Method for preparing S, O-Co / UiO-66 and derivative catalyst thereof by atom anchoring method and application

Abstract

The invention belongs to the technical field of novel material design and preparation and environmental protection, and discloses a method for preparing S, O-Co / UiO-66 and a derivative catalyst thereof through an atom anchoring method and application. A monatomic anchoring method is adopted, specifically, a specific coordination synthesis environment is formed on a stable Zr-MOF framework, Co ions are guided to be accurately anchored to a needed MOFs intrinsic structure and a defect site of a terminal ligand in a monatomic form, and finally atomic-scale dispersed Co active sites are formed; the S, O-Co / UiO-66 derivative catalyst with Zr-O-S-Co active sites with higher activity, more excellent charge transfer and higher NO molecule oxygen activation capability is further prepared. The denitration activity test conditions of the catalyst are as follows: the NO: 700 ppm, the CO: 1400 ppm and the N2 are used as balance gases, and the gas flow rate is 200 mL / min.

Description

Technical Field

[0001] This invention belongs to the fields of novel material design and preparation and environmental protection technology, and relates to a method and application of atomically anchored controlled preparation of S,O-Co / UiO-66 catalyst and its derivatives. Background Technology

[0002] As research on MOF materials catalyzing CO-SCR reactions continues to advance, the problems of monometallic MOF materials are becoming increasingly apparent. These include low catalytic denitrification efficiency at low temperatures, a limited number of active sites for catalysis, and poor structural stability at high temperatures. Therefore, more researchers are exploring the application of bimetallic MOF materials in SCR catalysis. Compared to monometallic MOF materials, bimetallic MOF materials exhibit better catalytic performance. The introduced second metal ion can act as an electron mediator, providing a new pathway for electron transfer from ligands to the metal cluster, and the bimetallic structure can also achieve better synergistic effects.

[0003] Furthermore, MOF material derivatives maintain high specific surface area and porosity, preserving their structural diversity. The organic structure undergoes transformation through pyrolysis, which helps improve the denitrification stability of MOF catalysts. Previous studies have demonstrated that Co-doped Zr-based MOF derivative catalysts can maintain a CO conversion rate of no less than 45% at 275℃, but Zr remains after high-temperature pyrolysis. 4+ d 0 Deep-seated problems include electronic configuration and nonreducibility, limited charge transfer between ligands and metal nodes, and orbital symmetry that is unfavorable to O2 activation.

[0004] Therefore, in response to the aforementioned problems with Co-Zr bimetallic MOF precursors, this invention, based on extensive experiments, unexpectedly discovered that a Co-Zr bimetallic MOF precursor with superior charge transfer and higher NO molecular oxygen activation ability can be regulated through a special synergistic single-atom anchoring method. Using this precursor as a calcination template, more efficient low-temperature active and stable S,O-Co / UiO-66 and its derivative catalysts containing a unique Zr-OS-Co structure were prepared. Summary of the Invention

[0005] Studies have found that inorganic metal salts such as Co and Zr used in conventional synthesis methods play a crucial role in ligand formation. 4+ d 0The electronic configuration and irreducibility, the limited charge transfer between ligands and metal nodes, and the orbital symmetry unfavorable to O2 activation lead to problems such as easy framework collapse and low activity in Co-Zr-UiO-66. Therefore, this invention employs a special synergistic single-atom anchoring method in the preparation of S,O-Co / UiO-66 materials: unlike the common synthesis of heterometallic nodes or heterojunctions, this method uses special experimental techniques to create a specific coordination synthesis environment on a highly stable Zr-MOF framework, guiding Co ions to precisely anchor in single-atom form to the desired intrinsic structure of MOFs and the defect sites of terminal ligands, ultimately forming atomically dispersed Co active sites.

[0006] This invention includes: 1. In the preparation of MOFs synthesis solutions, targeting zirconium chloride and cobalt chloride commonly used in traditional hydrothermal methods, this study, based on extensive raw material screening and synthetic characterization experiments, unexpectedly screened tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanoic acid) and (2,3-butanedione dioxime)cobalt(III) long-chain organic molecular salts as metal salts. It was then discovered that by adding a specific amount of 2,5-thiophene dicarboxylic acid stimulant, coordination reactions between Zr and Co metal nanoparticles and specific organic ligands could be achieved. Without the stimulant, MOF materials are difficult to synthesize, with low yields and difficulty in precipitation. After adding the stimulant, a hollow spherical structure S,O-Co / UiO-66 precursor with a diameter of 45.87 nm was successfully synthesized. 2. Using S,O-Co / UiO-66 precursor as a calcination template, a highly active atomically bridged Zr-OS-Co structure was formed via pyrolysis, significantly improving electron transfer efficiency. This resulted in the preparation of a Zr-OS-Co structure with more efficient active sites and superior charge transfer properties. Figure 4 Computational analysis of the obtained structure revealed that the addition of Co promotes charge transfer to Zr, resulting in an increase in Zr charge from +0.422|e| to +0.686|e| compared to before the formation of the Zr-OS-Co structure. This also resulted in a higher NO molecular oxygen activation capacity (reaching 98% activity at 200℃) for the S,O-Co / UiO-66 derivative catalyst. To date, the above method has not been reported for the preparation of S,O-Co / UiO-66 derivatives.

[0007] Technical solution of the present invention:

[0008] A method for preparing S,O-Co / UiO-66 and its derivative catalysts by atomic anchoring includes the following steps:

[0009] (1) Preparation of UiO-66:

[0010] A mixed system of N,N-dimethylformamide-ethanol-ultrapure water was prepared. Tetra(2,2,6,6-tetramethyl-3,5-heptanediic acid)zirconium was dissolved in the mixed system and stirred until a homogeneous solution was formed. The stimulant 2,5-thiophene dicarboxylic acid and 12 mol / L concentrated hydrochloric acid were added, and the mixture was sonicated until completely homogeneous. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 120°C for 48 hours, ensuring that the relative humidity was ≤5% for the first 24 hours and continuously venting for the next 24 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, yielding a yellow crystalline precipitate. This precipitate was washed several times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder for later use.

[0011] The volume ratio of N,N-dimethylformamide, ethanol, and ultrapure water is 6:1:1.

[0012] The mass ratio of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediic acid) to 2,5-thiophene dicarboxylic acid is 1:1.2;

[0013] The volume ratio of concentrated hydrochloric acid to N,N-dimethylformamide is 1:8;

[0014] (2) Preparation of defective UiO-66:

[0015] The activated UiO-66 powder was dispersed in a solution of concentrated hydrochloric acid and methanol in a volume ratio of 1:19 and stirred in a 40°C water bath for 6 hours. The material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral, thus obtaining defective UiO-66, which was temporarily stored in methanol for later use to avoid drying.

[0016] (3) Preparation of S,O-Co / UiO-66 precursor:

[0017] Long-chain molecular salt (2,3-butanedione dioxime) cobalt(III) was dissolved in methanol as a cobalt source stimulant and stirred until the solution was homogeneous to obtain a mixed solution. Under an inert atmosphere (such as argon), wet defective UiO-66 was added to the mixed solution and magnetically stirred at room temperature until completely homogeneous. The mixture was then allowed to stand in the dark for 48 hours to ensure the presence of Co. 2+ Ions can diffuse slowly and precisely into the interior of the MOF, forming atomically dispersed active centers. The product was washed with a large amount of methanol by centrifugation until the supernatant was colorless to completely remove any physically adsorbed cobalt species. Finally, the resulting purple solid was vacuum dried at 60°C for 12 hours to obtain the catalyst S,O-Co / UiO-66.

[0018] The molar ratio of (2,3-butanedione dioxime)cobalt(III) to tetra(2,2,6,6-tetramethyl-3,5-heptanediol)zirconium is 0.5:1 to 1.5:1.

[0019] The methanol is anhydrous methanol.

[0020] (4) The catalyst S,O-Co / UiO-66 was calcined at 800℃ under N2 atmosphere for 4h to prepare a bimetallic S,O-Co / UiO-66 derivative with high stability.

[0021] The bimetallic S,O-Co / UiO-66 derivative with a highly stable structure was applied to the CO-SCR denitrification reaction. The catalytic performance was tested under the conditions of NO: 700ppm, CO: 1400ppm, N2 as the equilibrium gas, and a gas flow rate of 200mL / min. The denitrification activity reached more than 98% at 125-300℃.

[0022] The beneficial effects of this invention: This invention proposes a method for preparing bimetallic Co-Zr-UiO-66 derivatives using a synergistic single-atom anchoring method. The obtained samples have uniform particle size and complete morphology. CO-SCR test results show that the catalyst is effective at 125-300 °C. o A denitrification efficiency of 98% was achieved within the C temperature range. This method can form unique Zr-OS-Co active sites, exhibiting more controllable charge transfer and superior molecular oxygen activation ability, representing a novel and efficient method for preparing MOF catalysts. This invention provides a valuable reference for expanding the field of novel low-temperature catalyst preparation. Attached Figure Description

[0023] Figure 1 These are CO-SCR selective catalytic activity test diagrams of the S,O-Co / UiO-66 derivative materials prepared in Examples 1, 2, 3, and 4 of this invention.

[0024] Figure 2 These are X-ray crystal diffraction patterns of the S,O-Co / UiO-66 derivatives prepared in Examples 1, 2 and 3 of this invention.

[0025] Figure 3 These are scanning electron microscope images of the bimetallic MOFs derivatives prepared in this invention, wherein (a) is prepared in Example 1, (b) is prepared in Example 2, and (c) is prepared in Example 3.

[0026] Figure 4 This is a charge density difference diagram of ONNO adsorbed on (a) Zr-N / C and (b) ZrCo-N / C according to the present invention. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0028] Example 1

[0029] The preparation method of S,O-Co / UiO-66 (Co:Zr = 1:2) derivatives specifically includes the following steps:

[0030] (1) Preparation of UiO-66:

[0031] 824.29 mg of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediol) and 206.59 mg of 2,5-thiophene dicarboxylic acid were dissolved in 80 mL of DMF, and 10 mL of concentrated hydrochloric acid was added as a modifier. After sonication, the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted in an oven at 120°C for 48 hours. After the reaction, the solution was allowed to cool naturally to room temperature, resulting in a yellow crystalline precipitate. This precipitate was washed three times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder. The activated UiO-66 was dispersed in a solution of concentrated hydrochloric acid and methanol at a volume ratio of 1:19 and gently stirred in a water bath at 40°C for 6 hours. The treated material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral. The resulting defective UiO-66 was temporarily stored in fresh methanol for later use, avoiding drying.

[0032] (2) Preparation of S,O-Co / UiO-66 (Co:Zr = 1:2) precursor:

[0033] The core single-atom cobalt anchoring stage utilizes (2,3-butanedione dioxime)cobalt(III) as an advanced cobalt source stimulant. First, 180.54 mg of (2,3-butanedione dioxime)cobalt(III) was dissolved in 70 mL of methanol to prepare a very low-concentration cobalt source solution. Subsequently, under an inert atmosphere (such as argon), wet defect-type UiO-66 material was added to this solution. The entire system was allowed to react at room temperature in the dark for 48 hours to ensure Co... 2+ Ions can diffuse slowly and precisely into the interior of the MOF, forming atomically dispersed active centers. After the reaction is complete, the product is washed with a large amount of methanol by centrifugation until the supernatant is colorless to completely remove any physically adsorbed cobalt species. Finally, the resulting purple solid is vacuum dried at 60°C for 12 hours to obtain the target catalyst S,O-Co / UiO-66 (Co:Zr= 1:2).

[0034] S,O-Co / UiO-66 (Co:Zr = 1:2) was calcined in a tube furnace at 800℃ under N2 atmosphere for 4 h to prepare a black bimetallic S,O-Co / UiO-66 (Co:Zr = 1:2) derivative powder sample with high stability.

[0035] The selective catalytic activity of CO-SCR is shown in [reference]. Figure 1 ;

[0036] XRD characterization is shown in [reference needed]. Figure 2 ;

[0037] SEM results are shown below. Figure 3 (a);

[0038] Example 2

[0039] The preparation method of S,O-Co / UiO-66 (Co:Zr = 1:1) derivatives specifically includes the following steps:

[0040] (1) Preparation of UiO-66:

[0041] 824.29 mg of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediol) and 206.59 mg of 2,5-thiophene dicarboxylic acid were dissolved in 80 mL of DMF, and 10 mL of concentrated hydrochloric acid was added as a modifier. After sonication, the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted in an oven at 120°C for 48 hours. After the reaction, the solution was allowed to cool naturally to room temperature, resulting in a yellow crystalline precipitate. This precipitate was washed three times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder. The activated UiO-66 was dispersed in a solution of concentrated hydrochloric acid and methanol at a volume ratio of 1:19 and gently stirred in a water bath at 40°C for 6 hours. The treated material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral. The resulting defective UiO-66 was temporarily stored in fresh methanol for later use, avoiding drying.

[0042] (2) Preparation of S,O-Co / UiO-66 (Co:Zr = 1:1) precursor:

[0043] The core single-atom cobalt anchoring stage utilizes (2,3-butanedione dioxime)cobalt(III) as an advanced cobalt source stimulant. First, 361.07 mg of (2,3-butanedione dioxime)cobalt(III) was dissolved in 70 mL of methanol to prepare a very low-concentration cobalt source solution. Subsequently, under an inert atmosphere (such as argon), wet defect-type UiO-66 material was added to this solution. The entire system was allowed to react at room temperature in the dark for 48 hours to ensure Co... 2+Ions can diffuse slowly and precisely into the interior of the MOF, forming atomically dispersed active centers. After the reaction is complete, the product is washed with a large amount of methanol by centrifugation until the supernatant is colorless to completely remove any physically adsorbed cobalt species. Finally, the resulting purple solid is vacuum dried at 60°C for 12 hours to obtain the target catalyst S,O-Co / UiO-66 (Co:Zr= 1:1).

[0044] S,O-Co / UiO-66 (Co:Zr = 1:1) was calcined in a tube furnace at 800℃ under N2 atmosphere for 4 hours to prepare a black bimetallic S,O-Co / UiO-66 (Co:Zr = 1:1) derivative powder sample with high stability.

[0045] The selective catalytic activity of CO-SCR is shown in [reference]. Figure 1 ;

[0046] XRD characterization is shown in [reference needed]. Figure 2 ;

[0047] SEM results are shown below. Figure 3 (b);

[0048] Example 3

[0049] The preparation method of S,O-Co / UiO-66 (Co:Zr = 3:2) derivatives specifically includes the following steps:

[0050] (1) Preparation of UiO-66:

[0051] 824.29 mg of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediol) and 206.59 mg of 2,5-thiophene dicarboxylic acid were dissolved in 80 mL of DMF, and 10 mL of concentrated hydrochloric acid was added as a modifier. After sonication, the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted in an oven at 120°C for 48 hours. After the reaction, the solution was allowed to cool naturally to room temperature, resulting in a yellow crystalline precipitate. This precipitate was washed three times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder. The activated UiO-66 was dispersed in a solution of concentrated hydrochloric acid and methanol at a volume ratio of 1:19 and gently stirred in a water bath at 40°C for 6 hours. The treated material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral. The resulting defective UiO-66 was temporarily stored in fresh methanol for later use, avoiding drying.

[0052] (2) Preparation of S,O-Co / UiO-66 (Co:Zr = 3:2) precursor:

[0053] The core single-atom cobalt anchoring stage utilizes (2,3-butanedione dioxime)cobalt(III) as an advanced cobalt source stimulant. First, 541.61 mg of (2,3-butanedione dioxime)cobalt(III) was dissolved in 70 mL of methanol to prepare a very low-concentration cobalt source solution. Subsequently, under an inert atmosphere (such as argon), wet defect-type UiO-66 material was added to this solution. The entire system was allowed to react at room temperature in the dark for 48 hours to ensure the Co²⁻¹ concentration was maintained. + Ions can diffuse slowly and precisely into the interior of the MOF, forming atomically dispersed active centers. After the reaction is complete, the product is washed with a large amount of methanol by centrifugation until the supernatant is colorless to completely remove any physically adsorbed cobalt species. Finally, the resulting purple solid is vacuum dried at 60°C for 12 hours to obtain the target catalyst S,O-Co / UiO-66 (Co:Zr = 3:2).

[0054] S,O-Co / UiO-66 (Co:Zr = 3:2) was calcined in a tube furnace at 800℃ under N2 atmosphere for 4 hours to prepare a black bimetallic S,O-Co / UiO-66 (Co:Zr = 3:2) derivative powder sample with high stability.

[0055] The selective catalytic activity of CO-SCR is shown in [reference]. Figure 1 ;

[0056] XRD characterization is shown in [reference needed]. Figure 2 ;

[0057] SEM results are shown below. Figure 3 (c);

[0058] Example 4

[0059] The preparation method of UiO-66 derivatives specifically includes the following steps:

[0060] 824.29 mg of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediol) and 206.59 mg of 2,5-thiophene dicarboxylic acid were dissolved in 80 mL of DMF, and 10 mL of concentrated hydrochloric acid was added as a modifier. After sonication and dissolution, the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene and reacted in an oven at 120°C for 48 hours. After the reaction was completed, the solution was allowed to cool naturally to room temperature to obtain a yellow crystalline precipitate. The precipitate was washed three times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder for later use.

[0061] The selective catalytic activity of CO-SCR is shown in [reference]. Figure 1 ;

[0062] Example 5

[0063] The preparation method of Co / UiO-66 (Co:Zr = 1:1) derivatives specifically includes the following steps:

[0064] (1) Preparation of UiO-66:

[0065] 824.29 mg of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediol) was dissolved in 80 mL of DMF, and 10 mL of concentrated hydrochloric acid was added as a modifier. After ultrasonic dissolution, the solution was transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted in an oven at 120°C for 48 hours. After the reaction, the solution was allowed to cool naturally to room temperature, resulting in a yellow crystalline precipitate. This precipitate was washed three times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder. The activated UiO-66 was dispersed in a solution of concentrated hydrochloric acid and methanol at a volume ratio of 1:19 and gently stirred in a water bath at 40°C for 6 hours. The treated material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral. The resulting defective UiO-66 was temporarily stored in fresh methanol for later use, avoiding drying.

[0066] (2) Preparation of Co / UiO-66 (Co:Zr = 1:1) precursor:

[0067] The core single-atom cobalt anchoring stage utilizes (2,3-butanedione dioxime)cobalt(III) as an advanced cobalt source stimulant. First, 361.07 mg of (2,3-butanedione dioxime)cobalt(III) was dissolved in 70 mL of methanol to prepare a very low-concentration cobalt source solution. Subsequently, under an inert atmosphere (such as argon), wet defect-type UiO-66 material was added to this solution. The entire system was allowed to react at room temperature in the dark for 48 hours to ensure Co... 2+ Ions can diffuse slowly and precisely into the interior of the MOF, forming atomically dispersed active centers. After the reaction is complete, the product is washed with a large amount of methanol by centrifugation until the supernatant is colorless to completely remove any physically adsorbed cobalt species. Finally, the resulting purple solid is vacuum dried at 60°C for 12 hours to obtain the target catalyst Co / UiO-66 (Co:Zr = 1:1).

[0068] Co / UiO-66 (Co:Zr = 1:1) was calcined in a tube furnace at 800℃ under N2 atmosphere for 4 hours to prepare a black bimetallic Co / UiO-66 (Co:Zr = 1:1) derivative powder sample with high stability.

[0069] The selective catalytic activity of CO-SCR is shown in [reference]. Figure 1 ;

[0070] The denitrification activity of the catalysts prepared in Examples 1-5 was characterized from 125°C to 300°C, and the results are as follows: Figure 1 :

[0071] Depend on Figure 1 It is evident that the activities of the three catalysts prepared in this embodiment, S,O-Co / UiO-66 and UiO-66, are positively correlated with temperature. Furthermore, the S,O-Co / UiO-66 catalyst achieves a NO conversion rate exceeding 95% within the 125-300℃ range, exhibiting a wide reaction temperature window. This material lowers the CO-SCR reaction temperature. Among them, S,O-Co / UiO-66 (Co:Zr = 1:1) exhibits the highest activity, with a maximum NO conversion rate approaching 98.5%. The denitrification activity of the catalyst without the addition of 2,5-thiophene dicarboxylic acid is 64.3%, which is lower than that of the catalyst with the addition of 2,5-thiophene dicarboxylic acid. These results indicate that the formed special Zr-OS-Co structure significantly improves electron transfer efficiency, and the Zr and Co atoms produce a synergistic effect, enhancing the catalytic activity of the material.

[0072] XRD analysis was performed on the crystal structures of the catalysts prepared in Examples 1-3, and the results are as follows: Figure 2 :

[0073] The figure clearly shows sharp diffraction peaks at approximately 28.1° and 31.4°, consistent with the reported crystal planes. 2θ = 31.4° corresponds to the Co3O4 and ZrO2 crystal planes. These results indicate that the prepared S,O-Co / UiO-66 bimetallic material forms Co and Zr oxide species upon calcination. The Co3O4 and ZrO2 species possess excellent redox properties, sufficient surface oxygen vacancies (SOVs), and high oxygen storage / release capacity. Their presence significantly enhances the redox performance of the material, thereby improving the CO-SCR catalytic activity.

[0074] SEM analysis was performed on the catalysts prepared in Examples 1-3, and the results are as follows: Figure 3 :

[0075] Depend on Figure 3 As can be seen, the S,O-Co / UiO-66 bimetallic derivative consists of many interconnected particles of different sizes and shapes, exhibiting a cluster structure with a size range of 5-6 micrometers. Compared with the structure of conventionally synthesized cobalt-zirconium bimetallic MOF materials, this structure exhibits a higher specific surface area, which is conducive to the formation of more active sites, providing more surface oxygen vacancies for catalytic reactions and accelerating the adsorption and conversion of reactants.

Claims

1. A method for preparing S,O-Co / UiO-66 and its derivative catalysts by atomic anchoring, characterized in that, The steps are as follows: (1) Preparation of UiO-66: A mixed system of N,N-dimethylformamide-ethanol-ultrapure water was prepared. Tetra(2,2,6,6-tetramethyl-3,5-heptanediic acid)zirconium was dissolved in the mixed system and stirred until a homogeneous solution was formed. The stimulant 2,5-thiophene dicarboxylic acid and 12 mol / L concentrated hydrochloric acid were added, and the mixture was sonicated until completely homogeneous. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene (PTFE) and reacted at 120°C for 48 hours, ensuring that the relative humidity was ≤5% for the first 24 hours and continuously venting for the next 24 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, yielding a yellow crystalline precipitate. This precipitate was washed several times by centrifugation with DMF and methanol, and finally activated under vacuum at 100°C for 12 hours to obtain activated UiO-66 powder for later use. (2) Preparation of defective UiO-66: The activated UiO-66 powder was dispersed in a solution of concentrated hydrochloric acid and methanol in a volume ratio of 1:19 and stirred in a 40°C water bath for 6 hours. The material was then repeatedly washed by centrifugation with methanol until the supernatant was neutral, thus obtaining defective UiO-66, which was temporarily stored in methanol for later use to avoid drying. (3) Preparation of S,O-Co / UiO-66 precursor: Long-chain molecular salt (2,3-butanedione dioxime) cobalt(III) was dissolved in methanol as a cobalt source stimulant and stirred until the solution was homogeneous to obtain a mixed solution. Under an inert atmosphere (such as argon), wet defective UiO-66 was added to the mixed solution and magnetically stirred at room temperature until completely homogeneous. The mixture was then allowed to stand in the dark for 48 hours to ensure the presence of Co. 2+ Ions can diffuse slowly and precisely into the interior of MOF to form atomically dispersed active centers; the product is washed with methanol by centrifugation until the supernatant is colorless to completely remove any physically adsorbed cobalt species; finally, the obtained purple solid is vacuum dried at 60°C for 12 hours to obtain the catalyst S,O-Co / UiO-66. (4) The catalyst S,O-Co / UiO-66 was calcined at 800℃ under N2 atmosphere for 4h to prepare S,O-Co / UiO-66 and its derivative catalysts.

2. The method according to claim 1, characterized in that, In step (1), The volume ratio of N,N-dimethylformamide, ethanol, and ultrapure water is 6:1:

1. The mass ratio of tetrazirconium tetrakis(2,2,6,6-tetramethyl-3,5-heptanediic acid) to 2,5-thiophene dicarboxylic acid is 1:1.2; The volume ratio of concentrated hydrochloric acid to N,N-dimethylformamide is 1:

8.

3. The method according to claim 1, characterized in that, In step (3), The molar ratio of (2,3-butanedione dioxime)cobalt(III) to tetra(2,2,6,6-tetramethyl-3,5-heptanediol)zirconium is 0.5:1 to 1.5:1; The methanol is anhydrous methanol.

4. The S,O-Co / UiO-66 and its derivative catalysts obtained by the method according to any one of claims 1-3 are applied to CO-SCR denitrification reaction.

5. The application according to claim 4, characterized in that, CO-SCR denitrification reaction conditions: Catalytic performance was tested under the conditions of NO: 700ppm, CO: 1400ppm, N2 as the equilibrium gas, and a gas flow rate of 200mL / min. The denitrification activity reached over 98% at 125-300℃.

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