Method for regulating morphology of nitrogen-rich metal organic framework material by using organic template

Abstract

The present application relates to a kind of methods for regulating the morphology of nitrogen-rich metal organic framework material using organic template agent, belong to the technical field of micro-nano material synthesis.The purpose of the present application is to solve the problems of single morphology, uneven particle size distribution and other problems of nitrogen-rich MOFs micro-nano particles obtained by the prior art, and to provide a method for regulating the morphology of nitrogen-rich metal organic framework material using organic template agent;By using organic template agent, the reaction solvent, reaction temperature and reaction time are controlled, the ratio of organic ligand, metal salt and organic template agent is controlled, so that the morphology and size of MOFs micro-nano particles are effectively controlled, and spherical, flower-like, snowflake-like, interpenetrating, cubic or sheet-like morphology can be obtained, with high yield, high repeatability, and morphology transformation of MOFs material is simultaneously controlled.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of micro-nano material synthesis, and relates to a method for regulating the morphology of nitrogen-rich metal organic framework materials by using an organic template agent. BACKGROUND

[0002] In recent years, the functionalization of micro-nano materials has attracted more and more attention of researchers, and the morphology and size of micro-nano materials have important influences on various performances thereof, so more and more attention is paid to the controllable preparation of micro-nano materials with different morphologies and sizes. On the other hand, metal organic framework materials (MOFs) have attracted extensive research attention, and their structural diversity, porosity, large specific surface area and other physical and chemical properties have been used in various applications. For example, due to the high ratio of exposed active sites to volume and fast adsorption / desorption kinetics, MOF micro-nano particles show higher performance in the fields of sensing, catalysis and biomedicine than in bulk state. In addition, the controllable assembly of MOF micro-nano particles can produce synergies between discrete structural units, thereby obtaining functionalized materials with different properties. For example, by regulating the grain size of MOFs to change the adsorption rate, nano-MOFs can be made into thin films, which are applied in the fields of catalysis, chemical sensors and the like by virtue of their developed pore structure and chemical composition. Therefore, the size and shape control of MOF materials is a key condition for material development, design and application.

[0003] MOF materials with different shapes exhibit different properties, and thus have different application ranges. For example, spherical MOF materials exhibit excellent specificity and can be used as carriers or catalysts; when the size of MOF materials matches the light wave, the materials can exhibit diffraction or interference effects. Therefore, regulating the shape and size of MOF materials can regulate the function of the materials and expand the application range of the materials. At present, since MOF micro-nano particles are difficult to separate by size after synthesis, limiting the size and shape of nano-particles during the synthesis process is considered to be an effective strategy for producing uniform micro-nano particles. At present, researchers have developed a large number of bottom-up and top-down synthesis methods, such as co-precipitation method, solvent (water) thermal method, microwave heating method and microemulsion method. Among the developed synthesis methods, the use of template agents to induce self-assembly to obtain ideal nano structures provides a reference for preparing MOF micro-nano particles with uniform size, controllable morphology, complex structure and morphology. SUMMARY

[0004] The application aims to solve the problems of single morphology and uneven particle size distribution of the existing nitrogen-rich MOFs micro-nanoparticles, and provides a method for regulating the morphology of nitrogen-rich metal organic framework materials by using an organic template agent.

[0005] To achieve the above-mentioned purpose, the technical scheme of the application is as follows:

[0006] The method for regulating the morphology of nitrogen-rich metal organic framework materials by using an organic template agent comprises the following steps:

[0007] (1) Dissolve azido triazole and copper salt in water respectively, and stir to completely dissolve to form solution A and solution B; dissolve the organic template agent in ethanol, and stir to completely dissolve to form solution C;

[0008] (2) Add solution B to solution A, mix and stir uniformly, and mix thoroughly, then heat for a period of time, and then add solution C to the mixed solution, mix and stir uniformly, and continue to heat for a period of time;

[0009] (3) Let the mixed solution stand for a period of time, and centrifuge, wash and dry the crystals to obtain the crystals of nitrogen-rich metal organic framework materials with various morphologies and sizes.

[0010] The water is deionized water with a purity of 18 MΩ·cm or above, and the ethanol is 95% anhydrous ethanol.

[0011] Preferably, the molar ratio of the copper salt, azido triazole and organic template agent in the preparation process is controlled to be 1:(0.01-1):(10-200).

[0012] Preferably, the copper salt is one or any mixture of the following: copper nitrate hexahydrate, copper acetate dihydrate, copper chloride dihydrate, copper perchlorate hexahydrate, copper tetrafluoroborate hexahydrate or copper sulfate pentahydrate.

[0013] Preferably, the organic template agent is one or any mixture of the following: cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfonate (SDS), cationic polyacrylamide (CPAM, Mw: 10,000, 100,000, 500,000, 1,800,000), polyacrylamide PH III (Mw: 200-14,000,000), polyethylene glycol, polyvinyl alcohol, polyethyleneimine, poly(4-styrene sulfonic acid), polyaniline, polyacrylonitrile, and polyvinylpyrrolidone.

[0014] Preferably, the reaction heating temperature of step (2) is 40-100℃, and the reaction time is 0.5-4h.

[0015] Preferably, the stirring speed of steps (1) and (2) is 300-800rpm.

[0016] Preferably, the standing time of the mixed solution of step (3) is 4-24h.

[0017] Preferably, the centrifugal speed of step (3) is 3000-10000r / min, and the centrifugal time is 5-20min; the washing is washing with deionized water for 3-5 times; and the drying is placing in a drying oven at 50-150℃ for 8-36h.

[0018] Preferably, the morphology of the prepared nitrogen-rich metal organic framework material micro-nanoparticles is spherical, flower-shaped, snowflake-shaped, interpenetrated type, cubic or flaky, etc.

[0019] Beneficial effects

[0020] The method for regulating the crystal morphology and morphology transformation of metal organic framework material by using a template provided by the application has the advantages of cheap and easily available raw materials, low cost, simple and easy-to-operate synthesis method, good repeatability, and the ability to synthesize a variety of morphological crystals with high purity and uniform size. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0022] Figure 2 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0023] Figure 3 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0024] Figure 4 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0025] Figure 5 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0026] Figure 6 (a) is a scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nanoparticles obtained in Example 1; (b) is an enlarged picture of the particles in (a).

[0027] Figure 7 Optical microscope bright field picture of the sheet-like nitrogen-rich MOFs obtained in Example 7.

[0028] Figure 8 Scanning electron microscope picture of the nitrogen-rich MOFs crystals obtained in Example 8 under different proportions of ethanol and water.

[0029] Figure 9 Blocky nitrogen-rich MOFs material obtained by reacting azido-triazole (ATRZ) with copper nitrate in Control Group 1. DETAILED DESCRIPTION

[0030] The application will be further described in detail below with reference to examples.

[0031] Example 1

[0032] (1) 164 mg of azido-triazole was dissolved in 25 mL of water to form solution A, and 295.5 mg of copper nitrate hexahydrate was dissolved in 5 mL of water to form solution B; 455 mg of cetyltrimethylammonium bromide (CTAB) was dissolved in 20 mL of ethanol, and stirred until completely dissolved to form solution C;

[0033] (2) Solution B was added to solution A, and stirred until uniformly mixed. After being heated at 60°C for 2.5 h, solution C was added to the mixed solution, and stirred until uniformly mixed. The heating was continued for another 2.5 h.

[0034] (3) The mixed solution was left to stand for 18 h, and crystals were precipitated. After centrifugation, washing and drying, spherical nitrogen-rich MOFs micro-nano particles were obtained.

[0035] (4) Figure 1 (a) and (b) are scanning electron microscope pictures of the spherical nitrogen-rich MOFs micro-nano particles obtained in this example.

[0036] Example 2

[0037] (1) 164 mg of azido-triazole was dissolved in 25 mL of water to form solution A, and 295.5 mg of copper nitrate hexahydrate was dissolved in 5 mL of water to form solution B; 455 mg of cetyltrimethylammonium bromide (CTAB) was dissolved in 20 mL of ethanol, and stirred until completely dissolved to form solution C;

[0038] (2) Solution B was added to solution A, and stirred until uniformly mixed. After being heated at 60°C for 2.5 h, solution C was added to the mixed solution, and stirred until uniformly mixed. The heating was continued for another 2.5 h.

[0039] (3) The above mixed solution was left to stand for 18 h, and crystals were precipitated. After centrifugation, washing and drying, spherical nitrogen-rich MOFs micro-nano particles were obtained.

[0040] (4) Figure 2 The scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nano particles obtained in this example is shown.

[0041] Example 3

[0042] (1) 164 mg of azido triazole was dissolved in 25 mL of water to form solution A, and 295.5 mg of copper nitrate hexahydrate was dissolved in 5 mL of water to form solution B. 200 mg of cetyltrimethylammonium bromide (CTAB) was dissolved in 20 mL of ethanol, and stirred until completely dissolved to form solution C;

[0043] (2) Solution B was added to solution A, and stirred until completely mixed. After heating at 60°C for 2.5 h, solution C was added to the above mixed solution, and stirred until completely mixed. Heating was continued for 2.5 h.

[0044] (3) The above mixed solution was left to stand for 18 h, and crystals were precipitated. After centrifugation, washing and drying, spherical nitrogen-rich MOFs micro-nano particles were obtained.

[0045] (4) Figure 3 The scanning electron microscope picture of the spherical nitrogen-rich MOFs micro-nano particles obtained in this example is shown.

[0046] Example 4

[0047] (1) 164 mg of azido triazole was dissolved in 25 mL of water to form solution A, and 295.5 mg of copper nitrate hexahydrate was dissolved in 5 mL of water to form solution B. 1000 mg of polyacrylamide PHIII was dissolved in 20 mL of ethanol, and stirred until completely dissolved to form solution C;

[0048] (2) Solution B was added to solution A, and stirred until completely mixed. After heating at 40°C for 2.5 h, solution C was added to the above mixed solution, and stirred until completely mixed. Heating was continued for 2.5 h.

[0049] (3) The above mixed solution was left to stand for 24 h, and crystals were precipitated. After centrifugation, washing and drying, snowflake-shaped nitrogen-rich MOFs material was obtained.

[0050] (4) Figure 4 The optical microscope bright field picture of the snowflake-shaped nitrogen-rich MOFs micro-nano particles obtained in this example is shown.

[0051] Example 5

[0052] (1) 164 mg azido dissolved in 25 mL of water to form solution A, 295.5 mg copper nitrate hexahydrate dissolved in 5 mL of water to form solution B; 500 mg polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol, and stirred to completely dissolve to form solution C;

[0053] (2) Solution B was added to solution A, and stirred to mix evenly, and after sufficient mixing, heated at 40°C for 2.5 h, and then solution C was added to the above mixed solution, and stirred to mix evenly, and heated for another 2.5 h;

[0054] (3) The above mixed solution was allowed to stand for 24 h, and crystals were precipitated, and centrifuged, washed, and dried to obtain the interpenetrated nitrogen-rich MOFs material.

[0055] (4) Figure 5 It is the optical microscope bright field picture of the interpenetrated nitrogen-rich MOFs obtained in this example.

[0056] Example 6

[0057] (1) 164 mg azido dissolved in 25 mL of water to form solution A, 370.5 mg copper perchlorate hexahydrate dissolved in 5 mL of water to form solution B; 500 mg polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol, and stirred to completely dissolve to form solution C;

[0058] (2) Solution B was added to solution A, and stirred to mix evenly, and after sufficient mixing, heated at 40°C for 2.5 h, and then solution C was added to the above mixed solution, and stirred to mix evenly, and heated for another 2.5 h;

[0059] (3) The above mixed solution was allowed to stand for 24 h, and crystals were precipitated, and centrifuged, washed, and dried to obtain the interpenetrated nitrogen-rich MOFs material.

[0060] (4) Figure 6 It is the optical microscope bright field picture of the interpenetrated nitrogen-rich MOFs obtained in this example.

[0061] Example 7

[0062] (1) 164 mg azido dissolved in 25 mL of water to form solution A, 345 mg copper tetrafluoroborate hexahydrate dissolved in 5 mL of water to form solution B; 500 mg polyvinyl pyrrolidone (PVP) was dissolved in 20 mL of ethanol, and stirred to completely dissolve to form solution C;

[0063] (2) Solution B is added to solution A, mixed and stirred uniformly, and after sufficient mixing, heated at 40°C for 2.5h, and then solution C is added to the above mixed solution, mixed and stirred uniformly, and heated for another 2.5h;

[0064] (3) The above mixed solution is allowed to stand for 24h, and crystals are precipitated, centrifuged, washed, and dried to obtain a sheet-shaped nitrogen-rich MOFs material.

[0065] (4) Figure 7 It is an optical microscope bright field picture of the sheet-shaped nitrogen-rich MOFs obtained in this example.

[0066] Example 8

[0067] (1) The concentration of azido triazole is 0.02mol / L, the concentration of copper nitrate hexahydrate is 0.02mol / L, the concentration of cetyltrimethylammonium bromide (CTAB) is 0.025mol / L, and the volume of the mixed solution is 50mL.

[0068] (2) The EtOH volume ratio of water / ethanol solvent in the mixed solution is adjusted to 0%, 4%, 25%, 35%, 50%, 60%, and 100% to perform the morphology conversion experiment of ATRZ-Cu.

[0069] (3) The reaction is performed according to step (2) of Example 1.

[0070] (4) The above mixed solution is allowed to stand for 18h, and crystals are precipitated, centrifuged, washed, and dried to obtain spherical nitrogen-rich MOFs micro-nano particles.

[0071] (5) Figure 8 It is a scanning electron microscope picture of the nitrogen-rich MOFs crystals obtained in this example under the condition of different proportions of ethanol and water.

[0072] Control group 1

[0073] (1) 164mg of azido triazole is dissolved in 25mL of water to form solution A, and copper nitrate hexahydrate is dissolved in 5mL of water to form solution B; solution B is added to solution A, mixed and stirred uniformly, and after sufficient mixing, heated at 60°C for 6h;

[0074] (3) The above mixed solution is allowed to stand for 6h, and crystals are precipitated, centrifuged, washed, and dried to obtain a block-shaped nitrogen-rich MOFs material.

[0075] (4) Figure 9 It is a block-shaped nitrogen-rich MOFs material obtained by the reaction of azido triazole (ATRZ) and copper nitrate in this example.

[0076] In conclusion, the invention includes but is not limited to the embodiments described above, any equivalents thereto or modifications made thereon, which come within the scope of the invention as defined by the following claims.

Claims

1. A method for regulating the morphology of a nitrogen-rich metal-organic framework material using an organic template agent, characterized in that: By using organic template agent, adjusting reaction solvent, reaction temperature and reaction time, controlling the ratio of organic ligand, metal salt and organic template agent, the morphology and size of MOFs micro-nanoparticles are effectively controlled, and nitrogen-rich metal organic framework materials with high yield and high repeatability in spherical, flower-like, snowflake-like, interpenetrated, cubic or sheet-like morphology are obtained. The preparation method comprises the following steps: Step one, azido triazole and copper salt are dissolved in water respectively to form solution A and solution B; the organic template agent is dissolved in ethanol, stirred to completely dissolve to form solution C; Step two, solution B is added to solution A, mixed and stirred uniformly, heated for a period of time, then solution C is added to the mixed solution, mixed and stirred uniformly, and heated for a period of time to obtain solution D; the molar ratio of the copper salt, azido triazole and organic template agent is 1: (0.01-1) : (10-200) ; Step three, solution D is left to precipitate crystals, and after centrifugation, washing and drying, crystals of nitrogen-rich metal organic framework materials with various morphologies and sizes are obtained.

2. The method for regulating the morphology of nitrogen-rich metal organic framework materials by using organic templates according to claim 1, wherein: The temperature in step two is 40-100 DEG C, and the time is 0.5-4 h. 3.The method of claim 1, wherein the method comprises: adjusting the concentration of the organic template agent to be 0.1-0.5 g / L; adjusting the pH value of the reaction solution to be 6.5-7.5; adjusting the reaction temperature to be 80-100 ℃; and adjusting the reaction time to be 24-48 h. The solution D in step three is left to stand for 4-24 h. 4.The method of claim 1, wherein the method comprises: adjusting the concentration of the organic template agent to be 0.1-0.5 g / L; adjusting the pH value of the reaction solution to be 6.5-7.5; adjusting the reaction temperature to be 80-100 ℃; and adjusting the reaction time to be 24-48 h. The centrifugal speed in step three is 3000-10000 r / min, and the centrifugal time is 5-20 min; the drying is performed by placing in a drying oven at 50-150 DEG C for 8-36 h. 5.The method of claim 1, wherein the method is characterized in that: The water is deionized water with a purity of 18 MΩ·cm or above, and the ethanol used is 95% anhydrous ethanol. 6.The method of claim 1, wherein the method is characterized in that: The copper salt is one or a mixture of any of the following: copper nitrate hexahydrate, copper acetate dihydrate, copper chloride dihydrate, copper perchlorate hexahydrate, copper tetrafluoroborate hexahydrate or copper sulfate pentahydrate. 7.The method of claim 1, wherein the method is characterized in that: The organic template agent is one or a mixture of any of the following: cetyltrimethylammonium bromide, sodium dodecylsulfonate, cationic polyacrylamide, polyethylene glycol, polyvinyl alcohol, polyethyleneimine, poly (4-styrene sulfonic acid), polyaniline, polyacrylonitrile and polyvinylpyrrolidone.

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