out hydrothermal reaction at 80°C, centrifuge and dry to collect powder sample E.
[0039] S5: The collected powder sample E was then placed in a porcelain boat and heat-treated in a tube furnace under an inert gas atmosphere to obtain Mn3N2.
[0040] In some embodiments, in S1, DMF and ethanol are mixed at a volume ratio of 1:3 to 1:1.
[0041] In some embodiments, in step S2, 0.5 g to 1.0 g of manganese chloride and 10 mg to 20 mg of polyvinylpyrrolidone are dissolved in 40 mL to 70 mL of solvent A and stirred until completely dissolved to obtain solution B.
[0042] In some embodiments, in step S3, 12 mg to 24 mg of 5,10,15,20-tetracarboxyphenylporphyrin is dissolved in solution B and stirred until completely dissolved to obtain solution C. Solution C is then reacted in a water bath at 60°C for 20 to 30 minutes to obtain liquid D.
[0043] In some embodiments, in step S4, 10 mg to 20 mg of polyvinylpyrrolidone (PVP) is added to solution D, stirred and dissolved, then transferred to a polytetrafluoroethylene liner, sealed and locked in a stainless steel hydrothermal autoclave, and subjected to a hydrothermal reaction at 80°C for 18 to 24 hours. The powder sample E is then collected by centrifugation and drying.
[0044] In some embodiments, in step S5, heat treatment is performed under an argon or nitrogen atmosphere at a temperature of 500°C to 650°C for 2 to 3 hours.
[0045] In some embodiments, a method for preparing an advanced oxidation catalyst based on Mn3N2 includes:
[0046] Step 1: Mix N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:3 to 1:1 to prepare solution A;
[0047] Step 2: Add 0.5g to 1.0g of manganese chloride (heated to remove water of crystallization) and 10mg to 20mg of polyvinylpyrrolidone (PVP) to 40mL to 70mL of solution A, and stir until completely dissolved to obtain solution B;
[0048] Step 3: Add 12mg to 24mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B, continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react in a 60°C water bath for 20 to 30 minutes to obtain liquid D.
[0049] Step 4: Add 10 mg to 20 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal reactor, and carry out hydrothermal reaction at 80°C for 18 to 24 hours. Centrifuge and dry to collect powder sample E.
[0050] Step 5: The collected powder sample E is then placed in a porcelain boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 500℃~650℃ for 2~3 hours to obtain Mn3N2.
[0051] Example 1:
[0052] Step 1: Mix N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:3 to prepare solution A;
[0053] Step 2: Add 0.5g of manganese chloride (heated to remove water of crystallization) and 10mg of polyvinylpyrrolidone (PVP) to 40mL of solution A, stir until completely dissolved, and obtain solution B;
[0054] Step 3: Add 12 mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react in a 60°C water bath for 30 minutes to obtain liquid D.
[0055] Step 4: Add 10 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal autoclave, and carry out hydrothermal reaction at 80°C for 18 hours. Centrifuge and dry to collect powder sample E.
[0056] Step 5: The collected powder sample E is then placed in a ceramic boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 600℃ for 2 hours to obtain Mn3N2.
[0057] Example 2:
[0058] Step 1: Mix N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:2 to prepare solution A;
[0059] Step 2: Add 1.0g of manganese chloride (heated to remove water of crystallization) and 20mg of polyvinylpyrrolidone (PVP) to 70mL of solution A, stir until completely dissolved, and obtain solution B;
[0060] Step 3: Add 24 mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react for 20 minutes in a 60°C water bath to obtain liquid D.
[0061] Step 4: Add 20 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal autoclave, and carry out hydrothermal reaction at 80°C for 20 hours. Centrifuge and dry to collect powder sample E.
[0062] Step 5: The collected powder sample E is then placed in a porcelain boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 650°C for 2 hours to obtain Mn3N2.
[0063] Example 3:
[0064] Step 1: Mix N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:2 to prepare solution A;
[0065] Step 2: Add 0.8g of manganese chloride (heated to remove water of crystallization) and 16mg of polyvinylpyrrolidone (PVP) to 60mL of solution A, stir until completely dissolved, and obtain solution B;
[0066] Step 3: Add 20 mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react for 25 minutes in a 70°C water bath to obtain liquid D.
[0067] Step 4: Add 16 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal autoclave, and carry out hydrothermal reaction at 85°C for 18 hours. Centrifuge and dry to collect powder sample E.
[0068] Step 5: The collected powder sample E is then placed in a ceramic boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 600℃ for 2.5 hours to obtain Mn3N2.
[0069] Example 4:
[0070] Step 1: Prepare solution A by mixing N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:1.5;
[0071] Step 2: Add 0.6g of manganese chloride (heated to remove water of crystallization) and 12mg of polyvinylpyrrolidone (PVP) to 45mL of solution A, stir until completely dissolved, and obtain solution B;
[0072] Step 3: Add 15 mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react in a water bath at 65°C for 30 minutes to obtain liquid D.
[0073] Step 4: Add 14 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal autoclave, and carry out hydrothermal reaction at 90°C for 22 hours. Centrifuge and dry to collect powder sample E.
[0074] Step 5: The collected powder sample E is then placed in a ceramic boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 500°C for 3 hours to obtain Mn3N2.
[0075] Example 5:
[0076] Step 1: Mix N,N dimethylformamide (DMF) and ethanol at a volume ratio of 1:1 to prepare solution A;
[0077] Step 2: Add 0.9g of manganese chloride (heated to remove water of crystallization) and 18mg of polyvinylpyrrolidone (PVP) to 65mL of solution A, and stir until completely dissolved to obtain solution B;
[0078] Step 3: Add 20 mg of 5,10,15,20-tetracarboxyphenylporphyrin (TCPP) to solution B and continue magnetic stirring until the drug is completely dissolved to obtain solution C. Transfer solution C to a distillation flask and react for 20 minutes in an 80°C water bath to obtain liquid D.
[0079] Step 4: Add 20 mg of polyvinylpyrrolidone (PVP) to solution D, stir to dissolve, transfer to a polytetrafluoroethylene liner, seal and lock in a stainless steel hydrothermal reactor, and carry out hydrothermal reaction at 100°C for 20 hours. Centrifuge and dry to collect powder sample E.
[0080] Step 5: The collected powder sample E is then placed in a porcelain boat and heat-treated in a tube furnace under an argon or nitrogen atmosphere at a temperature of 580°C for 3 hours to obtain Mn3N2.
[0081] Figure 1 The scanning electron microscope image of Mn3N2 with high specific surface area shows that the prepared Mn3N2 is composed of nanoparticles with large specific surface area and has a rich pore structure, which further increases the interaction sites between the Mn3N2 catalyst and persulfate.
[0082] The performance of Mn3N2 as a catalyst for the degradation of methylene blue by PMS was evaluated. Figure 2 The results show that, under the action of Mn3N2, 99.9% of methylene blue can be efficiently degraded within 20 minutes, indicating that Mn3N2 has excellent catalytic performance.
[0083] In summary, this invention discloses an advanced oxidation catalyst based on Mn3N2 and its preparation method. The precursor synthesis is completed in two steps: low-temperature water bath pre-coordination and hydrothermal synthesis. PVP is added in batches during the low-temperature water bath and hydrothermal stages, respectively protecting the low-dimensional crystal nuclei and preventing the growth of nanoparticles. Calcination yields a Mn3N2 nanoparticle catalyst with high dispersion and high specific surface area. The Mn3N2 catalyst prepared by this method exhibits high efficiency, large catalytic activity, and a strong anchoring effect of nitrogen atoms on manganese ions, making it difficult for metal ions to dissolve. Furthermore, the synthesis of Mn3N2 does not rely on large-scale equipment and is simple and easy to perform.
[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing an advanced oxidation catalyst based on Mn3N2, characterized in that, include: S1: Solution A is prepared by mixing N,N-dimethylformamide with ethanol; S2: Add manganese chloride (heated to remove water of crystallization) and polyvinylpyrrolidone to solution A, stir until completely dissolved, and obtain solution B; S3: Add 5,10,15,20-tetracarboxyphenylporphyrin to solution B and stir until completely dissolved to obtain solution C. React solution C in a water bath at 50 ℃~80 ℃ for 20~30 minutes to obtain solution D. S4: Add polyvinylpyrrolidone to solution D, stir to dissolve, and then carry out a hydrothermal reaction at 80 °C for 18-24 hours. After centrifugation and drying, collect the powder sample E. S5: Heat-treat powder sample E in an argon or nitrogen atmosphere at a temperature of 500℃~650℃ to obtain Mn3N2.
2. The method for preparing an advanced oxidation catalyst based on Mn3N2 according to claim 1, characterized in that, In S1, N,N-dimethylformamide and ethanol are mixed in a volume ratio of 1:3 to 1:
1.
3. The method for preparing an advanced oxidation catalyst based on Mn3N2 according to claim 1, characterized in that, In step S2, 0.5 g to 1.0 g of manganese chloride and 10 mg to 20 mg of polyvinylpyrrolidone are dissolved in 40 mL to 70 mL of solution A and stirred until completely dissolved to obtain solution B.
4. The method for preparing an advanced oxidation catalyst based on Mn3N2 according to claim 1, characterized in that, In step S3, 12 mg to 24 mg of 5,10,15,20-tetracarboxyphenylporphyrin is dissolved in solution B and stirred until completely dissolved to obtain solution C.
5. The method for preparing an advanced oxidation catalyst based on Mn3N2 according to claim 1, characterized in that, In step S4, 10 mg to 20 mg of polyvinylpyrrolidone is added to solution D and stirred until dissolved.
6. The method for preparing an advanced oxidation catalyst based on Mn3N2 according to claim 1, characterized in that, In step S5, powder sample E is placed in a ceramic boat and heat-treated in a tube furnace for 2-3 hours under an argon or nitrogen atmosphere to obtain Mn3N2.
7. An advanced oxidation catalyst based on Mn3N2, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.