A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, its preparation method and applications

Abstract

The present invention discloses a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, its preparation method and application. The preparation of the Ti–Ni dual-atom dispersed copolymer is as follows: at normal temperature and pressure, monomer one with an aldehyde group and monomer two with an amino group and a triazine ring structure are dispersed in an organic mixed solvent, and then transferred to an oven for solvothermal reaction to form a carbonitride copolymer substrate with an obvious layered structure. Subsequently, through two-stage rotary evaporation and high-temperature calcination, Ti and Ni atoms are dispersed on the copolymer substrate to form a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, which can effectively degrade organic pollutants under visible light. The Ti–Ni dual-atom dispersed copolymer prepared by the present invention has a stable structure, a high single-atom metal loading amount, low raw material costs, and remarkable effects. At the same time, it can achieve directional delocalization regulation of electrons between the two metals and can be used in the fields of heterogeneous catalysis, pollutant degradation, and environmental remediation, etc.

Description

Technical Field

[0001] The present invention belongs to the fields of material preparation and energy environment, and particularly relates to a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, a preparation method thereof, and an application thereof. Background Art

[0002] Emerging organic pollutants (EOPs) mainly come from human activities and are released from pharmaceuticals, plasticizers, cosmetics, endocrine disruptors, pesticides, surfactants, flame retardants, and industrial additives. They are easily released into the environment through volatilization and wastewater discharge. EOPs have high toxicity, carcinogenicity, and bioaccumulation ability, and even at trace concentration levels, they can cause corresponding ecological risks and threaten human health. Therefore, the US Environmental Protection Agency (EPA) has listed most EOPs as priority pollutants. Researchers have proposed various physical, chemical, and biological methods to remove EOPs from the environment. However, inefficient and incomplete oxidation usually results in the production of toxic intermediate products of EOPs. Therefore, a highly efficient and environmentally friendly technology is needed to completely remove EOPs.

[0003] Photocatalytic oxidation is a promising technology for removing persistent pollutants. This technology generates highly active free radicals through photoexcitation and can degrade and mineralize most organic pollutants. However, most current photocatalysts have problems such as a narrow light response range, a high recombination rate of photo-generated electrons and holes, and poor photocatalytic activity and selectivity. Atomically dispersed catalysts (ADCs) are one of the research hotspots in heterogeneous catalysis. Since ADC catalysts have the highest atomic utilization rate, unique electronic structures, and an unsaturated coordination environment of metal centers, they exhibit high activity and selectivity in photocatalytic reactions. At the same time, due to the synergistic effect between dual atoms, catalysts with a dual-atom structure have better performance than those with a single-atom structure.

[0004] Based on this, the present invention designs a Ti–Ni dual-atom dispersed copolymer that is expected to be a material with excellent photocatalytic performance for the removal of EOPs. Summary of the Invention

[0005] Aiming at the above problems existing in the prior art, the purpose of the present invention is to provide a preparation method and an application of a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties. A Ti–Ni dual-atom dispersed copolymer material with directional electron delocalization properties of the present invention not only has low energy consumption, low cost, and small pollution during the preparation process; on the basis of not destroying the copolymer substrate structure, Ti–Ni dual atoms are successfully loaded to endow it with directional electron delocalization properties. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties of the present invention is optimized to have high-efficiency photocatalytic EOPs degradation performance and has wide applications in pollutant removal and environmental remediation.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, the copolymer is a thin-layer network composed of carbon and nitrogen, and Ti and Ni atoms are loaded on the copolymer, and the loading of Ti and Ni atoms results in the formation of directional electron delocalization on the copolymer.

[0008] Furthermore, the thin-layer network is stacked by two-dimensional carbon nitride structures, and the Ti and Ni atoms are loaded on the copolymer in the form of single atoms, and the interatomic distance is 0.2 - 1.0 Å; the directional electron delocalization on the copolymer is specifically the electron transfer from the nitrogen-carbon structure to the Ti atom and from the Ti atom to the Ni atom.

[0009] A preparation method of a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties, comprising the following steps:

[0010] S1 Preparation of copolymer substrate: Under normal temperature and pressure, monomer one with an aldehyde group and monomer two with an amino group and a triazine ring structure are fully stirred in an organic mixed solvent, and then transferred to the inner liner of a reaction kettle and placed in an oven for solvothermal reaction to condense the two monomers into a carbon nitride copolymer. After the reaction is completed, it is cooled to room temperature, and the copolymer material is centrifuged and separated, and then the copolymer material is thoroughly washed to remove unreacted raw materials;

[0011] S2 First metal loading: The copolymer material obtained in step S1 is added to a C1-C3 lower alcohol solvent, ultrasonically stirred, and a titanium source solution is slowly added dropwise to the mixed solution, and then transferred to a rotary evaporator to evaporate the solvent to obtain a copolymer material loaded with Ti;

[0012] S3 Second metal loading: The copolymer material loaded with Ti in step S2 is re-added to a C1-C3 lower alcohol solvent, and acetylacetone is added. A nickel source solution is slowly added dropwise to the mixed solution, and then transferred to a rotary evaporator to evaporate the solvent to obtain a copolymer material loaded with Ti-Ni;

[0013] S4 Calcination activation: The copolymer material loaded with Ti-Ni in step S3 is placed in a tubular furnace and calcined under an argon atmosphere to obtain a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0014] Furthermore, in step S1, monomer one with an aldehyde group is terephthalaldehyde, monomer two with an amino group and a triazine ring structure is 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, and the molar ratio of monomer one to monomer two is 1:0.5 - 2, preferably 1:1.

[0015] Further, in step S1, the organic mixed solvent is N,N-dimethylformamide, dimethyl sulfoxide and acetic acid with a volume ratio of 4-6:0.5-2:1, and the volume ratio of N,N-dimethylformamide, dimethyl sulfoxide and acetic acid is preferably 5:1:1; the molar concentrations of monomer one and monomer two in the organic mixed solvent are both 0.1-0.2 mol / L, preferably 0.15 mol / L.

[0016] Further, in step S1, the temperature of the solvothermal reaction is 120-180 °C, preferably 150 °C, and the reaction time is 40-55 h, preferably 45-48 h.

[0017] Further, in step S2, the titanium source is titanium tetrachloride, and the concentration of the titanium source solution is 0.8-1.2 mg / mL, preferably 1.0 mg / mL; the mass ratio of the titanium source to the copolymer material in step S2 is 2-8:1, preferably 5-6:1.

[0018] Further, in step S2, the C1-C3 lower alcohol solvent is selected from methanol. The copolymer material obtained in step S1 is added to the methanol solvent, and the ratio of the material to methanol is controlled at 80-120 mg / 70 mL, preferably 100 mg / 70 mL.

[0019] Further, in step S3, the nickel source is nickel chloride, and the concentration of the nickel source solution is 0.8-1.2 mg / mL, preferably 1.0 mg / mL; the mass ratio of the nickel source to the titanium source in step S3 to that in step S2 is 1:0.5-2, preferably 1:1;

[0020] In step S3, the mass ratio of the nickel source to acetylacetone is 1:30-50, preferably 1:40.

[0021] Further, in step S4, the calcination temperature is 200-300 °C, preferably 250 °C, and the calcination time is 1.5-2.5 h, preferably 2 h.

[0022] Application of the described Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties in the photocatalytic degradation of organic pollutants.

[0023] To optimize the photocatalytic performance of carbon nitride copolymers, the present invention adopts a brand-new method to construct a copolymer with dual-atom dispersion of Ti–Ni: using 2,4,6-tris(4-aminophenyl)-1,3,5-triazine with photoreactivity and terephthalaldehyde as organic monomers, through their dispersion and hydrothermal treatment in a mixed organic solvent, the aldehyde group and amino group are polymerized at high temperature to form a two-dimensional carbon nitride copolymer with a hexagonal network structure. At the same time, metal ion sources are dispersed on the two-dimensional carbon nitride copolymer during high-temperature rotary evaporation to prevent their agglomeration and increase the stability of their loading. Finally, unreacted organic ligands are removed by high-temperature calcination to obtain a Ti–Ni dual-atom dispersed copolymer with electron-directed delocalization.

[0024] In terms of monomer selection, the triazine structure in the center of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine ensures that the material has photocatalytic response. The three branched chains extending outwards are conducive to the construction of a two-dimensional network. The linear terephthalaldehyde, as an organic ligand, undergoes polycondensation with the three linear chains of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine to construct a two-dimensional carbon nitride polymer network, ensuring the stability of its structure. The formed carbon nitride polymer network has a hexagonal network structure, which is conducive to the deposition of metal ions in the cavity. Chelating titanium metal with acetylacetone prevents the deposition of Ni metal from destroying the deposition of Ti in the carbon nitride polymer structure. Finally, impurity organic substances are removed by high-temperature calcination and the material is activated.

[0025] Compared with the prior art, the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties in the present invention has the following advantages in actual use:

[0026] 1. The present invention provides a green synthesis method for a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties. As an optimized Ti–Ni dual-atom dispersed copolymer, it has the property of directional electron delocalization, and this material can achieve efficient EOPs degradation performance. Compared with traditional photocatalysts, the Ti–Ni dual-atom dispersed copolymer of the present invention has a wider visible light response range, a lower recombination rate of photogenerated electrons and holes, and exhibits obvious electron delocalization properties. The direction of electron delocalization is from the nitrogen-carbon copolymer substrate to the Ti atom and from the Ti atom to the Ni atom.

[0027] 2. Compared with other single-atom loaded photocatalysts, the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties has dual-atom active sites and can synergistically photocatalytically degrade EOPs.

[0028] 3. Compared with other metal-atom dispersed photocatalysts, the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties has a higher metal loading amount, reaching 4.52 wt%, and has more active sites for photocatalytic reactions.

[0029] 4. Since the Ti-Ni diatomic dispersed copolymer with directional electron delocalization of the present invention is easy to prepare, has high photocatalytic efficiency and selectivity, it has great application potential in the fields of water pollution control. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a high-resolution transmission electron microscopy image of the Ti-Ni diatomic dispersion copolymer with directional electron delocalization prepared in Example 1;

[0031] Figure 2 This is a high-resolution transmission electron microscopy image of the Ti-Ni diatomic dispersion copolymer with directional electron delocalization prepared in Example 3;

[0032] Figure 3 This is a high-resolution transmission electron microscopy image of the Ti-Ni diatomic dispersed copolymer with directional electron delocalization properties prepared in Example 6. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] In the following examples, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine, terephthalaldehyde, N,N-dimethylformamide, dimethyl sulfoxide, titanium tetrachloride and titanium chloride were purchased from Beijing Bailingwei Technology Co., Ltd. without further purification.

[0035] Of course, those skilled in the art should know that the selection of the raw materials is only a preferred method of the present invention, and the various parameters can be adjusted according to actual needs. 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and terephthalaldehyde can be replaced by other organic monomers having amino and aldehyde groups. Therefore, the replacement of raw materials can also achieve the effects of the present invention to a certain extent, and should also fall within the scope of protection of the present invention. Specific embodiments are as follows:

[0036] Example 1

[0037] In this embodiment, the specific steps of the preparation method of the Ti-Ni diatomic dispersed copolymer with directional electron delocalization properties are as follows:

[0038] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) into a 100 mL mixture of N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1 and stir at room temperature for 4.0 h to mix thoroughly.

[0039] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner, and then place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0040] (3) After the solution is cooled to room temperature, centrifuge to separate the material from the solvent. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash 3 times with water and methanol respectively, and dry in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0041] (4) Add the dried material (100 mg) to 70 mL of methanol solvent, and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixed solution, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0042] (5) Re-add the above-evaporated material to 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixed solution, and transfer it to a rotary evaporator to evaporate the solvent to dryness to obtain a dried material.

[0043] (6) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0044] The high-resolution transmission electron microscopy image of the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties prepared in Example 1 is as Figure 1 shown.

[0045] Example 2

[0046] In this example, the specific steps for the preparation method and application of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0047] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to a 100 mL mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide and acetic acid with a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0048] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner, and then place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0049] (3) After the solution is cooled to room temperature, the material and the solvent are separated by centrifugation. The material is placed in 50 mL of N,N-dimethylformamide and stirred for 24.0 h, then centrifuged. It is washed three times with water and methanol respectively, and then placed in a vacuum drying oven for drying for 12.0 h to obtain a carbonitrogen polymer substrate.

[0050] (4) The dried material (100 mg) is added to 70 mL of methanol solvent and ultrasonically stirred for 2.0 h. Subsequently, 5.0 mL of titanium tetrachloride solution (0.8 mg / mL) is added dropwise to the mixture, and the solvent is evaporated to dryness in a rotary evaporator.

[0051] (5) The above-mentioned dried material is re-added to 70 mL of methanol solvent, and 200 μL of acetylacetone solution is added. It is ultrasonically stirred for 2.0 h. Subsequently, 5.0 mL of nickel chloride solution (0.8 mg / mL) is added dropwise to the mixture, and the solvent is evaporated to dryness in a rotary evaporator to obtain a dried material.

[0052] (6) The above-mentioned material is placed in a tubular furnace and calcined in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0053] Example 3

[0054] In this example, the specific steps for the preparation method and application of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0055] (1) 2,4,6-Tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) are added to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide and acetic acid with a volume ratio of 5:1:1, and stirred at room temperature for 4.0 h to be fully mixed.

[0056] (2) The mixed solution is transferred to a 200 mL stainless steel autoclave with a polytetrafluoroethylene lining and then placed in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0057] (3) After the solution is cooled to room temperature, the material and the solvent are separated by centrifugation. The material is placed in a 50 mL solution of N,N-dimethylformamide and stirred for 24.0 h, then centrifuged. It is washed three times with water and methanol respectively, and then placed in a vacuum drying oven for drying for 12.0 h to obtain a carbonitrogen polymer substrate.

[0058] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of titanium tetrachloride solution (1.2 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0059] (5) Re-add the above-evaporated material to 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of nickel chloride solution (1.2 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness to obtain the dried material.

[0060] (6) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0061] The high-resolution transmission electron microscopy image of the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties prepared in Example 3 is as Figure 2 shown.

[0062] Example 4

[0063] In this example, the specific steps for the preparation method and application of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0064] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid with a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0065] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner and place it in an oven at 120 °C for hydrothermal reaction for 48.0 hours.

[0066] (3) After the solution is cooled to room temperature, separate the material from the solvent by centrifugation. Put the material into a 50 mL solution of N,N-dimethylformamide, stir for 24.0 h, then centrifuge and wash it 3 times with water and methanol respectively, and place it in a vacuum drying oven to dry for 12.0 h to obtain a carbonitrogen polymer substrate.

[0067] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0068] (5) Redissolve the above-evaporated material in 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and ultrasonically stir for 2.0 h. Subsequently, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to obtain a dry material.

[0069] (6) Place the above material in a tube furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0070] Example 5

[0071] In this example, the specific steps for the preparation method and application of a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0072] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to a 100 mL mixture containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0073] (2) Transfer the mixture to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner and place it in an oven at 180 °C for hydrothermal reaction for 48.0 hours.

[0074] (3) After the solution cools to room temperature, separate the material from the solvent by centrifugation. Place the material in a 50 mL solution of N,N-dimethylformamide, stir for 24.0 h, then centrifuge and wash it 3 times with water and methanol respectively, and dry it in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0075] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and ultrasonically stir for 2.0 h. Subsequently, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent.

[0076] (5) Redissolve the above-evaporated material in 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and ultrasonically stir for 2.0 h. Subsequently, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to obtain a dry material.

[0077] (6) Place the above material in a tube furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0078] Example 6

[0079] In this example, the specific steps for the preparation method and application of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0080] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0081] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0082] (3) After the solution is cooled to room temperature, separate the material from the solvent by centrifugation. Put the material into a 50 mL solution of N,N-dimethylformamide, stir for 24.0 h, then centrifuge and wash it 3 times with water and methanol respectively, and dry it in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0083] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Then, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixed solution and transfer it to a rotary evaporator to evaporate the solvent.

[0084] (5) Re-add the evaporated material to 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and stir ultrasonically for 2.0 h. Then, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixed solution and transfer it to a rotary evaporator to evaporate the solvent to obtain a dried material.

[0085] (6) Place the above material in a tube furnace and calcine it in an argon atmosphere at 200 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0086] The high-resolution transmission electron microscope image of the Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties prepared in Example 6 is as Figure 3 shown.

[0087] Figures 1 - 3 The loading form of metal single atoms can be observed, and the bright spots of single-atom loading are circled in the figure. In addition, according to the spherical aberration electron microscope image, it can be observed that the interatomic distance on the copolymer prepared in the embodiment of the present invention is 0.2-1.0 Å.

[0088] Comparative Example 1

[0089] In this example, the specific steps for the preparation method of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0090] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and glyoxal (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to fully mix.

[0091] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0092] (3) After the solution cools to room temperature, centrifuge to separate the material from the solvent. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash 3 times with water and methanol respectively, and dry in a vacuum drying oven for 12.0 h to obtain a carbon nitride polymer substrate.

[0093] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Then, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixed solution and transfer it to a rotary evaporator to evaporate the solvent.

[0094] (5) Re-add the above-evaporated material to 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and stir ultrasonically for 2.0 h. Then, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixed solution and transfer it to a rotary evaporator to evaporate the solvent to obtain a dried material.

[0095] (6) Place the above material in a tube furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0096] Comparative Example 2

[0097] In this example, the specific steps for the preparation method of the Ti single-atom dispersed copolymer are as follows:

[0098] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0099] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a PTFE liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 h.

[0100] (3) After the solution is cooled to room temperature, centrifuge to separate the material from the solvent. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash 3 times with water and methanol respectively, and dry in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0101] (4) Add the dried material (100 mg) to 70 mL of methanol solvent, and stir ultrasonically for 2.0 h. Then, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixed solution, and transfer it to a rotary evaporator to evaporate the solvent.

[0102] (5) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a copolymer with single-atom dispersed Ti.

[0103] Comparative Example 3

[0104] In this example, the specific steps of the preparation method of the Ni single-atom dispersed copolymer are as follows:

[0105] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0106] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a PTFE liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 h.

[0107] (3) After the solution is cooled to room temperature, centrifuge to separate the material from the solvent. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash 3 times with water and methanol respectively, and dry in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0108] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of nickel chloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0109] (5) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a copolymer with single-atom dispersed Ni.

[0110] Comparative Example 4

[0111] In this example, the specific steps of the preparation method of the Ti-Fe dual-atom dispersed copolymer are as follows:

[0112] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid with a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0113] (2) Transfer the mixed solution to a 200 mL stainless steel autoclave with a polytetrafluoroethylene liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0114] (3) After the solution is cooled to room temperature, separate the material from the solvent by centrifugation. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash it 3 times with water and methanol respectively, and place it in a vacuum drying oven to dry for 12.0 h to obtain a carbonitrogen polymer substrate.

[0115] (4) Add the dried material (100 mg) to 70 mL of methanol solvent and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0116] (5) Re-add the above dried material to 70 mL of methanol solvent, add 200 μL of acetylacetone solution, and stir ultrasonically for 2.0 h. Subsequently, dropwise add 5.0 mL of iron chloride solution (1.0 mg / mL) to the mixture, and transfer it to a rotary evaporator to evaporate the solvent to dryness to obtain a dried material.

[0117] (6) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Fe dual-atom dispersed copolymer.

[0118] Comparative Example 5

[0119] In this example, the specific steps of the preparation method of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0120] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0121] (2) Transfer the mixed solution to a 200 mL stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0122] (3) After the solution is cooled to room temperature, centrifuge to separate the material from the solvent. Put the material into 50 mL of N,N-dimethylformamide, stir for 24.0 h, then centrifuge, wash 3 times with water and methanol respectively, and dry in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0123] (4) Add the dried material (100 mg) to 70 mL of methanol solvent, and stir ultrasonically for 2.0 h. Then, simultaneously add 5.0 mL of titanium tetrachloride solution (1.0 mg / mL), 5.0 mL of nickel chloride solution (1.0 mg / mL), and 200 μL of acetylacetone solution to the mixed solution, and transfer it to a rotary evaporator to evaporate the solvent to dryness.

[0124] (5) Place the above material in a tubular furnace and calcine it in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0125] Comparative Example 6

[0126] In this example, the specific steps of the preparation method of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties are as follows:

[0127] (1) Add 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (15 mmol) and terephthalaldehyde (15 mmol) to 100 mL of a mixed solution containing N,N-dimethylformamide, dimethyl sulfoxide, and acetic acid in a volume ratio of 5:1:1, and stir at room temperature for 4.0 h to mix well.

[0128] (2) Transfer the mixed solution to a 200 mL stainless steel reactor with a polytetrafluoroethylene liner and place it in an oven at 150 °C for hydrothermal reaction for 48.0 hours.

[0129] (3) After the solution is cooled to room temperature, the material and the solvent are separated by centrifugation. The material is placed in 50 mL of N,N-dimethylformamide and stirred for 24.0 h, then centrifuged, washed three times with water and methanol respectively, and dried in a vacuum drying oven for 12.0 h to obtain a carbonitrogen polymer substrate.

[0130] (4) The dried material (100 mg) is added to 70 mL of methanol solvent and ultrasonically stirred for 2.0 h. Subsequently, 5.0 mL of titanium tetrachloride solution (1.0 mg / mL) is added dropwise to the mixture, and the solvent is evaporated to dryness in a rotary evaporator.

[0131] (5) The above-mentioned dried material is re-added to 70 mL of methanol solvent and ultrasonically stirred for 2.0 h. Subsequently, 5.0 mL of nickel chloride solution (1.0 mg / mL) is added dropwise to the mixture, and the solvent is evaporated to dryness in a rotary evaporator to obtain a dried material.

[0132] (6) The above-mentioned material is placed in a tube furnace and calcined in an argon atmosphere at 250 °C for 2.0 h to obtain a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties.

[0133] Application Example 1

[0134] The Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties obtained in Examples 1-6 is used to carry out the bisphenol A (BPA) degradation experiment under xenon lamp irradiation.

[0135] The experimental conditions are as follows: 200 mL of BPA aqueous solution with a concentration of 0.01 mmol / L is measured and placed in a photoreactor, 10 mg of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties is added, and magnetic stirring is carried out in the dark for 30 min to reach the adsorption-desorption equilibrium. Then, a 300W xenon lamp equipped with an AM 1.5G filter is turned on, and the light intensity is set to 100 ± 2 mW / cm -2 The photocatalytic degradation reaction is carried out, and samples are taken regularly, and the BPA concentration in the reactor is detected by high-performance liquid chromatography and high-performance gas chromatography.

[0136] Application Example 2

[0137] The Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties obtained in Examples 1-6 is used to carry out the carbamazepine (CBZ) degradation experiment under xenon lamp irradiation.

[0138] The experimental conditions were as follows: 200 mL of a 0.01 mmol / L aqueous solution of CBZ was measured and placed in a photoreactor. 10 mg of a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties was added. The mixture was magnetically stirred in the dark for 30 min to reach the adsorption-desorption equilibrium. Then, a 300 W xenon lamp equipped with an AM 1.5G filter was turned on, and the light intensity was set to 100 ± 2 mW / cm -2 The photocatalytic degradation reaction was carried out, and samples were taken at regular intervals. The concentration of CBZ in the reactor was detected by high-performance liquid chromatography and high-performance gas chromatography.

[0139] Application Example 3

[0140] The degradation experiment of ibuprofen (IBP) was carried out using the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties obtained in Examples 1-6 under xenon lamp irradiation.

[0141] The experimental conditions were as follows: 200 mL of a 0.01 mmol / L aqueous solution of IBP was measured and placed in a photoreactor. 10 mg of a Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties was added. The mixture was magnetically stirred in the dark for 30 min to reach the adsorption-desorption equilibrium. Then, a 300 W xenon lamp equipped with an AM 1.5G filter was turned on, and the light intensity was set to 100 ± 2 mW / cm -2 The photocatalytic degradation reaction was carried out, and samples were taken at regular intervals. The concentration of IBP in the reactor was detected by high-performance liquid chromatography and high-performance gas chromatography.

[0142] Application Example 4

[0143] The degradation experiment of bisphenol A (BPA) was carried out using the materials obtained in Comparative Examples 1-6 under xenon lamp irradiation.

[0144] The experimental conditions were as follows: 200 mL of a 0.01 mmol / L aqueous solution of BPA was measured and placed in a photoreactor. 10 mg of the material prepared in the comparative example was added. The mixture was magnetically stirred in the dark for 30 min to reach the adsorption-desorption equilibrium. Then, a 300 W xenon lamp equipped with an AM1.5G filter was turned on, and the light intensity was set to 100 ± 2 mW / cm -2 The photocatalytic degradation reaction was carried out, and samples were taken at regular intervals. The concentration of BPA in the reactor was detected by high-performance liquid chromatography and high-performance gas chromatography.

[0145] The single-atom loading amounts of the Ti–Ni dual-atom dispersed copolymers with directional electron delocalization properties prepared in different examples are shown in Table 1.

[0146]

[0147] Ti-Ni dual-atom dispersed copolymers with directional electron delocalization properties prepared by different embodiments all exhibit ultra-high photocatalytic degradation performance for different pollutants, and the reaction results are shown in Table 2.

[0148] Comparing Comparative Example 1, Example 2, and Example 3, it can be found that simultaneously reducing and increasing the concentration of the metal source has a slight impact on photocatalytic EOPs. A metal source concentration of 1 mg / mL is preferably used, which has the highest photocatalytic pollutant degradation performance. Comparing Comparative Example 1, Example 4, and Example 5, it can be found that fine-tuning the dissolution heat reaction temperature has a certain impact on the photocatalytic performance of the material. A reaction temperature of 150 °C is preferably used to synthesize a material with the best performance, but the photocatalytic degradation performance of EOPs still remains above 90%. Comparing Comparative Example 1 and Example 6, it can be found that reducing the calcination temperature has an obvious impact on the performance of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties, which may be due to the reduction in temperature affecting the stability of metal anchoring in the material and the removal of reaction impurity organic matter.

[0149]

[0150] The results of the photocatalytic degradation performance of BPA by materials synthesized in different comparative examples are shown in Table 3.

[0151] Comparing Comparative Example 1 with Comparative Example 1, it can be found that when terephthalaldehyde in the raw materials is replaced with glyoxal, the material completely loses its photocatalytic performance, which may be related to the failure of the carbon-nitrogen copolymer backbone to be successfully assembled. Comparing Comparative Example 1 with Comparative Examples 2 and 3, it can be found that when only Ti metal or Ni metal is added, the photocatalytic degradation rates of the material for BPA are only 18.6% and 15.7%, respectively, indicating that heteronuclear metal dual atoms play an important role in the photocatalytic process. Comparing Comparative Example 1 and Comparative Example 4, it can be found that when Ni metal is replaced with Fe metal, its photocatalytic performance will be greatly reduced, proving that Ni metal plays an important role in the photocatalytic process of dual atoms. Comparing Comparative Example 1 and Comparative Example 5, it can be found that the photocatalytic degradation rate of BPA by the material synthesized by simultaneously adding Ti metal and Ni metal during the synthesis process is reduced to 67.4%, indicating that the simultaneous addition of the two metals cannot effectively exert the synergistic effect of dual atoms. Comparing Comparative Example 1 and Comparative Example 6, it can be found that not adding acetylacetone as a chelating agent for Ti metal during the synthesis process will lead to a significant reduction in photocatalytic performance.

[0152]

[0153] The above-described embodiments are only a preferred solution of the present invention, but they are not intended to limit the present invention. For example, although in the above embodiments, the protective gas used in the high-temperature calcination experiment is argon, it does not mean that only argon can achieve the effects of the present invention. Using an inert gas, such as nitrogen, to protect the material from being damaged during the high-temperature calcination process can achieve the effects of the present invention.

[0154] The content described in this specification is only an enumeration of the implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments.

Claims

1. A Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties, characterized in that, The copolymer is a thin-layer network composed of carbon and nitrogen. Ti and Ni atoms are loaded on the copolymer, and the loading of Ti and Ni atoms enables the formation of directional delocalization of electrons on the copolymer. The preparation method of the Ti-Ni dual-atom dispersed copolymer with directional electron delocalization properties includes the following steps: S1 Preparation of copolymer substrate: At normal temperature and pressure, monomer one with an aldehyde group and monomer two with an amino group and a triazine ring structure are fully stirred in an organic mixed solvent, and then transferred to the inner lining of a reaction kettle and placed in an oven for solvothermal reaction to condense the two monomers into a carbon-nitrogen copolymer. After the reaction is completed, it is cooled to room temperature, and the copolymer material is separated by centrifugation, and then the copolymer material is washed thoroughly to remove unreacted raw materials. S2 First metal loading: The copolymer material obtained in step S1 is added to a C1-C3 lower alcohol solvent, ultrasonically stirred, and a titanium source solution is slowly added dropwise to the mixed solution, and then transferred to a rotary evaporator to evaporate the solvent to dryness to obtain a copolymer material loaded with Ti. S3 Second metal loading: The copolymer material loaded with Ti in step S2 is re-added to a C1-C3 lower alcohol solvent, and acetylacetone is added. A nickel source solution is slowly added dropwise to the mixed solution, and then transferred to a rotary evaporator to evaporate the solvent to dryness to obtain a copolymer material loaded with Ti-Ni. S4 Calcination activation: The copolymer material loaded with Ti-Ni in step S3 is placed in a tubular furnace and calcined under an argon atmosphere to obtain a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties. In step S1, monomer one with an aldehyde group is terephthalaldehyde, and monomer two with an amino group and a triazine ring structure is 2,4,6−tris(4−aminophenyl)−1,3,5−triazine, and the molar ratio of monomer one to monomer two is 1:0.5~2. In step S1, the temperature of the solvothermal reaction is 120-180 °C, and the reaction time is 40-55 h. In step S2, the mass ratio of the titanium source to the copolymer material is 2~8:

1. In step S3, the mass ratio of the nickel source to the titanium source in step S2 is 1:0.5~2, and the mass ratio of the nickel source to acetylacetone in step S3 is 1:30~50.

2. The Ti–Ni dual-atom dispersed copolymer with directional electron delocalization property as described in claim 1, wherein The thin-layer network is stacked by two-dimensional carbon-nitrogen structures. The Ti and Ni atoms are loaded on the copolymer in the form of single atoms, and the interatomic distance is 0.2-1.0 Å. The directional delocalization of electrons on the copolymer is specifically the electron transfer from the nitrogen-carbon structure to the Ti atom and from the Ti atom to the Ni atom.

3. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as claimed in claim 1, characterized in that, In step S1, the molar ratio of monomer one to monomer two is 1:

1.

4. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 1, characterized in that, In step S1, the organic mixed solvent is N,N−dimethylformamide, dimethyl sulfoxide and acetic acid with a volume ratio of 4~6:0.5~2:1, and the molar concentrations of monomer one and monomer two in the organic mixed solvent are both 0.1~0.2 mol / L.

5. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties according to claim 4, characterized in that, In step S1, the volume ratio of N,N−dimethylformamide, dimethyl sulfoxide and acetic acid is 5:1:1; the molar concentrations of monomer one and monomer two in the organic mixed solvent are both 0.15 mol / L.

6. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties according to claim 1, characterized in that, In step S1, the temperature of the solvothermal reaction is 150 °C, and the reaction time is 45 - 48 h.

7. The preparation method of a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties according to claim 1, characterized in that, In step S2, the titanium source is titanium tetrachloride, and the concentration of the titanium source solution is 0.8 - 1.2 mg / mL; the mass ratio of the titanium source to the copolymer material in step S2 is 5 - 6:

1.

8. The preparation method of a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 7, characterized in that, In step S2, the concentration of the titanium source solution is 1.0 mg / mL.

9. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as claimed in claim 1, wherein, In step S3, the nickel source is nickel chloride, and the concentration of the nickel source solution is 0.8 - 1.2 mg / mL; the mass ratio of the nickel source to the titanium source in step S2 in step S3 is 1:1; In step S3, the mass ratio of the nickel source to acetylacetone is 1:

40.

10. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 9, characterized in that, In step S3, the concentration of the nickel source solution is 1.0 mg / mL.

11. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 1, characterized in that, In step S4, the calcination temperature is 200 - 300 °C, and the calcination time is 1.5 - 2.5 h.

12. A Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 11, characterized in that, In step S4, the calcination temperature is 250 °C, and the calcination time is 2 h.

13. Use of a Ti–Ni dual-atom dispersed copolymer with directional electron delocalization properties as described in claim 1 in the photocatalytic degradation of organic pollutants.

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