Room-temperature water-phase rapid synthesis method and application of metal-doped ZIF-8 material

Abstract

The invention relates to the technical field of metal organic framework material catalysts, and discloses a room-temperature water-phase rapid synthesis method and application of a metal-doped ZIF-8 material.The method comprises the steps that deionized water serves as a green solvent, the metal-doped ZIF-8 material is rapidly synthesized under the room-temperature condition, the pH of a system is regulated to be in the optimal coordination interval through triethylamine, and the metal-doped ZIF-8 material is obtained. The method has the advantages that the reaction time is greatly shortened, the metal utilization rate is obviously increased, the product yield is efficiently optimized, the synthesis process is green and environment-friendly, the energy consumption is low, large-scale production can be realized, meanwhile, the synthesis strategy can be expanded to preparation of metal doped ZIF materials such as Fe, Co, Cu, Sn, Pt, Ru and Rh, and the method has a wide application prospect; the metal-doped ZIF-8 material and the derived monatomic catalyst prepared by the invention show excellent performance in the fields of CO2 reduction, catalytic degradation and the like.

Description

Technical Field

[0001] This invention relates to the field of metal-organic framework catalyst technology, and in particular to a rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials and its application. Background Technology

[0002] Zeoliticimidazolateframework-8 (ZIF-8) and its metal-substituted derivatives have attracted much attention in various fields such as catalysis, gas separation, and environmental remediation due to their structural tunability, high specific surface area, and good chemical stability. Among them, Ni-ZIF-8, as an important variant of ZIF-8, has shown excellent performance potential in photocatalytic degradation and CO2 reduction.

[0003] However, existing methods for synthesizing Ni-ZIF-8 have many significant drawbacks: 1. Low reaction efficiency: The traditional hydrothermal method requires 24 hours to complete the synthesis of Ni-ZIF-8. Even if some improved methods shorten the time, they still require high temperature and high pressure conditions, which leads to a significant increase in energy consumption. 2. Low Ni utilization: In the synthetic systems reported in the existing literature, the utilization rate of Ni element is low, and a large amount of Ni metal precursors do not participate in the coordination reaction, resulting in a waste of resources; 3. Poor environmental compatibility: Methanol and other organic solvents are often used as reaction media. The evaporation of these solvents poses environmental risks, and the cost of solvent recovery is high, which is not in line with the trend of green chemical development. 4. Limited product yield: Due to problems such as insufficient ligand dissolution and unbalanced nucleation rate, the product yield of conventional systems is usually less than 60%, which is difficult to meet the needs of large-scale applications.

[0004] Therefore, developing a metal-doped ZIF-8 synthesis method that is fast, has high metal utilization, is environmentally friendly, and has excellent yield is of great practical significance and application value. In the existing technology, although some studies have attempted to synthesize ZIF-like materials at room temperature, the controllable doping of transition metals and noble metals into ZIF-8, the simultaneous optimization of high metal ion utilization and high yield have not yet been achieved, and there is a lack of a green synthesis system that can be applied on a large scale. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials, comprising the following steps: Step (1) Dissolve the doped metal precursor and the zinc source precursor in deionized water to obtain a mixed solution of metal salts; Step (2) Dissolve 2-methylimidazole in deionized water to obtain a ligand solution; Step (3) Add triethylamine to the ligand solution, stir, then add the metal salt mixture solution, react, and obtain the reaction suspension; Step (4) Centrifuge the reaction suspension, wash the centrifuged precipitate and dry it to obtain metal-doped ZIF-8 material.

[0006] Preferably, in step (1), the zinc source precursor includes Zn(NO3)2·6H2O, ZnSO4·7H2O, and ZnCl2; the doped metal precursor includes transition metal salts, noble metal salts, and main group metal salts. The transition metal salts include metal salts containing Ni, Fe, Co, and Cu. The noble metal salts include metal salts containing Pt, Ru, and Rh. The main group metal salts include metal salts containing Sn.

[0007] Preferably, in step (1), the amount of zinc source precursor accounts for 80-99% of the total molar amount of metal raw materials, and the amount of doped metal precursor accounts for 1-20% of the total molar amount of metal raw materials.

[0008] Preferably, in step (1), the total molar concentration of the metal in the metal salt mixed solution is 0.01-0.1 mol / L. This concentration range can ensure the uniformity of the reaction system and avoid the agglomeration of metal ions caused by excessive concentration.

[0009] Preferably, in step (2), the ratio of the molar number of 2-methylimidazole to the total molar number of metal raw materials is (4-12):1, preferably 8:1. Sufficient ligands can ensure complete coordination of metal ions and improve product purity.

[0010] Preferably, in step (3), the molar ratio of triethylamine to 2-methylimidazole in the reaction suspension is (0.5-1.5):1, preferably 1:1. This range is the optimal condition for the coordination of metal ions with 2-methylimidazole, which can ensure that the coordination reaction proceeds fully and improve the metal utilization rate.

[0011] Preferably, in step (3), the reaction conditions are: reacting at 20-25°C for 2-5 hours.

[0012] Preferably, in step (4), the washing method of the centrifuged precipitate is: washing with deionized water and anhydrous ethanol alternately; the drying conditions of the centrifuged precipitate are: drying temperature of 60-80℃ and drying time of 8-12h.

[0013] In the above process, deionized water is used as a green solvent, avoiding the pollution problems of organic solvents; triethylamine, as an organic base regulator, plays a key role in regulating the rapid nucleation and growth of ZIF-8 through deprotonation, thereby promoting Ni 2+ Zn2+ Uniform dispersion of metal ions guides directional crystal growth and improves reaction repeatability and product dispersion. Combined with enhanced mass transfer through strong stirring at room temperature, the coordination and nucleation rate of metal ions and ligands is significantly increased, allowing the reaction to be completed within 2-5 hours, thus significantly shortening the preparation time. Furthermore, this synthesis strategy has good versatility; the nickel source precursor can be replaced with transition metal salts such as Fe, Co, and Cu, or main group metal salts such as Sn, as well as noble metal salts such as Pt, Ru, and Rh, all of which can achieve efficient synthesis of the corresponding metal-doped ZIF-8 materials. It also demonstrates significant advantages in improving the utilization rate of noble metal raw materials and suppressing metal agglomeration.

[0014] The metal-doped ZIF-8 material was prepared using the room-temperature aqueous phase rapid synthesis method described above.

[0015] Furthermore, the metal-doped ZIF-8 material, after calcination, forms a metal single-atom catalyst. The metal single atoms are uniformly dispersed in the carbon-nitrogen support in a coordinated form, without obvious metal agglomeration. In the catalytic reaction, the active sites can be fully exposed. The metal single-atom catalyst is used for CO2 reduction reaction, catalytic degradation of pollutants, and other applications.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials. The synthesis method of this invention has the following advantages: (1) High reaction efficiency: Triethylamine accelerates ligand deprotonation and enhances mass transfer, shortening the reaction time to 2-5h, which is significantly higher than the 24h of the traditional hydrothermal method. (2) Significantly improved metal utilization: The optimal pH environment regulated by triethylamine promotes full coordination of metal ions. Under the same amount of metal feed, the Ni utilization (i.e. doping amount) is increased by an order of magnitude compared with the system without triethylamine, thus improving the utilization of raw materials. (3) Green and environmentally friendly with low energy consumption: Deionized water is used as a solvent to avoid organic solvent pollution. The room temperature reaction does not require high temperature and high pressure, which significantly reduces energy consumption compared with the hydrothermal method and meets the needs of green chemical development. (4) Excellent product yield: The product yield can reach more than 88.43%, which is more than 6 times higher than the 14.03% of the existing literature methods, meeting the needs of large-scale production; (5) Strong universality: The synthesis strategy of the present invention is not only applicable to nickel-doped ZIF-8 materials, so that the prepared Ni-ZIF-8 materials have good crystal structure, high specific surface area and porosity, and the nickel is uniformly dispersed; in addition, the synthesis strategy of the present invention can also be extended to the preparation of ZIF-8 materials doped with transition metals such as Fe, Co, Cu, Sn and noble metals such as Pt, Ru, Rh, etc., providing a universal solution for the green synthesis of various functional materials.

[0017] 2. The metal-doped ZIF-8 material of the present invention can form a metal single-atom catalyst after calcination. The single-atom catalyst can be used for CO2 reduction reaction and catalytic degradation of pollutants. The single-atom catalyst exhibits excellent CO selectivity in CO2 reduction reaction and its comprehensive performance is better than that of traditional catalysts. When catalytically degrading pollutants in water, it can efficiently activate oxidants and achieve rapid removal of pollutants. Attached Figure Description

[0018] Figure 1 TEA-Ni prepared in Example 1 of the present invention 0.04 -ZIF-8 SEM image; Figure 2 TEA-Ni prepared in Example 1 of the present invention 0.04 -ZIF-8 EDS plot; Figure 3 TEA-Ni prepared in Example 1 of the present invention 0.04 XRD pattern of ZIF-8; Figure 4 TEA-Ni prepared in Example 1 of the present invention 0.04 -A physical image of ZIF-8; Figure 5 TEA-Pt prepared for Example 4 of the present invention 0.01 Pt prepared by ZIF-8 and Comparative Example 2 0.01 XRD pattern of ZIF-8; Figure 6 TEA-Pt prepared for Example 4 of the present invention 0.01 - Pt0.01-ZIF-8 prepared in Comparative Example 2 and physical images of ZIF-8. Figure 7 TEA-Fe prepared in Example 5 of the present invention 0.04 -A physical image of ZIF-8; Figure 8 TEA-Fe prepared in Example 5 of the present invention 0.04 XRD pattern of ZIF-8; Figure 9 TEA-Ni prepared in Example 1 of this invention0.04 -ZIF-8 and Ni prepared in Comparative Example 1 0.04 TEA-Ni was obtained by calcining ZIF-8 at 900℃ for 4 hours in an argon atmosphere. 0.04 -NC single-atom catalyst (left) and Ni 0.04 - Aberration-corrected transmission electron micrograph of an NC single-atom catalyst (right); Figure 10 TEA-Ni prepared in Example 1 of this invention 0.04 -ZIF-8 and Ni prepared in Comparative Example 1 0.04 TEA-Ni was obtained by calcining ZIF-8 at 900℃ for 4 hours in an argon atmosphere. 0.04 -NC single-atom catalyst and Ni 0.04 XRD pattern of NC single-atom catalyst; Figure 11 TEA-Pt prepared for Example 4 of the present invention 0.01 TEA-Pt was obtained by calcining ZIF-8 at 900℃ for 4 hours in an argon atmosphere. 0.01 -NC single-atom catalyst and Pt prepared in Comparative Example 2 0.01 Pt obtained by calcining ZIF-8 at 900℃ for 4 hours in an argon atmosphere 0.01 XRD pattern of NC single-atom catalyst; Figure 12 TEA-Ni prepared in Example 1 of this invention 0.04 -ZIF-8 and Ni prepared in Comparative Example 1 0.04 TEA-Ni was obtained by calcining ZIF-8 at 900℃ for 4 hours in an argon atmosphere. 0.04 -NC single-atom catalyst and Ni 0.04 Comparison of electrocatalytic CO2 reduction performance of -NC single-atom catalysts. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1 This embodiment discloses a TEA-Ni 0.04 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.08 mmol Ni(NO3)2·6H2O and 1.92 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 30 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add 2.2 mL of triethylamine dropwise to the ligand solution and stir for 10 min to obtain a well-mixed and clear solution. Then slowly inject the metal salt mixture solution and stir the reaction at 25 °C for 3 h to obtain a reaction suspension. Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the centrifuged precipitate three times alternately with deionized water and anhydrous ethanol, and then dry it in a vacuum drying oven at 70℃ for 10 h to obtain TEA-Ni0. 04 -ZIF-8.

[0021] Example 2 This embodiment discloses a TEA-Ni 0.02 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.04 mmol Ni(NO3)2·6H2O and 1.96 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 30 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add 2.2 mL of triethylamine dropwise to the ligand solution and stir for 10 min to obtain a well-mixed and clear solution. Then slowly inject the metal salt mixture solution and stir the reaction at 22 °C for 2.5 h to obtain a reaction suspension. Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then dry it in a vacuum drying oven at 70℃ for 10 h to obtain TEA-Ni. 0.02 -ZIF-8.

[0022] Example 3 This embodiment discloses a TEA-Ni 0.1 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.2 mmol Ni(NO3)2·6H2O and 1.8 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 30 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add 2.2 mL of triethylamine dropwise to the ligand solution and stir for 10 min to obtain a well-mixed and clear solution. Then slowly inject the metal salt mixture solution and stir the reaction at 22 °C for 2.5 h to obtain a reaction suspension. Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then dry it in a vacuum drying oven at 70℃ for 10 h to obtain TEA-Ni. 0.1 -ZIF-8.

[0023] Example 4 This embodiment discloses a TEA-Pt 0.01 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.02 mmol chloroplatinic acid and 1.98 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 40 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add 2.2 mL of triethylamine dropwise to the ligand solution and stir for 10 min to obtain a well-mixed clear solution. Then slowly inject the metal salt mixture solution and stir the reaction at 25 °C for 4 h to obtain a pale yellow reaction suspension. Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the centrifuged precipitate three times alternately with deionized water and anhydrous ethanol. Then dry it in a vacuum drying oven at 70℃ for 10 h to obtain TEA-Pt0. 01 -ZIF-8.

[0024] Example 5 This embodiment discloses a TEA-Fe 0.04 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.08 mmol Fe(NO3)3·9H2O and 1.92 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 30 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add 2.2 mL of triethylamine dropwise to the ligand solution and stir for 10 min to obtain a well-mixed and clear solution. Then slowly inject the metal salt mixture solution and stir the reaction at 25 °C for 3 h to obtain a reaction suspension. Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then dry it in a vacuum drying oven at 70℃ for 10 h to obtain TEA-Fe. 0.04 -ZIF-8.

[0025] Comparative Example 1 This comparative example discloses a triethylamine-free Ni 0.04 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.08 mmol Ni(NO3)2·6H2O and 1.92 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of anhydrous methanol, stir for 30 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of anhydrous methanol, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add the metal salt mixed solution to the ligand solution and stir the reaction at 25°C for 24 hours to obtain the reaction suspension; Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the centrifuged precipitate three times alternately with deionized water and anhydrous ethanol. Then dry it in a vacuum drying oven at 70℃ for 10 h to obtain triethylamine-free NiO. 04 -ZIF-8.

[0026] Comparative Example 2 This comparative example discloses a triethylamine-free Pt 0.01 The preparation method of ZIF-8 includes the following steps: Step (1) Weigh 0.02 mmol chloroplatinic acid and 1.98 mmol Zn(NO3)2·6H2O, dissolve them in 30 mL of deionized water, stir for 40 min until completely dissolved, and obtain a mixed solution of metal salts; Step (2) Weigh 16 mmol of 2-methylimidazole, dissolve it in 30 mL of deionized water, stir for 20 min until completely dissolved, and obtain the ligand solution; Step (3) Add the metal salt mixed solution to the ligand solution and stir the reaction at 25°C for 4 hours to obtain a reaction suspension; Step (4) Centrifuge the reaction suspension at 10,000 rpm for 3 min. Wash the centrifuged precipitate three times alternately with deionized water and anhydrous ethanol. Then dry it in a vacuum drying oven at 70℃ for 10 h to obtain triethylamine-free Pt0. 01 -ZIF-8.

[0027] Experimental Example I. Yield and Metal Utilization Test 1. Product yield test: The yields of the products prepared in Examples 1-4 and Comparative Examples 1-2 were tested, and the results are shown in Table 1 (Note: The product yields in Table 1 are calculated based on the theoretical yield obtained from the addition of Zn, and the yields are calculated by comparing the theoretical yields with the experimentally obtained mass). Table 1 As shown in Table 1, the product yields of Examples 1, 2, 4, and 5 were all above 88%. A comparison between Comparative Example 1 and Example 1 shows that the addition of triethylamine during the synthesis process significantly affected the product yield. This is because triethylamine regulates the rapid nucleation and growth of ZIF-8 through deprotonation and guides the directional growth of crystals through weak coordination, improving reaction reproducibility and product dispersion, thereby increasing the product yield. A comparison between Comparative Example 2 and Example 4 shows that… Figure 5-6 The room temperature aqueous phase system and triethylamine regulation strategy of this invention are compatible with the dissolution and coordination reactions of noble metal precursors such as Pt, Ru, and Rh (e.g., chloroplatinic acid, ruthenium trichloride, and rhodium trichloride), forming a homogeneous reaction system without the need for additional organic solvents such as methanol and DMF. In summary, the room-temperature aqueous phase rapid synthesis method of metal-doped ZIF-8 material of the present invention has the advantages of high reaction efficiency, green and environmentally friendly, low energy consumption, excellent product yield, and strong versatility.

[0028] 2. Metal utilization rate test: EDS energy dispersive spectroscopy analysis was performed on the products prepared in Examples 1-3 and Comparative Example 1 to detect the Ni and Zn contents in each product. The results are shown in Table 2. Table 2 As shown in Table 1, the metal doping amount in Examples 1-3 is positively correlated with the feed ratio, indicating that the method of the present invention can conveniently control the metal doping amount in ZIF-8. Compared with Comparative Example 1, the nickel doping amount in Example 1 is much greater than that in Comparative Example 1, indicating that the method of the present invention can improve the utilization rate of the doped metal salt and the metal doping amount in ZIF-8. In summary, the room temperature aqueous phase rapid synthesis method of metal-doped ZIF-8 material of the present invention can significantly improve the metal utilization rate.

[0029] II. Structural Characterization 1. The TEA-Ni prepared in Example 1 0.04 -ZIF-8 (Actual product image as shown) Figure 4 Structural characterization, such as Figure 1-3 As shown, the particles exhibit nano- to micron-sized particle sizes, with uniform distribution of Ni, Zn, and N elements, as characterized by SEM and EDS mapping. XRD patterns show that they have a typical ZIF-8 crystal structure. 2. Regarding the TEA-Pt prepared in Example 4 0.01 -ZIF-8, TEA-Fe prepared in Example 5 0.04 Pt prepared by ZIF-8 and Comparative Example 2 0.01 XRD testing was performed using ZIF-8, and the results are as follows: Figure 5-8 As shown; TEA-Pt prepared in Example 4 0.01 -ZIF-8, TEA-Fe prepared in Example 5 0.04 -ZIF-8 has a typical ZIF-8 crystal structure, with Pt and Fe doped metal elements uniformly dispersed.

[0030] III. Detection of Metal-Doped ZIF-8 Derived Ni-NC Single-Atom Catalysts 1. Aberration-corrected transmission electron microscopy examination: The TEA-Ni prepared in Example 1 of this invention 0.04 -ZIF-8 and Ni prepared in Comparative Example 1 0.04 -ZIF-8 was calcined at 900℃ for 4 hours in an argon atmosphere. The resulting single-atom catalyst was then analyzed. Figure 9 As shown, the left figure shows the TEA-Ni prepared in Example 1. 0.04 TEA-Ni obtained after calcination of ZIF-8 0.04 -Aberration-corrected transmission electron micrograph of the NC single-atom catalyst, the right image showing Ni prepared in Comparative Example 1. 0.04 Ni obtained after calcination of ZIF-8 0.04 - Aberration-corrected transmission electron micrograph of an NC single-atom catalyst.

[0031] 2. XRD test Take the TEA-Ni prepared in Example 1 of this invention 0.04 -ZIF-8, TEA-Pt prepared in Example 4 0.01 Ni prepared by -ZIF-8 and Comparative Example 1 0.04 Pt prepared by -ZIF-8 and Comparative Example 2 0.01 -ZIF-8 was calcined at 900℃ for 4 hours in an argon atmosphere to obtain TEA-Ni. 0.04-NC single-atom catalyst, TEA-Pt 0.01 -NC single-atom catalyst, Ni 0.04 -NC single-atom catalyst and Pt 0.01 XRD analysis of the NC single-atom catalyst yielded the following results: Figure 10-11 As shown.

[0032] 3. Catalytic performance test: The TEA-Ni prepared in Example 1 of this invention 0.04 -ZIF-8 and Ni prepared in Comparative Example 1 0.04 -ZIF-8 was calcined at 900℃ for 4 hours in an argon atmosphere to obtain TEA-Ni. 0.04 -NC single-atom catalyst and Ni 0.04 -NC single-atom catalysts are used in electrocatalytic CO2 reduction reactions. The CO Faradaic efficiency and CO current density during the reaction process are calculated by chronoamperometry tests performed at a constant potential. Test results as follows Figure 12 As shown, by Figure 12 It can be seen that the TEA-Ni prepared in Example 1 0.04 TEA-Ni obtained after calcination of ZIF-8 0.04 The -NC single-atom catalyst exhibits superior CO Faradaic efficiency and CO current density, and its overall performance is better than that of the TEA-Ni prepared in Comparative Example 1. 0.04 Ni obtained after calcination of ZIF-8 0.04 -NC single-atom catalyst.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials, characterized in that, Includes the following steps: Step (1) Dissolve the doped metal precursor and the zinc source precursor in deionized water to obtain a mixed solution of metal salts; Step (2) Dissolve 2-methylimidazole in deionized water to obtain a ligand solution; Step (3) Add triethylamine to the ligand solution, stir, then add the metal salt mixture solution, react, and obtain the reaction suspension; Step (4) Centrifuge the reaction suspension, wash the centrifuged precipitate and dry it to obtain metal-doped ZIF-8 material.

2. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (1), the zinc source precursor includes Zn(NO3)2·6H2O, ZnSO4·7H2O and ZnCl2; the doped metal precursor includes transition metal salts, noble metal salts and main group metal salts, the transition metal salts include metal salts containing Ni, Fe, Co and Cu, the noble metal salts include metal salts containing Pt, Ru and Rh, and the main group metal salts include metal salts containing Sn.

3. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (1), the amount of zinc source precursor accounts for 80-99% of the total molar amount of metal raw materials, and the amount of doped metal precursor accounts for 1-20% of the total molar amount of metal raw materials.

4. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (1), the total molar concentration of the metal in the metal salt mixture is 0.01-0.1 mol / L.

5. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (2), the ratio of the number of moles of 2-methylimidazole to the total number of moles of metal raw materials is (4-12):

1.

6. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (3), the molar ratio of triethylamine to 2-methylimidazole in the reaction suspension is (0.5-1.5):

1.

7. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (3), the reaction conditions are: reacting at 20-25℃ for 2-5 hours.

8. The rapid room-temperature aqueous phase synthesis method for metal-doped ZIF-8 materials according to claim 1, characterized in that, In step (4), the washing method of the centrifuged precipitate is: washing with deionized water and anhydrous ethanol alternately; the drying conditions of the centrifuged precipitate are: drying temperature of 60-80℃ and drying time of 8-12h.

9. A metal-doped ZIF-8 material prepared by a room-temperature aqueous phase rapid synthesis method for metal-doped ZIF-8 materials as described in any one of claims 1-8.

10. The metal-doped ZIF-8 material according to claim 9, characterized in that, The metal-doped ZIF-8 material is calcined to form a metal single-atom catalyst, which is used in CO2 reduction reaction and catalytic degradation of pollutants.

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