Preparation method and application of molybdenum single-atom porous carbon

Abstract

The present invention provides a preparation method and application of molybdenum single-atom porous carbon. The preparation method of molybdenum single-atom porous carbon is characterized by comprising the steps of using MgO nanosheets, mixing with a precursor solution containing C, S and Mo, drying to obtain a powder, pyrolyzing it, and subjecting the pyrolysis product to acid treatment to remove the template and nanoparticles. The materials used in this method are cheap and readily available, reducing the overall processing cost and contributing to the popularization and promotion of the technology. The prepared molybdenum single-atom porous carbon can remove ClO at room temperature and pressure. <subgt;4< / subgt;<supgt;‑< / supgt;。本发明还提供了上述方法制得的钼单原子多孔碳和应用。

Description

Technical Field

[0001] The present invention specifically relates to a preparation method and application of molybdenum single-atom porous carbon. Background Art

[0002] Perchlorate (ClO4 - ) is an inorganic oxygen-containing anion. Due to its high water solubility, strong diffusivity, and environmental persistence, it can widely exist in environmental media such as water bodies, soil, and the atmosphere. With the progress of human industrialization, perchlorate is widely used in fields such as the aerospace industry, fireworks manufacturing, national defense, the chemical industry, and the rubber industry, resulting in an increasing accumulation of perchlorate in the environment year by year. As an environmental pollutant, perchlorate poses a risk to human health. It competitively inhibits the absorption of iodide by the thyroid gland, affects the secretion of thyroid hormones, and thus disrupts the normal metabolism and growth and development of the human body. Moreover, perchlorate also endangers the development of the skeletal system and the central nervous system. The "Hygienic Standard for Drinking Water" (GB5749-2022) also includes perchlorate in the extended indicators and implements strict control measures. Therefore, it has become urgent to further research and develop treatment technologies for perchlorate in water.

[0003] Currently, the commonly used removal technologies at home and abroad all have the disadvantages of low removal efficiency or high economic cost. Physical treatment is suitable for small treatment plants, but there are problems such as lack of selectivity and the need for further in-depth treatment. Although biodegradation is very effective, there are still certain limitations in drinking water treatment and groundwater ecological restoration. Therefore, in drinking water and groundwater treatment processes, it is necessary to develop new chemical reduction materials that can remove ClO4 - . Summary of the Invention

[0004] The present invention aims to solve at least one of the above technical problems existing in the prior art. For this reason, the present invention provides a preparation method of molybdenum single-atom porous carbon. The materials used in this method are cheap and easily available, reducing the overall treatment cost, facilitating the popularization and promotion of the technology. The prepared molybdenum single-atom porous carbon can remove ClO4 - .

[0005] The present invention also provides a molybdenum single-atom porous carbon.

[0006] The present invention also provides an application of molybdenum single-atom porous carbon in adsorbing and reducing perchlorate in a biomimetic catalytic system.

[0007] The present invention also provides an application of molybdenum single-atom porous carbon in adsorbing and reducing ClO4 - in water.

[0008] The present invention also provides an application of molybdenum single-atom porous carbon in the detection of trace ClO4 in water. - in water.

[0009] In the first aspect of the present invention, a preparation method of molybdenum single-atom porous carbon is provided, which includes mixing MgO nanosheets with a precursor solution containing C, S, and Mo, drying to obtain a powder and then pyrolyzing, and performing acid treatment on the pyrolysis product to remove the template and nanoparticles.

[0010] Porous carbon materials are carbon materials with various pore sizes. The main preparation methods include direct carbonization method, activation method, and template method. The template method is a method for preparing porous carbon materials with controllable morphology using materials with nano-porous structures, including soft template method and hard template method. Usually, soft templates can use block copolymer surfactants and metal-organic frameworks, etc.

[0011] Hard templates can use zeolites, mesoporous SiO2, MgO, etc. Among them, the MgO template is inexpensive, has high chemical stability and thermal stability, will not react with carbon even at temperatures higher than the carbonization temperature, and is easily removed by washing with dilute acid solution. The carbon nanomaterials prepared by the template method have great application potential in many aspects due to their high specific surface area, thermal stability, and controllable pore structure.

[0012] One technical solution in the preparation method of molybdenum single-atom porous carbon of the present invention has at least the following beneficial effects:

[0013] In the preparation method of molybdenum single-atom porous carbon of the present invention, the materials used are inexpensive and easily available, reducing the overall processing cost and contributing to the popularization and promotion of the technology.

[0014] In the preparation method of molybdenum single-atom porous carbon of the present invention, the mixing of MgO nanosheets and the precursor solution can promote the formation of a porous structure. This porous property is very beneficial for the application of the material, especially in catalysis, adsorption, etc., because it can increase the surface area of the material and enhance the reaction activity.

[0015] In the preparation method of molybdenum single-atom porous carbon of the present invention, through the pyrolysis process, molybdenum atoms are singly dispersed in the porous carbon material. This single-atom dispersion helps to improve the catalytic activity and reduce the interaction between molybdenum atoms, thereby improving the catalytic performance of the material.

[0016] In the preparation method of molybdenum single-atom porous carbon of the present invention, the acid treatment step helps to remove the template and nanoparticles, further improving the purity and stability of the porous carbon material. This helps to ensure that the prepared material meets the expected performance requirements.

[0017] The preparation method of molybdenum single-atom porous carbon of the present invention, and the obtained molybdenum single-atom porous carbon has potential application fields, especially in catalytic reactions. Molybdenum is a commonly used catalyst, and by embedding it atomically into the porous carbon structure, its catalytic efficiency and selectivity can be improved, while reducing the influence of impurities.

[0018] According to some embodiments of the present invention, the preparation method of the MgO nanosheets includes: mixing MgO powder with a dispersant, performing hydrothermal treatment, and sintering the product after filtration and washing.

[0019] According to some embodiments of the present invention, the dispersant includes polyethylene glycol 2000.

[0020] According to some embodiments of the present invention, the temperature of the hydrothermal treatment is 160°C to 200°C.

[0021] According to some embodiments of the present invention, the temperature of the hydrothermal treatment is about 180°C.

[0022] According to some embodiments of the present invention, the time of the hydrothermal treatment is 40h to 60h.

[0023] According to some embodiments of the present invention, the time of the hydrothermal treatment is about 48h.

[0024] According to some embodiments of the present invention, the sintering method includes: heating to 600°C to 700°C at a rate of 10°C / min to 20°C / min and holding for 3h to 10h.

[0025] According to some embodiments of the present invention, the sintering method can be: heating to 650°C at a rate of 15°C / min and holding for 5h.

[0026] According to some embodiments of the present invention, the preparation method of the MgO nanosheets can be:

[0027] Using commercial magnesium oxide powder as the raw material, assisted by the dispersant polyethylene glycol 2000 for hydrothermal reaction, dissolving 1.0 g of MgO powder and 2.1 g of polyethylene glycol 2000 in 200 mL of deionized water, stirring until it becomes a suspension liquid, and then performing hydrothermal treatment at 180°C for 48 h. After filtration, washing, freeze-drying, heating to 650°C in a nitrogen stream (100 sccm) at 15°C / min and holding for 5 h to obtain MgO nanosheets.

[0028] According to some embodiments of the present invention, in the precursor solution, the carbon source includes glucose.

[0029] According to some embodiments of the present invention, in the precursor solution, the sulfur source includes dibenzyl disulfide.

[0030] The role of S in porous carbon includes regulating the electronic structure on the surface of carbon materials.

[0031] According to some embodiments of the present invention, in the precursor solution, the molybdenum source includes sodium molybdate.

[0032] According to some embodiments of the present invention, MgO nanosheets are mixed with a precursor solution containing C, S, and Mo. The method can be as follows:

[0033] 2.5 g of glucose (5 mL of water) + 1.0 g of dibenzyl disulfide (20 mL of ethanol) are first mixed;

[0034] 1 g of the prepared MgO nanosheet template is added;

[0035] 25 mg of sodium molybdate is added, the mixed solution is dried overnight, and ground into a powder.

[0036] According to some embodiments of the present invention, the pyrolysis method includes: under the condition of a protective atmosphere, heating at a rate of 10 °C / min to 20 °C / min to 900 °C to 1000 °C, and holding for 1 h to 3 h.

[0037] During pyrolysis, through heating, the catalyst precursor decomposes, transforms, or rearranges on the MgO template carbon carrier material to form ClO4 with Mo single atoms as the center - Oxygen-depriving reduction active sites.

[0038] According to some embodiments of the present invention, the pyrolysis method can be: under the condition of a protective atmosphere, heating at a rate of 15 °C / min to 950 °C, and holding for 2 h. Then, the reactor is naturally cooled to room temperature under nitrogen protection, and the obtained product is collected.

[0039] The powder can be placed in a corundum boat for pyrolysis.

[0040] The protective atmosphere can be a nitrogen gas flow of 100 sccm.

[0041] According to some embodiments of the present invention, the acid treatment method can be to stir and treat the product with 1.0 mol / L hydrochloric acid for 48 h to remove all templates and nanoparticles.

[0042] According to some embodiments of the present invention, the preparation method further includes washing, filtering, and drying the product after the acid treatment.

[0043] The second aspect of the present invention provides a molybdenum single-atom porous carbon prepared by the described preparation method.

[0044] One technical solution in the technical solution of the molybdenum single-atom porous carbon of the present invention has at least the following beneficial effects:

[0045] For the molybdenum single-atom porous carbon of the present invention, the materials used are cheap and easily available, reducing the overall processing cost and contributing to the popularization and promotion of the technology.

[0046] The molybdenum single-atom porous carbon of the present invention has a wide range of applications, especially in catalysis, adsorption, etc. It has a high specific surface area and high reaction activity.

[0047] According to some embodiments of the present invention, in the molybdenum single-atom porous carbon, the content of Mo ≤ 1.0 wt%.

[0048] The third aspect of the present invention provides the application of the molybdenum single-atom porous carbon of the present invention in adsorbing and reducing perchlorate in a biomimetic catalytic system.

[0049] One technical solution in the application of the molybdenum single-atom porous carbon of the present invention in adsorbing and reducing perchlorate in a biomimetic catalytic system has at least the following beneficial effects:

[0050] The biomimetic catalytic system may be the best candidate to achieve a breakthrough in the technology of catalytic reduction of perchlorate. Although perchlorate is highly inert in the natural environment, microorganisms have evolved a sophisticated enzymatic reaction mechanism for perchlorate reduction under anaerobic conditions. The key active site of perchlorate reductase (PcrAB) is the molybdenum cofactor complex coordinated by pterin (Mo-bisMGD). Specifically, after perchlorate binds to the tetravalent molybdenum (MoⅣ) active site, it is reduced to chlorate (ClO3 - ) through direct oxygen atom transfer (OAT), and at the same time, the tetravalent Mo active site accepts an oxygen atom and is oxidized to a hexavalent molybdenum (MoⅥ) central complex; subsequently, the tetravalent Mo accepts 2e from the respiratory chain - to achieve the transformation from the MoⅥ to the MoⅣ active site. In short, the redox cycle carried out with the transition metal Mo as the active site makes it possible to achieve the reduction and degradation of perchlorate through OAT.

[0051] In the biological method for reducing perchlorate, the key active site of the reductase is the molybdenum cofactor complex coordinated by pterin. The biomimetic catalytic system of the present invention, with the redox cycle carried out with the transition metal Mo as the active site makes it possible to achieve the reduction and degradation of perchlorate through OAT.

[0052] The fourth aspect of the present invention provides a method for reducing ClO4 in water by adsorbing the molybdenum single-atom porous carbon of the present invention. - application.

[0053] The present invention relates to the adsorption and reduction of ClO4 in water by molybdenum single-atom porous carbon. - A technical solution in the application of has at least the following beneficial effects:

[0054] The molybdenum single-atom porous carbon of the present invention has a highly developed pore structure, which provides a large number of adsorption sites, thereby increasing the adsorption of ClO4 - The dispersion of single molybdenum atoms on the porous carbon surface provides additional active sites, which helps to enhance the adsorption of ClO4 - In addition, molybdenum is an element with catalytic activity, and its single atoms dispersed in porous carbon can effectively absorb ClO4. - The catalytic reaction helps to reduce ClO4 during the adsorption process. - The concentration of can improve the adsorption effect and rate.

[0055] The molybdenum single-atom porous carbon of the present invention has higher chemical and thermal stability through an optimized preparation method and a step of removing residues, which helps to increase the life of the material, enable it to be recycled, reduce costs and reduce dependence on resources.

[0056] According to some embodiments of the present invention, molybdenum single-atom porous carbon is used to adsorb and reduce ClO4 in water. - The method can be: take 50mL10mg / L ClO4 - The solution was placed in a 100 mL beaker and the system was reacted to pH 3 with 1 M hydrochloric acid solution. Then 0.3 g / L of Mo / S single-atom MgO template porous carbon material was added and the reaction was carried out at a stirring speed of 1200 r / min for 10 min. Unless otherwise specified, all operations were carried out at room temperature (20±5°C).

[0057] The fifth aspect of the present invention provides a method for preparing the molybdenum single-atom porous carbon in the presence of trace amounts of ClO4 in water. - Application in detection.

[0058] According to some embodiments of the present invention, molybdenum single-atom porous carbon is used for trace ClO4 in water. - During the detection, the method is as follows: perchlorate was analyzed using a Dionex ICS-600 ion chromatograph (Thermo Fisher Scientific, USA), the analytical column model was AS19 (4 mm × 250 mm), equipped with an AG19 guard column (4 mm × 50 mm), the eluent was KOH, and the eluent flow rate was 1 mL / min. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is the preparation flow chart of molybdenum single-atom porous carbon.

[0060] Figure 2 This is the Raman spectrum of molybdenum single-atom porous carbon.

[0061] Figure 3 This is the result diagram of the effect of Mo doping amount on the adsorption and reduction of perchlorate.

[0062] Figure 4 This is a diagram of the biomimetic catalytic perchlorate oxygen reduction mechanism. DETAILED DESCRIPTION

[0063] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0064] In some embodiments of the present invention, a method for preparing molybdenum single-atom porous carbon is provided, comprising the steps of using MgO nanosheets, mixing them with a precursor solution containing C, S and Mo, drying to obtain a powder, pyrolyzing the powder, and subjecting the pyrolysis product to acid treatment to remove the template and nanoparticles.

[0065] Porous carbon materials are carbon materials with a variety of pore sizes. The main preparation methods include direct carbonization, activation, and template methods. Template methods use nanoporous materials as templates to create porous carbon materials with controllable morphology. These methods include soft templates and hard templates. Soft templates typically employ block copolymer surfactants and metal-organic frameworks.

[0066] Hard templates can be made from zeolites, mesoporous SiO2, MgO, and other materials. MgO templates are inexpensive, have high chemical and thermal stability, do not react with carbon above the carbonization temperature, and are easily removed by washing with dilute acid solutions. Carbon nanomaterials produced using template methods have enormous potential for application in many areas due to their high specific surface area, thermal stability, and controllable pore structure.

[0067] It can be understood that the preparation method of molybdenum single-atom porous carbon of the present invention uses cheap and easily available materials, which reduces the overall processing cost and contributes to the popularization and promotion of the technology.

[0068] The present method for preparing molybdenum monatomic porous carbon utilizes a mixture of MgO nanosheets and a precursor solution to form a porous structure. This porous property is highly beneficial for material applications, particularly in catalysis and adsorption, as it increases the material's surface area and enhances its reactivity.

[0069] The preparation method of molybdenum single-atom porous carbon in the present invention is such that through the pyrolysis process, molybdenum atoms are singly dispersed in the porous carbon material. This single-atom dispersion helps to improve the catalytic activity, reduce the interaction between molybdenum atoms, and thus enhance the catalytic performance of the material.

[0070] In the preparation method of molybdenum single-atom porous carbon in the present invention, the acid treatment step helps to remove templates and nanoparticles, further improving the purity and stability of the porous carbon material. This helps to ensure that the prepared material meets the expected performance requirements.

[0071] The prepared molybdenum single-atom porous carbon in the present invention has potential application fields, especially in catalytic reactions. Molybdenum is a commonly used catalyst, and by embedding its single atoms into the porous carbon structure, its catalytic efficiency and selectivity can be improved while reducing the influence of impurities.

[0072] In some embodiments of the present invention, the preparation method of MgO nanosheets includes: mixing MgO powder with a dispersant, followed by hydrothermal treatment, and then sintering the product after filtration and washing.

[0073] In some embodiments of the present invention, the dispersant includes polyethylene glycol 2000.

[0074] In some embodiments of the present invention, the temperature of the hydrothermal treatment is 160°C to 200°C.

[0075] In some embodiments of the present invention, the temperature of the hydrothermal treatment is about 180°C.

[0076] In some embodiments of the present invention, the time of the hydrothermal treatment is 40h to 60h.

[0077] In some embodiments of the present invention, the time of the hydrothermal treatment is about 48h.

[0078] In some embodiments of the present invention, the sintering method includes: heating up to 600°C to 700°C at a rate of 10°C / min to 20°C / min and holding for 3h to 10h.

[0079] In some embodiments of the present invention, the sintering method can be: heating up to 650°C at a rate of 15°C / min and holding for 5h.

[0080] In some embodiments of the present invention, the preparation method of MgO nanosheets can be:

[0081] Commercial magnesium oxide powder was used as the raw material, and a hydrothermal reaction was assisted by the dispersant polyethylene glycol 2000. 1.0g of MgO powder and 2.1g of polyethylene glycol 2000 were dissolved in 200mL of deionized water, stirred until a suspension formed, and then hydrothermally treated at 180°C for 48h. After filtration, washing, and freeze-drying, the mixture was heated to 650°C in a nitrogen flow (100sccm) at 15°C / min for 5h to obtain MgO nanosheets.

[0082] In some embodiments of the present invention, in the precursor solution, the carbon source includes glucose.

[0083] In some embodiments of the present invention, in the precursor solution, the sulfur source includes dibenzyl disulfide.

[0084] In some embodiments of the present invention, in the precursor solution, the molybdenum source includes sodium molybdate.

[0085] It should be noted that other carbon sources, sulfur sources and molybdenum sources can be used to prepare porous carbon for ClO4 - The removal effect will vary depending on the precursor mixture.

[0086] In some embodiments of the present invention, MgO nanosheets are mixed with a precursor solution containing C, S, and Mo by:

[0087] 2.5g glucose (5mL water) + 1.0g dibenzyl disulfide (20mL ethanol) are mixed first;

[0088] 1 g of the prepared MgO nanosheet template was added;

[0089] 25 mg of sodium molybdate was added, and the mixed solution was dried overnight and ground into powder.

[0090] In some embodiments of the present invention, the pyrolysis method includes: heating to 900° C. to 1000° C. at a rate of 10° C. / min to 20° C. / min under a protective atmosphere, and keeping the temperature for 1 hour to 3 hours.

[0091] In some embodiments of the present invention, the pyrolysis method may be: under protective atmosphere, heating to 950°C at a rate of 15°C / min and holding for 2 hours. Thereafter, the reactor is naturally cooled to room temperature under nitrogen protection, and the resulting product is collected.

[0092] The powder can be placed in a corundum boat for pyrolysis.

[0093] The protective atmosphere may be a nitrogen flow of 100 seem.

[0094] In some embodiments of the present invention, the acid treatment method can be to stir the product with 1.0 mol / L hydrochloric acid for 48 h to remove all templates and nanoparticles.

[0095] In some embodiments of the present invention, the preparation method further includes washing, filtering, and drying the product after acid treatment.

[0096] In some other embodiments of the present invention, a molybdenum single-atom porous carbon prepared by the preparation method of the present invention is provided.

[0097] It can be understood that the molybdenum single-atom porous carbon of the present invention uses inexpensive and easily available materials, reduces the overall processing cost, and helps the popularization and promotion of the technology.

[0098] The molybdenum single-atom porous carbon of the present invention has a wide range of applications, especially in catalysis, adsorption, etc. It has a high specific surface area and high reaction activity.

[0099] In some other embodiments of the present invention, an application of the molybdenum single-atom porous carbon of the present invention in adsorbing and reducing perchlorate in a biomimetic catalytic system is provided.

[0100] It can be understood that the biomimetic catalytic system may be the best candidate for achieving a breakthrough in the technology of catalytic reduction of perchlorate. Although perchlorate is highly inert in the natural environment, microorganisms have evolved a set of precise enzymatic reaction mechanisms for perchlorate reduction under anaerobic conditions. The key active site of perchlorate reductase (PcrAB) is the molybdenum cofactor complex coordinated by pterin (Mo-bisMGD). Specifically, after perchlorate binds to the tetravalent molybdenum (MoⅣ) active site, it is reduced to chlorate (ClO3 - ) through direct oxygen atom transfer (OAT), and at the same time, the tetravalent Mo active site accepts an oxygen atom and is oxidized to a hexavalent molybdenum (MoⅥ) central complex; subsequently, the tetravalent Mo accepts 2e from the respiratory chain - to achieve the transformation from the MoⅥ to the MoⅣ active site. In summary, the redox cycle carried out with the transition metal Mo as the active site makes it possible to reduce and degrade perchlorate through OAT.

[0101] In the biological method for reducing perchlorate, the key active site of the reductase is the molybdenum cofactor complex coordinated by pterin. The biomimetic catalytic system of the present invention, with the transition metal Mo as the active site, performs a redox cycle makes it possible to reduce and degrade perchlorate through OAT.

[0102] In some other embodiments of the present invention, the molybdenum single-atom porous carbon of the present invention is provided for adsorbing and reducing ClO4 in water - .

[0103] It can be understood that the molybdenum single-atom porous carbon of the present invention has a highly developed pore structure, providing a large number of adsorption sites, thereby increasing the adsorption capacity for ClO4 - . The dispersion of molybdenum single atoms on the porous carbon surface provides additional active sites, which helps to enhance the selective adsorption of ClO4 - and improve the adsorption efficiency. In addition, molybdenum is an element with catalytic activity, and its single-atom dispersion in the porous carbon has a positive effect on the degradation of ClO4 - . The catalytic reaction helps to reduce the concentration of ClO4 - during the adsorption process, improving the adsorption effect and rate.

[0104] The molybdenum single-atom porous carbon of the present invention has higher chemical and thermal stability through an optimized preparation method and steps for removing residues, which helps to improve the lifespan of the material, enabling it to be recycled, reducing costs, and decreasing dependence on resources.

[0105] In some embodiments of the present invention, when the molybdenum single-atom porous carbon is used for adsorbing and reducing ClO4 in water - , the method can be as follows: Take 50 mL of 10 mg / L ClO4 - solution in a 100 mL beaker, adjust the reaction pH of the system to 3 with 1 M hydrochloric acid solution, then add 0.3 g / L of the Mo / S single-atom MgO template porous carbon material, and react at a stirring speed of 1200 r / min for 10 min. Unless otherwise specified, all operations are carried out at room temperature (20 ± 5 °C).

[0106] In some other embodiments of the present invention, the molybdenum single-atom porous carbon of the present invention is provided for the detection of trace ClO4 in water - .

[0107] According to some embodiments of the present invention, when the molybdenum single-atom porous carbon is used for the detection of trace ClO4 in water - , the method is as follows: Analyze perchlorate using a Dionex ICS-600 ion chromatograph (Thermo Fisher Scientific, USA). The analytical column model is AS19 (4 mm × 250 mm), equipped with a AG19 guard column (4 mm × 50 mm). The eluent is KOH, and the flow rate of the eluent is 1 mL / min.

[0108] Next, the technical solution of the present invention will be better understood in combination with specific embodiments.

[0109] It should be noted that all reagents in the examples were obtained from commercial channels.

[0110] Example 1

[0111] A method for preparing molybdenum single-atom porous carbon, which uses MgO nanosheets, mixed with a precursor solution containing C, S and Mo, dried to obtain a powder, and pyrolyzed, and the pyrolysis product is acid-treated to remove the template and nanoparticles. The preparation process is as follows: Figure 1 As shown, the specific steps are:

[0112] (1) Preparation of MgO nanosheet template:

[0113] Commercial magnesium oxide powder was used as the raw material, and a dispersant-assisted hydrothermal reaction was performed. 1.0 g of MgO powder and 2.1 g of polyethylene glycol 2000 were dissolved in 200 mL of deionized water. After stirring until a suspension liquid was formed, the mixture was hydrothermally treated at 180 °C for 48 h.

[0114] After filtration, washing, and freeze-drying, the temperature was raised to 650° C. at 15° C. / min in a nitrogen flow (100 sccm) and maintained for 5 h to obtain MgO nanosheets.

[0115] (2) Prepare C\S\Mo precursor solution:

[0116] Mix 2.5 g glucose (5 mL water) and 1.0 g dibenzyl disulfide (20 mL ethanol) first;

[0117] 1 g of the prepared MgO nanosheet template was added;

[0118] 25 mg of sodium molybdate was added, the mixed solution was dried overnight, and ground into powder.

[0119] (3) Pyrolysis: The obtained powder was placed in a corundum boat and heated to 950°C at 15°C / min under a nitrogen flow (100 sccm) for 2 h. The reactor was cooled naturally to room temperature under nitrogen protection, and the obtained product was collected.

[0120] (4) Acid treatment and purification: The product was treated with 1.0 mol / L hydrochloric acid with stirring for 48 h to remove all templates and nanoparticles.

[0121] (5) After washing, filtration, and freeze-drying, molybdenum single-atom porous carbon with 0.3304 wt% Mo was obtained for further characterization and measurement.

[0122] The prepared materials were characterized by Raman spectroscopy. Figure 2 As shown in the figure, as the doping amount of Mo increases, the ratio of the D peak to the G peak of graphene (ID / IG) decreases, indicating that the defects of graphene are reduced and more single atomic Mo is anchored on the oxygen-sulfur doped graphene material.

[0123] Example 2

[0124] The molybdenum monatomic porous carbon containing 0.3304 wt% Mo prepared in Example 1 is used to remove perchlorate, specifically comprising the following steps:

[0125] Step (1): Prepare 50 mL of a 10 mg / L perchlorate water sample and transfer it into a 100 mL beaker;

[0126] Step (2): using 1M hydrochloric acid solution to adjust the system to pH = 3;

[0127] Step (3): Add 0.3 g / L of 0.3304 wt% Mo-containing Mo / S single-atom MgO-templated porous carbon material to the water sample prepared in step (1), and stir at 1200 rpm. Samples were taken at 0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 10 minutes to monitor the perchlorate removal effect.

[0128] Comparative Example 1

[0129] The difference from Example 2 is that the material added in step (3) is molybdenum monatomic porous carbon with 0 wt% Mo, and the other steps are the same.

[0130] Comparative Example 2

[0131] The difference from Example 2 is that the material added in step (3) is molybdenum monatomic porous carbon with 0.8174 wt% Mo, and the other steps are the same.

[0132] Comparative Example 3

[0133] The difference from Example 2 is that the material added in step (3) is molybdenum monatomic porous carbon with 1.2941 wt% Mo, and the other steps are the same.

[0134] Comparative Example 4

[0135] The difference from Example 2 is that the material added in step (3) is molybdenum monatomic porous carbon with 10.3531 wt% Mo, and the other steps are the same.

[0136] Under the same conditions as in Example 2 and Comparative Examples 1 to 4, the removal effect of perchlorate changes over time as shown in the following table: Figure 3 shown.

[0137] It can be seen that as the mass fraction of Mo in the material increases, the molybdenum single-atom porous carbon has a greater - However, when the Mo dosage increases to 10.3531wt%, the removal rate of ClO4 -Removal has no effect at all. The reason is that excessive Mo will agglomerate, instead reducing the number of single-atom Mo sites, that is, ClO4 - The number of oxygen-deprived reduction sites decreases. At the same time, excessive Mo may also react with ClO4 - to compete for adsorption sites and hinder the electron transfer channel.

[0138] The Mo / S single-atom MgO-templated porous carbon material with 0.8174 wt% Mo shows relatively good removal effect on 10 mg / L ClO4 - and can remove nearly 55% of ClO4 in 10 min. - .

[0139] In some embodiments of the present invention, an application of the molybdenum single-atom porous carbon of the present invention in the adsorption and reduction of perchlorate in a biomimetic catalytic system is also provided. The mechanism can be referred to Figure 4 as shown.

[0140] It should be noted that the biomimetic catalytic system may be the best candidate for achieving a breakthrough in the technology of catalytic reduction of perchlorate. Although perchlorate is highly inert in the natural environment, microorganisms have evolved a set of precise enzymatic reaction mechanisms for perchlorate reduction under anaerobic conditions. The key active site of perchlorate reductase (PcrAB) is the molybdenum cofactor complex coordinated by pterin (Mo-bisMGD). Specifically, after perchlorate binds to the tetravalent molybdenum (MoⅣ) active site, it is reduced to chlorate (ClO3 - ) through direct oxygen atom transfer (OAT). At the same time, the tetravalent Mo active site accepts an oxygen atom and is oxidized to a hexavalent molybdenum (MoⅥ) central complex; subsequently, the tetravalent Mo accepts 2e from the respiratory chain - to achieve the transformation from MoⅥ to MoⅣ active site. In short, the redox cycle with transition metal Mo as the active site makes it possible to reduce and degrade perchlorate through OAT.

[0141] The present invention has been described in detail above in conjunction with the embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art.

Claims

1. Application of molybdenum single-atom porous carbon in adsorbing and reducing perchlorate in a biomimetic catalytic system, characterized in that, The preparation method of the molybdenum single-atom porous carbon comprises the following steps: Mix MgO nanosheets with a precursor solution containing C, S, and Mo, dry to obtain a powder and pyrolyze it. After acid-treating the pyrolysis product to remove the template, wash, filter, and dry the product; Among them, the precursor containing C is glucose, the precursor containing S is dibenzyl disulfide, and the precursor containing Mo is sodium molybdate; The pyrolysis method includes: under a protective atmosphere condition, heating to 950 °C - 1000 °C at a rate of 10 °C / min - 20 °C / min, and holding for 1 h - 3 h; The molybdenum single-atom porous carbon is used for adsorbing and reducing perchlorate in a biomimetic catalytic system.

2. The application according to claim 1, wherein The preparation method of the MgO nanosheets includes: mixing MgO powder with a dispersant, performing hydrothermal treatment, and sintering the product after filtration and washing; 3. The application according to claim 2, characterized in that The temperature of the hydrothermal treatment is 160 °C - 200 °C.

4. The application according to claim 2, wherein The time of the hydrothermal treatment is 40 h - 60 h.

5. The application according to claim 2, characterized in that, The sintering method includes: heating to 600 °C - 700 °C at a rate of 10 °C / min - 20 °C / min, and holding for 3 h - 10 h.

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