CN112625256B - Preparation method and denitration application of mesoscale-regulated multilevel core-shell structure bimetal MOF-74(Co-Cu) - Google Patents

Preparation method and denitration application of mesoscale-regulated multilevel core-shell structure bimetal MOF-74(Co-Cu) Download PDF

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CN112625256B
CN112625256B CN202011334275.0A CN202011334275A CN112625256B CN 112625256 B CN112625256 B CN 112625256B CN 202011334275 A CN202011334275 A CN 202011334275A CN 112625256 B CN112625256 B CN 112625256B
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石勇
郭靖
李春艳
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Dalian University of Technology
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Abstract

The invention provides a preparation method and denitration application of a mesoscale regulation and control multilevel core-shell structure bimetal MOF-74 (Co-Cu). The catalyst selects long-chain organic molecular salt containing cobalt to be efficiently coordinated with an organic ligand, special surface treatment is carried out on the long-chain organic molecular salt and the organic ligand, and then the long-chain organic molecular salt and the organic ligand are synthesized and modified in a low-temperature steam environment after crystals are obtained, so that Cu metal nano modified by a surfactant can be automatically grown on the surface of a Co precursor to form a multi-level core-shell structure composite material with different thicknesses. The catalyst prepared by the invention has excellent low-temperature catalytic denitration activity, and the conversion rate of nitrogen oxides in an operation window of 200-275 ℃ reaches more than 96%.

Description

Preparation method and denitration application of mesoscale-regulated multilevel core-shell structure bimetal MOF-74(Co-Cu)
Technical Field
The invention relates to a preparation method of a novel MOF-74(Co-Cu) material with a multi-level core-shell structure and excellent low-temperature CO selective catalytic reduction (CO-SCR) performance. Belongs to the field of novel material design and preparation, and also relates to the practical application of the catalyst in low-temperature flue gas denitration.
Background
Nitrogen oxides (NOx) produced by the combustion of fossil fuels are currently considered a major source of atmospheric pollution, causing various health and environmental related problems such as photochemical smog, acid rain, ozone depletion, and greenhouse effect. The selective catalytic reduction technology is the most widely and effectively denitration means in coal-fired power plants. Conventional NH3In the SCR reaction, the reducing agent NH3High consumption, easy corrosion of equipment and secondary pollutant generation. In addition, CO is generated in the incomplete combustion process, and the product after CO-SCR reaction is CO2And N2And the like, so that the CO is economically feasible to be used as a reducing agent of NO, and the aim of treating wastes with wastes is fulfilled.
In recent years, there have been many catalysts associated with CO-SCR technology. In the initial stage of SCR development, most active phases are made of precious metals, and the precious metals have good high-activity effect at low temperature, but are easily poisoned and aged by flue gas pollution, so that the service life of the catalyst is short, and the economic benefit is low. Therefore, the catalyst is gradually replaced by transition metal, the transition metal is low in price, and the catalyst can achieve higher thermal stability and catalytic activity at low temperature after being modified properly. Research shows that the Ni, Mn, Cu and Co based oxide has excellent CO-SCR activity. In addition, there are studies that demonstrate that there are electronic and geometric effects in the bimetallic catalyst, which promote the interaction between the reactants and the d-band of the active sites, and that when a second metal is added to the catalyst, new active sites are generated due to the geometric effects. Thus, the synergistic effect of the bimetallic action can significantly improve the catalytic activity.
Metal Organic Frameworks (MOFs) are three-dimensional, reticulated porous materials composed of metal ions and organic ligands, the most notable features of these materials are their unique active site structure, large surface area, and sufficient porosity to allow shape and size selectivity. In the MOF material, different metal ions have different effects in increasing catalytic activity, reducing reaction temperature, and increasing stability, so that the performance of the catalyst can be improved by combining different metal ions. As researches prove that the Co-based catalyst and the Cu-based oxide catalyst which exist independently have higher CO-SCR catalytic activity, but the researches on bimetallic MOFs containing cobalt and copper and being applicable to low-temperature CO-SCR are less. The high selectivity of MOFs to NO can be realized by utilizing the synergistic effect of the two metal active centers, the catalytic activity of the MOFs is improved, and the low-temperature denitration treatment of industrial flue gas is realized. However, the conventional synthesis methods reported at present are generally carried out in a solvent environment with low efficiency. The present inventors have also found that inorganic metal salts of Co such as Co (NO) have been commonly used in previous studies3)2·6H2O,CoCl2·6H2O,Co(CH3COO)2·4H2And O is used as a raw material to prepare a Co precursor, and experimental research finds that inorganic salt is easy to cause low deprotonation rate in the reaction process, so that the coordination efficiency of metal and organic ligand is limited, the synthesis rate of the Co precursor is influenced, and the synthesis difficulty and the yield of the bimetallic MOFs material are high. In the previous research, metal nano particles are easy to agglomerate, so that the surface area and active sites are reduced, and the catalytic activity is further reduced. We find that appropriate surfactants are selected for modification by a material surface interface microenvironment regulation method, MOFs can be used as templates for coating on the surface of the material, MOF-74(Co-Cu) with a multi-level hollow core-shell structure is prepared, particle agglomeration can be effectively avoided, and the stability and catalytic activity of the catalyst are improved. The MOF-74(Co-Cu) catalyst which is good in dispersity, high in activity and large in specific surface area and has important application value in the field of low-temperature catalytic denitration is developed at present.
Disclosure of Invention
The invention discloses a preparation method of a novel multi-level hollow core-shell MOF-74(Co-Cu) material based on mesoscale regulation, which is applied to a low-temperature catalytic CO-SCR denitration technology.
The invention determines that the coordination reaction of metal salt and organic ligand can be effectively promoted by adopting long-chain organic molecular salt containing cobalt [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) through a large amount of screening. And the Co precursor is subjected to surface modification by sodium dodecyl diphenyl ether disulfonate to form an organic adsorption layer, the treated Co precursor is used as a core, and the affinity of the metal nano Cu and Co precursor can be improved through the medium action of the adsorption layer.
In addition, researches show that the Cu metal precursor solution which is uniformly dispersed and stable can be prepared by adopting dodecyl dimethyl benzyl ammonium chloride DDBAC as a surfactant, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate as a morphology control agent and fatty alcohol polyoxyethylene ether sodium sulfate as a structure directing agent. Cu metal nano particles self-grow into multi-layer hollow core-shell structures with different thicknesses on the surface of a Co precursor in a low-temperature DMF vapor environment, so that MOF-74(Co-Cu) with uniformity, stability, good selectivity and excellent low-temperature CO-SCR catalytic performance is prepared. According to the invention, by introducing additives DDBAC, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and sodium fatty alcohol polyoxyethylene ether sulfate, the microenvironment of a material surface interface micro-area is reasonably controlled, the MOFs material with a multi-layer structure is prepared, and specific physical and chemical properties are endowed. By controlling the reaction parameters and repeating the experimental steps, the spherical MOF-74(Co-Cu) with multiple layers of uniform and different shell thicknesses can be obtained. Surfactant Dodecyl Dimethyl Benzyl Ammonium Chloride (DDBAC), morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and structure directing agent fatty alcohol polyoxyethylene ether sodium sulfate are used in combination, and good coordination among the surfactant dodecyl dimethyl benzyl ammonium chloride, the morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and the structure directing agent fatty alcohol polyoxyethylene ether sodium sulfate is utilized to improve uniformity, dispersibility and size distribution of the material.
According to the invention, firstly, a Co precursor is prepared by adopting the solvothermal method, then a Cu precursor prepared by using a specific additive is added, and finally, under a steam environment, Cu metal nano particles grow on the surface of the Co precursor to form the multi-level hollow core-shell structure composite material with different thicknesses. Compared with the traditional method, the experimental environment is carried out in a steam environment, so that the self-growth speed of Cu particles on the surface of the Co precursor is greatly improved. In addition, the invention prepares the multi-level hollow core-shell structure MOF-74(Co-Cu) material based on the regulation and control of two mesoscale problems of material surface interface and particle agglomeration.
The technical scheme of the invention is as follows:
a preparation method of a bimetallic MOF-74(Co-Cu) with a mesoscale regulation and control multi-level core-shell structure comprises the following specific steps:
(1) preparation of a Co precursor:
dissolving 2, 5-dihydroxy terephthalic acid in an N-2-methyl pyrrolidone-isopropanol-ultrapure water mixed system to obtain a solution A; dissolving [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) and sodium dodecyl diphenyl ether disulfonate in the solution A, and performing ultrasonic treatment until the cobalt (II) and the sodium dodecyl diphenyl ether disulfonate are completely mixed to obtain a solution B; transferring the solution B into a polytetrafluoroethylene reaction kettle, carrying out solvothermal reaction at 60-150 ℃ for 2-6 hours to obtain a suspension of a Co precursor with a modified surface, carrying out centrifugal separation on a product after the reaction, respectively purifying the separated solid precipitate for 3 times by using N-2-methyl pyrrolidone and ultrapure water, and drying to obtain brick red Co precursor powder with the modified surface;
wherein the addition amount of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) is 0.2-1.8 g;
the volume of the N-2-methyl pyrrolidone-isopropanol-ultrapure water mixed system is 2-2.5 times of the mass of the 2, 5-dihydroxy terephthalic acid, wherein the volume unit is mL, and the mass unit is mg;
the volume ratio of the N-2-methyl pyrrolidone, the isopropanol and the ultrapure water is 6-10:2-6: 1;
the mass ratio of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II), 2, 5-dihydroxy terephthalic acid and sodium dodecyl diphenyl ether disulfonate is 1-6:1-3: 1;
(2) preparing a metal nano Cu precursor solution:
dissolving copper sulfate solid in ultrapure water, and magnetically stirring until the copper sulfate solid is dissolved to obtain a solution C with the concentration of 0.2-1 mol/L; then adding a surfactant DDBAC, a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate, a structure directing agent sodium fatty alcohol-polyoxyethylene ether sulfate, a reducing agent sodium borohydride and ascorbic acid, and magnetically stirring at room temperature until the components are completely mixed to obtain a treated metal nano Cu precursor solution;
wherein the mass ratio of the surfactant DDBAC, the morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and the structure directing agent sodium fatty alcohol ether sulfate is 1:1:1-1:1: 6;
the addition amount of copper sulfate is 0.3-1.2g, and the mass of the copper sulfate is 2-6.5 times of that of DDBAC;
the mass ratio of the sodium borohydride to the ascorbic acid is 5:1-1:1, wherein the mass of the sodium borohydride is 1.82-1.95 times that of copper in the copper sulfate;
(3) preparation of bimetallic MOF-74 (Co-Cu):
adding the surface-modified Co precursor into the treated metal nano Cu precursor solution, magnetically stirring uniformly at room temperature, and centrifugally collecting the mixed solution to obtain a mixed solid of the Co precursor and the treated metal nano Cu precursor solution; pouring 2-8mL of organic solvent into a closed container, placing the obtained solid in the closed container, keeping the solid and the organic solvent out of contact, and placing the closed container in an oven at 80-160 ℃ for heat preservation for 24-72 h; the reaction is carried out in the vapor phase and the steps are repeated 2-5 times; after the reaction is finished, washing the mixture with methanol, and drying the mixture in a vacuum drying oven at the temperature of 60-120 ℃ for 12-36h to obtain a purple MOF-74(Co-Cu) material;
wherein the volume of the metal nano Cu precursor solution is 0.05-0.75 times of the mass of the Co precursor, the unit of the volume is mL, and the unit of the mass is mg.
The organic solvent is one or more of DMF, cyclohexanone and methyl isobutyl ketone.
The application of the mesoscale-controlled multi-level core-shell structure bimetal MOF-74(Co-Cu) in denitration is carried out on NO 500ppm, CO 1000ppm and 5% O2，N2As balance gas, the catalytic performance test is carried out under the condition that the gas flow rate is 200mL/min, and the denitration activity reaches more than 96 percent at the temperature of 200-275 ℃.
Compared with the prior art, the invention has the following beneficial effects:
(1) the invention selects a surfactant Dodecyl Dimethyl Benzyl Ammonium Chloride (DDBAC), a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and a structure directing agent fatty alcohol polyoxyethylene ether sodium sulfate to regulate and control two mesoscale problems of microenvironment of material surface interface and particle agglomeration, so that the prepared multi-level hollow core-shell structure MOF-74(Co-Cu) material avoids the problem of particle agglomeration.
(2) The invention adopts the long-chain organic metal salt containing cobalt, accelerates the coordination rate of the metal salt and the organic ligand, and shortens the time process; the sodium dodecyl diphenyl ether disulfonate is selected to modify the Co precursor, so that the affinity of the metal nano Cu and the Co precursor is increased.
(3) By controlling the synthesis conditions and reaction time of the nanoparticles, multi-level hollow structures with different shell thicknesses can be formed in different areas, so that the specific surface area of the hollow structures is increased to 753.7m 2/g. The performance of the catalyst is tested by CO-SCR catalytic denitration activity, and the denitration activity can reach more than 96% at the temperature of 200-275 ℃, and the selectivity is high.
(4) The invention has the advantages of cheap and easily obtained metal source, high and stable catalytic activity, good catalyst dispersion, environmental protection and convenient recycling. And the nano material mesoscale regulation and control and the flue gas denitration technology are combined, so that an effective way is provided for preparing the novel catalyst.
Drawings
FIG. 1 is a test chart of NO selective catalytic activity of core-shell bimetallic MOF-74(Co-Cu) materials prepared in example 1, example 2, example 3 and example 4 of the present invention.
FIG. 2 is an X-ray crystal diffraction pattern of core-shell bimetallic MOF-74(Co-Cu) materials prepared in examples 1 and 2 of the present invention.
FIGS. 3(a) and 3(b) are scanning electron micrographs of core-shell bimetallic MOF-74(Co-Cu) prepared in examples 1 and 2, respectively, of the present invention at 45000 and 60000 times magnification.
FIG. 4 is a thermogravimetric analysis plot of core-shell bimetallic MOF-74(Co-Cu) materials prepared in example 4 of the present invention over the range of 50-700 ℃.
FIG. 5 is a full spectrum of X-ray photoelectron spectroscopy analysis of the core-shell bimetallic MOF-74(Co-Cu) material prepared in example 3 of the present invention.
FIG. 6 is a diagram of X-ray photoelectron spectroscopy analysis of Co element of the core-shell bimetallic MOF-74(Co-Cu) material prepared in example 3 of the present invention.
FIG. 7 is an infrared spectrum of a core-shell bimetallic MOF-74(Co-Cu) material prepared in example 4 of the present invention at a temperature in the range of 50-300 ℃.
Detailed Description
In order that those skilled in the art will better understand the concept of the present invention, the present invention will be further described in detail with reference to the following examples.
Example 1
The preparation method of the mesoscale-controlled multi-level core-shell structure bimetal MOF-74(Co-Cu) specifically comprises the following steps:
(1) preparation of a Co precursor: dissolving 244mg of 2, 5-dihydroxy terephthalic acid in a total volume of 90mL of a mixed system of N-2-methylpyrrolidone-isopropanol-ultrapure water with a volume ratio of (6:3:1) to obtain a solution A; dissolving 865mg of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) and 128mg of sodium dodecyl diphenyl ether disulfonate in the solution A, and performing ultrasonic treatment for 25min, wherein the ultrasonic treatment frequency is 60KHz, and the power is 180W to obtain a solution B; and transferring the solution B into a 100mL polytetrafluoroethylene reaction kettle, reacting for 4 hours at the reaction temperature of 125 ℃, centrifuging the suspension of the Co precursor with the surface modification for 24 minutes by a centrifuge at the rotating speed of 8000r/min, washing the suspension three times by N-2-methyl pyrrolidone and ultrapure water respectively, and drying to obtain brick red surface-modified Co precursor powder.
(2) Preparing a metal nano Cu precursor solution: dissolving 798mg of copper sulfate solid in 25mL of ultrapure water, and placing the solution on a magnetic stirrer to mix and stir for 33min to obtain a solution C; then adding 624mg of surfactant DDBAC, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and sodium fatty alcohol polyoxyethylene ether sulfate as structure directing agents and 617mg of reducing agent sodium borohydride and ascorbic acid in the mass ratio of (3:1) into the mixture, and stirring the mixture until the mixture is uniformly mixed to obtain the specially treated metal nano Cu precursor solution.
(3) Preparation of MOF-74 (Co-Cu): adding 241mg of surface-modified Co precursor into 32mL of metal nano Cu precursor solution treated by a surfactant DDBAC, a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and a structure directing agent sodium fatty alcohol polyoxyethylene ether sulfate, magnetically stirring at room temperature for 62min, centrifuging the mixed solution at the rotating speed of 8000r/min for 12min, and collecting the mixed solid of the two. Pouring 4mL of DMF organic solvent into a closed container, placing the obtained solid in the closed container, keeping the solid in contact with the DMF solution, placing the closed container in an oven with the temperature of 110 ℃ for heat preservation for 48h, carrying out the reaction in a vapor phase, repeating the steps for 3 times, washing the obtained product with methanol after the reaction is finished, and drying the product in a vacuum drying oven with the temperature of 100 ℃ for 24 h to obtain the purple hollow core-shell structure MOF-74(Co-Cu) material.
In FIG. 1, MOF-74(Co-Cu)1 is an activity curve of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared by the embodiment, and shows excellent catalytic activity within a temperature window of 175-275 ℃, the catalytic activity is as high as 96%, and the reaction temperature window is wide. The material reduces the CO-SCR reaction temperature. Fig. 2 is an X-ray crystal diffraction pattern of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, and the pattern shows that strong and sharp diffraction peaks exist at 2 θ ═ 8.7 °,14.2 °,16.7 ° and 18.2 °, which is consistent with the MOF-74 crystal report in the literature, and thus, the bimetallic MOF-74(Co-Cu) material with a good crystal structure is successfully synthesized. Fig. 3(a) is a scanning electron microscope image of a multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, from which, MOF-74(Co-Cu) is in a regular hollow core-shell spherical structure, and metal nano-Cu ions densely grow on the surface of a Co precursor to form shells with different thicknesses.
Example 2
The preparation method of the mesoscale-controlled multi-level core-shell structure bimetal MOF-74(Co-Cu) specifically comprises the following steps:
(1) preparation of a Co precursor: dissolving 232mg of 2, 5-dihydroxy terephthalic acid in a mixed system of N-2-methyl pyrrolidone-isopropanol-ultrapure water with a volume ratio of (6:2:1) to obtain a solution A, wherein the volume ratio of the total volume of the mixed system is 80 mL; dissolving 576mg of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) and 132mg of sodium dodecyl diphenyl ether disulfonate in the solution A, and performing ultrasonic treatment for 32min, wherein the ultrasonic treatment frequency is 60KHz, and the power is 180W, so as to obtain a solution B; and transferring the solution B into a 100mL polytetrafluoroethylene reaction kettle, reacting for 4 hours at the reaction temperature of 100 ℃, centrifuging the suspension of the Co precursor with the surface modification for 24 minutes by a centrifuge at the rotating speed of 8000r/min, washing the suspension three times by N-2-methyl pyrrolidone and ultrapure water respectively, and drying to obtain brick red surface-modified Co precursor powder.
(2) Preparing a metal nano Cu precursor solution: 672mg of copper sulfate solid is dissolved in 45mL of ultrapure water and placed on a magnetic stirrer to be mixed and stirred for 46min, so that solution C is obtained; and then adding 560mg of surfactant DDBAC, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and a structure directing agent sodium fatty alcohol polyoxyethylene ether sulfate in a total mass ratio of (1:1:3), and reducing agents sodium borohydride and ascorbic acid in a total mass ratio of (4:1) of 528mg, stirring until uniform mixing, and obtaining the specially treated metal nano Cu precursor solution.
(3) Preparation of MOF-74 (Co-Cu): adding 213mg of surface-modified Co precursor into 40mL of metal nano Cu precursor solution treated by a surfactant DDBAC, a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and a structure directing agent sodium fatty alcohol polyoxyethylene ether sulfate, magnetically stirring for 75min at room temperature, centrifuging the mixed solution for 20min at the rotating speed of 8000r/min, and collecting the mixed solid of the two. Pouring 8mL of cyclohexanone organic solvent into a closed container, placing the obtained solid in the closed container, keeping the solid not in contact with the cyclohexanone solution, placing the closed container in an oven at the temperature of 125 ℃ for heat preservation for 48h, carrying out the reaction in a vapor phase, repeating the steps for 3 times, washing the reaction product with methanol after the reaction is finished, and drying the product in a vacuum drying oven at the temperature of 120 ℃ for 32 h to obtain the purple hollow core-shell MOF-74(Co-Cu) bimetallic material.
In FIG. 1, MOF-74(Co-Cu)2 is an activity curve of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, and compared with the activity of the catalyst prepared in example 1, the activity of the catalyst material prepared in this example 2 before 150 ℃ is slightly lower, but the NO conversion rate is relatively close to that in the range of 175-275 ℃. Fig. 2 is an X-ray crystal diffraction pattern of a multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, compared with a diffraction peak spectrum of a catalytic material prepared in example 1, the diffraction peak position of the catalytic material prepared in this example is substantially the same as that of example 1, but the peak value is weaker, which indicates that the catalytic material prepared in example 1 has better crystallinity. Fig. 3(b) is a high-power scanning electron microscope image of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, SEM tests show that the microscopic morphology of the bimetallic MOF-74(Co-Cu) material prepared in this example is similar to that of example 1, the metallic nano-Cu grows in a layered manner with a Co precursor as a core to form a spherical structure, the size is uniform, the dispersibility and uniformity of the bimetallic MOF-74(Co-Cu) are good, and the particle size is small and no obvious agglomeration phenomenon occurs.
Example 3
The preparation method of the mesoscale-controlled multi-level core-shell structure bimetal MOF-74(Co-Cu) specifically comprises the following steps:
(1) preparation of a Co precursor: dissolving 252mg of 2, 5-dihydroxy terephthalic acid in a total volume of 100mL of an N-2-methylpyrrolidone-isopropanol-ultrapure water mixed system in a volume ratio of (6:3:1) to obtain a solution A; dissolving 934mg of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) and 31mg of sodium dodecyl diphenyl ether disulfonate in the solution A, and performing ultrasonic treatment for 32min, wherein the ultrasonic treatment frequency is 60KHz, and the power is 180W, so as to obtain a solution B; and transferring the solution B into a 100mL polytetrafluoroethylene reaction kettle, reacting for 6 hours at the reaction temperature of 135 ℃, centrifuging the suspension of the Co precursor with the surface modification for 30 minutes by a centrifuge at the rotating speed of 8000r/min, washing the suspension three times by N-2-methyl pyrrolidone and ultrapure water respectively, and drying to obtain brick red surface-modified Co precursor powder.
(2) Same as example 1
(3) At the same time carry out 1
In fig. 1, MOF-74(Co-Cu)3 is an activity curve of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, and compared with examples 1 and 2, the material prepared in this example has the best denitration efficiency, which indicates that Co and Cu can better exert a synergistic effect under this implementation condition, reduce the activation energy of Co-SCR reaction, and promote Co-SCR reaction. From the X-ray photoelectron spectroscopy analysis chart of this example of FIG. 5, it can be seen that Co, Cu, O and C elements exist in the bimetallic catalyst. The spectrum of Co 2p in this example in FIG. 6 shows that the two main peaks at 796.5eV and 781.6eV belong to Co2+The two peaks at 801.4 and 785.5eV belong to Co2+In addition, Co can be observed at 780.1eV3+Indicating C in the bimetallic MOF-74(Co-Cu) materialo is mainly composed of Co2+And Co3+In composition, the existence of the Co species is helpful to weaken N-O bonds, promote the decomposition of NO molecules and accelerate the catalytic cycle of CO-SCR.
Example 4
The preparation method of the mesoscale-controlled multi-level core-shell structure bimetal MOF-74(Co-Cu) specifically comprises the following steps:
(1) same as example 1
(2) Same as example 1
(3) Preparation of MOF-74 (Co-Cu): adding 454mg of surface-modified Co precursor into 45mL of metal nano Cu precursor solution treated by a surfactant DDBAC, a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and a structure directing agent sodium fatty alcohol polyoxyethylene ether sulfate, magnetically stirring for 90min at room temperature, centrifuging the mixed solution for 35min at the rotating speed of 8000r/min, and collecting the mixed solid of the two. Pouring 8mL of methyl isobutyl ketone organic solvent into a closed container, placing the obtained solid in the closed container, keeping the solid not in contact with the methyl isobutyl ketone solution, placing the closed container in an oven with the temperature of 125 ℃ for heat preservation for 48h, carrying out the reaction in a vapor phase, repeating the steps for 3 times, washing the reaction product with methanol after the reaction is finished, and drying the product in a vacuum oven with the temperature of 120 ℃ for 32 h to obtain the purple hollow core-shell structure bimetallic MOF-74(Co-Cu) material.
In FIG. 1, MOF-74(Co-Cu)4 is an activity curve of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in this example, and the catalytic activity effect of the material prepared in this example is similar to that of example 1. FIG. 4 is a thermogravimetric analysis diagram of the multi-layered core-shell bimetallic MOF-74(Co-Cu) material prepared in this example, in which there are three main weight loss intervals within the range of 50-700 ℃, and the removal of water molecules adsorbed in the catalytic material is mainly performed at 50-120 ℃; the weight loss at 350-420 ℃ is attributed to the removal of organic solvent molecules coordinated on the CUS and residual solvent molecules in the material pore channels; the organic framework of the 420-550 ℃ bimetallic MOF-74(Co-Cu) material decomposes and collapses, gradually losing activity. The thermal stability of the catalyst is an important index for evaluating the catalyst, and the multi-level core-shell structure bimetal MOF-74(Co-Cu) prepared by the method has stabilityGood and has wider application prospect. FIG. 7 is an infrared spectrum of 1475cm of the multi-layered core-shell bimetallic MOF-74(Co-Cu) material prepared in this example－1The characteristic peaks in the vicinity represent NO2－Species, 1020cm－1The characteristic peak at (A) represents CO3 2－Species, CO3 2－The acidity of the surface of the catalyst can be increased, the adsorption of NO and CO molecules is facilitated, and the intermediate active species can contribute to the improvement of the catalytic activity of CO-SCR.
Example 5
And (3) activity test: about 0.2g of the multi-level core-shell structure bimetallic MOF-74(Co-Cu) material prepared in example 1, example 2, example 3 and example 4 is respectively taken and loaded into a quartz tube with the inner diameter of 8mm, before the test, the catalyst is pretreated for 10h at 200 ℃ in the atmosphere of N2, the initial reaction gas composition is 500ppm NO,1000ppm CO and N2 are balanced, the total flow rate is 200mL/min, and the space velocity (GHSV) is 30000h－1The temperature is regulated and controlled by a temperature control heating instrument at the heating rate of 3 ℃/min, the concentration of NO is recorded every time the temperature is increased by 25 ℃ at 50-300 ℃, and the result is recorded after the reading of an on-line flue gas analyzer is stable, and is shown in figure 1.

Claims (3)

1. A preparation method of bimetallic MOF-74(Co-Cu) with a mesoscale regulation and control multi-level core-shell structure is characterized by comprising the following steps:
(1) preparation of a Co precursor:
dissolving 2, 5-dihydroxy terephthalic acid in an N-2-methyl pyrrolidone-isopropanol-ultrapure water mixed system to obtain a solution A; dissolving [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II) and sodium dodecyl diphenyl ether disulfonate in the solution A, and performing ultrasonic treatment until the cobalt (II) and the sodium dodecyl diphenyl ether disulfonate are completely mixed to obtain a solution B; transferring the solution B into a polytetrafluoroethylene reaction kettle, carrying out solvothermal reaction at 60-150 ℃ for 2-6 hours to obtain a suspension of a Co precursor with a modified surface, carrying out centrifugal separation on a product after the reaction, respectively purifying the separated solid precipitate for 3 times by using N-2-methyl pyrrolidone and ultrapure water, and drying to obtain brick red Co precursor powder with the modified surface;
wherein the volume of the N-2-methylpyrrolidone-isopropanol-ultrapure water mixed system is 2-2.5 times of the mass of the 2, 5-dihydroxy terephthalic acid, the unit of the volume is mL, and the unit of the mass is mg;
the volume ratio of the N-2-methyl pyrrolidone, the isopropanol and the ultrapure water is 6-10:2-6: 1;
the mass ratio of [5,10,15, 20-tetra (4-methoxyphenyl) porphyrin ] cobalt (II), 2, 5-dihydroxy terephthalic acid and sodium dodecyl diphenyl ether disulfonate is 1-6:1-3: 1;
(2) preparing a metal nano Cu precursor solution:
dissolving copper sulfate solid in ultrapure water, and magnetically stirring until the copper sulfate solid is dissolved to obtain a solution C with the concentration of 0.2-1 mol/L; then adding a surfactant DDBAC, a morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate, a structure directing agent sodium fatty alcohol-polyoxyethylene ether sulfate, a reducing agent sodium borohydride and ascorbic acid, and magnetically stirring at room temperature until the components are completely mixed to obtain a treated metal nano Cu precursor solution;
wherein the mass ratio of the surfactant DDBAC, the morphology control agent 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol ethoxylate and the structure directing agent sodium fatty alcohol ether sulfate is 1:1:1-1:1: 6;
the mass of the copper sulfate is 2-6.5 times of that of the DDBAC;
the mass ratio of the sodium borohydride to the ascorbic acid is 5:1-1:1, wherein the mass of the sodium borohydride is 1.82-1.95 times that of copper in the copper sulfate;
(3) preparation of bimetallic MOF-74 (Co-Cu):
adding the surface-modified Co precursor into the treated metal nano Cu precursor solution, magnetically stirring uniformly at room temperature, and centrifugally collecting the mixed solution to obtain a mixed solid of the Co precursor and the treated metal nano Cu precursor solution; pouring 2-8mL of organic solvent into a closed container, placing the obtained solid in the closed container, keeping the solid and the organic solvent out of contact, and placing the closed container in an oven at 80-160 ℃ for heat preservation for 24-72 h; the reaction is carried out in the vapor phase and the steps are repeated 2-5 times; after the reaction is finished, washing the mixture with methanol, and drying the mixture in a vacuum drying oven at the temperature of 60-120 ℃ for 12-36h to obtain a purple MOF-74(Co-Cu) material;
wherein the volume of the metal nano Cu precursor solution is 0.05-0.75 times of the mass of the Co precursor, the unit of the volume is mL, and the unit of the mass is mg.
2. The preparation method of the mesoscale-controlled multi-level core-shell bimetallic MOF-74(Co-Cu) according to claim 1, wherein the organic solvent is one or a mixture of more than two of DMF, cyclohexanone and methyl isobutyl ketone.
3. The application of the mesoscale-controlled multi-level core-shell structure bimetallic MOF-74(Co-Cu) prepared by the preparation method of claim 1 or 2 in denitration is characterized in that the mesoscale-controlled multi-level core-shell structure bimetallic MOF-74(Co-Cu) is applied to denitration at 500ppm of NO,1000ppm of CO and 5% of O2，N2As balance gas, the catalytic performance test is carried out under the condition that the gas flow rate is 200mL/min, and the denitration activity reaches more than 96 percent at the temperature of 200-275 ℃.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103752169A (en) * 2014-01-10 2014-04-30 大连理工大学 Metal-organic frame material Cu-BTC for removing nitric oxide with selective catalytic reduction method
JPWO2016204301A1 (en) * 2015-06-18 2018-04-05 国立大学法人九州大学 Composite materials, photon upconversion materials and photon upconverters
CN109701657A (en) * 2019-01-15 2019-05-03 大连理工大学 A kind of synthetic method and its application of MOF-74-NiCo material
CN110302840A (en) * 2019-06-03 2019-10-08 大连理工大学 A kind of MnO2The preparation method and application of/Cu-Al-BTC ternary metal organic framework material

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103752169A (en) * 2014-01-10 2014-04-30 大连理工大学 Metal-organic frame material Cu-BTC for removing nitric oxide with selective catalytic reduction method
JPWO2016204301A1 (en) * 2015-06-18 2018-04-05 国立大学法人九州大学 Composite materials, photon upconversion materials and photon upconverters
CN109701657A (en) * 2019-01-15 2019-05-03 大连理工大学 A kind of synthetic method and its application of MOF-74-NiCo material
CN110302840A (en) * 2019-06-03 2019-10-08 大连理工大学 A kind of MnO2The preparation method and application of/Cu-Al-BTC ternary metal organic framework material

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"双金属MOF-74-CoMn 催化剂的制备及其CO选择性催化还原技术应用";武卓敏等;《化学学报》;20190708;第77卷;第758-764页 *

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