Process for the steam-assisted one-step synthesis of hierarchically porous hkust-1 materials
By using a steam-assisted one-step synthesis method, multi-level porous HKUST-1 was prepared in the same container using a steam etchant, which solved the problems of cumbersome operation and high cost of traditional methods, and realized efficient synthesis and industrial production.
Patent Information
- Application Number
- CN202310904522.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-21
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2043-07-21
AI Technical Summary
Existing technologies make it difficult to efficiently synthesize HKUST-1 materials with both micropore-mesopore or micropore-macropore structures. Traditional methods are cumbersome and costly, which is not conducive to industrial production.
A steam-assisted one-step synthesis method was adopted, in which copper source and pyromellitic acid were dissolved in solvent, and etchant vapor was used to react with the precursor solution in the same container to form hierarchical pores HKUST-1. The mesopore size was adjusted by controlling the reaction temperature and time.
The efficient synthesis of hierarchical pore HKUST-1 was achieved, shortening the preparation cycle and reducing costs. Furthermore, the mesopore size can reach 30 nm, making it suitable for industrial production.
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Figure CN116836405B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of porous materials, in particular to a method for synthesizing hierarchical pore HKUST-1 material by steam-assisted one-step. BACKGROUND
[0002] Metal-organic frameworks (MOFs) are porous materials formed by self-assembly of inorganic metal (or metal clusters) nodes and organic ligands into periodic porous frameworks. They usually have the advantages of high porosity, low crystal density and adjustable pore size, and have great potential in the fields of catalysis, adsorption separation, sensing, etc. Among the currently disclosed MOFs materials, most of them are microporous, and only a few of them have mesopores or macropores. In practical applications, although microporous MOFs have high selectivity in separating specific gas components, the active sites of microporous MOFs are usually limited in micropores, which seriously limits the internal mass transfer rate of microporous MOFs in catalysis and adsorption separation processes, thereby greatly limiting the practical application of MOFs materials.
[0003] Cu3(BTC)2, also known as HKUST-1 type metal-organic framework, is a coordination polymer self-assembled from binuclear copper clusters and trimesic acid. Traditional HKUST-1 material only has micropores. In order to make it have the advantages of mesopores and macropores, and reduce the mass transfer resistance of guest molecules, researchers have been committed to introducing mesopores or macropores into its structure, and preparing HKUST-1 material with micropore-mesopore, micropore-macropore or micropore-mesopore-macropore composite pore size.
[0004] The existing methods for preparing hierarchical pore HKUST-1 or other hierarchical pore MOFs are template method and etching method. The template method needs to use surfactants or block copolymers as template agents. The pores of the synthesized MOFs material are easy to be filled with template agent molecules, so that the framework cavities are reduced or occupied, and the MOFs structure is easy to collapse in the process of removing the template agent. The traditional etching method needs to synthesize microporous MOFs first, and then obtain hierarchical pore MOFs by etching agent post-treatment. This method usually needs to carry out the synthesis process and the etching post-treatment process step by step to prepare the hierarchical pore structure, which has long preparation period, complicated operation and high cost, and is not conducive to industrialized production.
[0005] Therefore, the present application is proposed. SUMMARY
[0006] The application aims to provide a method for steam-assisted one-step synthesis of hierarchical pore HKUST-1 material, which can make the synthesis process and the etchant post-processing process simultaneously carried out in the same container, one-pot preparation of HKUST-1 with hierarchical pore structure, shortening of the preparation period, simple operation, low cost and facilitation of industrial production; the HKUST-1 prepared by the method has hierarchical pore structure and high mesopore volume, and the mesopore diameter can reach 30 nm.
[0007] In order to achieve the above-mentioned purpose of the application, the following technical scheme is adopted:
[0008] The method for steam-assisted one-step synthesis of hierarchical pore HKUST-1 material comprises the following steps:
[0009] (1) dissolving a copper source and a trimesic acid in a solvent to prepare a precursor solution;
[0010] (2) placing the precursor solution, an etchant and an adsorbent in different placement areas in the same reactor respectively, keeping the precursor solution, the etchant and the adsorbent from contacting each other, and the steam in the reactor can flow between the placement areas to realize steam phase reaction and steam etching;
[0011] (3) sealing the reactor in step (2) and heating to react, and the obtained solid product is washed, filtered and dried to obtain HKUST-1 with hierarchical pores.
[0012] Preferably, the reactor is provided with a first placement area, a second placement area and a third placement area, the precursor solution, the etchant and the adsorbent are respectively located in the first placement area, the second placement area and the third placement area, and the first placement area is located in the second placement area.
[0013] More preferably, the second placement area is located in the third placement area.
[0014] Preferably, the etchant is a liquid.
[0015] More preferably, the boiling point of the solvent is lower than that of the etchant.
[0016] Preferably, the solvent comprises anhydrous ethanol and / or deionized water.
[0017] More preferably, the volume ratio of the anhydrous ethanol to the deionized water is 2:1 to 1:2.
[0018] Preferably, the etchant is pure acetic acid.
[0019] More preferably, the volume ratio of the solvent to the pure acetic acid is (0.1-10):1.
[0020] Preferably, the molar ratio of the copper source to the trimesic acid is 1:1-3:1.
[0021] Preferably, the molar concentration of the trimesic acid in the precursor solution is 0.07-0.1 mol / L.
[0022] Preferably, the copper source comprises at least one of copper nitrate, copper sulfate, copper chloride and copper acetate.
[0023] More preferably, the copper source is copper acetate monohydrate.
[0024] Preferably, the adsorbent comprises at least one of molecular sieve, activated carbon and silica gel.
[0025] More preferably, the adsorbent is Na-4A molecular sieve.
[0026] More preferably, the mass ratio of the trimesic acid to the Na-4A molecular sieve is 1:(500-1000).
[0027] Preferably, in step (3), the temperature of the heating reaction is 90-140℃, and the time of the heating reaction is 6h-24h.
[0028] More preferably, the temperature of the heating reaction is 100-120℃.
[0029] Preferably, in step (3), the prepared solid product is washed with anhydrous ethanol, and the washing is performed for three times.
[0030] Preferably, in step (3), the drying is natural drying, and the drying time is 6-12h.
[0031] Compared with the prior art, the present application has the following beneficial effects:
[0032] (1) The present application uses pure acetic acid as the etchant, and in the early stage of the reaction, the precursor solution, liquid acetic acid and the adsorbent do not contact each other, the substances in the precursor solution perform the solvothermal reaction, the solvent gradually volatilizes during the heating reaction, and the adsorbent is used to adsorb the volatilized vapor, so that the solvent continuously volatilizes, in the later stage of the reaction, the solvent in the precursor solution completely volatilizes, the vapor phase reaction is performed, and the acetic acid is evaporated to form acetic acid vapor under heat, so as to etch the HKUST-1 to form a hierarchical pore structure, the synthesis process and the etching process are simultaneously performed in the same container, the HKUST-1 with the hierarchical pore structure is prepared by one-pot method, the preparation period is shortened, the operation is simple, the cost is low, and the industrialized production is facilitated.
[0033] (2) Compared with the liquid etchant etching, the amount of the vapor etchant is small.
[0034] (3) The method of the present application can adjust the pore size of the mesopore by reasonably controlling the reaction temperature, reaction time and the amount of acetic acid, and the mesopore size of the prepared HKUST-1 can reach 30 nm. BRIEF DESCRIPTION OF DRAWINGS
[0035] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.
[0036] Figure 1 A schematic diagram of one-step synthesis of hierarchical pore HKUST-1 provided by the embodiments of the present application;
[0037] Figure 2 Wide-angle X-ray diffraction patterns of samples prepared in Examples 1-4 and Comparative Examples 1-2 of the present application;
[0038] Figure 3 Scanning electron microscope images of hierarchical pore HKUST-1 prepared in Example 1 of the present application;
[0039] Figure 4 N2 adsorption-desorption isotherm (77K) of hierarchical pore HKUST-1 prepared in Example 1 of the present application, the curve where the solid points are located represents the adsorption curve, and the curve where the hollow points are located represents the desorption curve;
[0040] Figure 5 Pore size distribution diagram of hierarchical pore HKUST-1 prepared in Example 1 of the present application;
[0041] Figure 6 Scanning electron microscope images of hierarchical pore HKUST-1 prepared in Example 2 of the present application;
[0042] Figure 7 N2 adsorption-desorption isotherm (77K) of hierarchical pore HKUST-1 prepared in Example 2 of the present application, the curve where the solid points are located represents the adsorption curve, and the curve where the hollow points are located represents the desorption curve;
[0043] Figure 8 Pore size distribution diagram of hierarchical pore HKUST-1 prepared in Example 2 of the present application;
[0044] Figure 9 Scanning electron microscope images of hierarchical pore HKUST-1 prepared in Example 3 of the present application;
[0045] Figure 10N2adsorption-desorption isotherm (77 K) of the hierarchically porous HKUST-1 prepared in Example 3, the curve with solid dots represents the adsorption curve, and the curve with hollow dots represents the desorption curve;
[0046] Figure 11 Pore size distribution of the hierarchically porous HKUST-1 prepared in Example 3;
[0047] Figure 12 Scanning electron micrograph of the hierarchically porous HKUST-1 prepared in Example 4;
[0048] Figure 13 N2adsorption-desorption isotherm (77 K) of the hierarchically porous HKUST-1 prepared in Example 4, the curve with solid dots represents the adsorption curve, and the curve with hollow dots represents the desorption curve;
[0049] Figure 14 Pore size distribution of the hierarchically porous HKUST-1 prepared in Example 4;
[0050] Figure 15 Scanning electron micrograph of sample E prepared in Comparative Example 1;
[0051] Figure 16 N2adsorption-desorption isotherm (77 K) of sample E prepared in Comparative Example 1, the curve with solid dots represents the adsorption curve, and the curve with hollow dots represents the desorption curve;
[0052] Figure 17 Scanning electron micrograph of sample F prepared in Comparative Example 2;
[0053] Figure 18 N2adsorption-desorption isotherm (77 K) of sample F prepared in Comparative Example 2, the curve with solid dots represents the adsorption curve, and the curve with hollow dots represents the desorption curve. DETAILED DESCRIPTION
[0054] The technical solutions of the present application will be described clearly and completely in combination with the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, rather than all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. The specific conditions are not specified in the embodiments, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased on the market. In addition, the terms "first", "second", "third", "fourth" and the like are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0055] The application provides a method for synthesizing a hierarchical HKUST-1 material by one-pot vapor-assisted method, which comprises the following steps:
[0056] (1) dissolving a copper source and a trimesic acid in a solvent to obtain a precursor solution;
[0057] (2) placing the precursor solution, an etchant and an adsorbent in different placement zones in the same reactor respectively, and keeping the precursor solution, the etchant and the adsorbent from contacting each other, and the vapor in the reactor can flow between the placement zones to realize vapor-phase reaction and vapor etching;
[0058] (3) sealing the reactor in step (2) and heating to react, and then washing, filtering and drying the obtained solid product to obtain the hierarchical HKUST-1.
[0059] In the method, the precursor solution is used for synthesizing the HKUST-1, the etchant is used for etching the prepared HKUST-1 to form a hierarchical structure, and the adsorbent is used for adsorbing the volatilized vapor in the reaction process to ensure continuous evaporation of the solvent, so that the etchant vapor can enter the placement zone where the HKUST-1 is located to etch the HKUST-1 in the later stage of the reaction, and in addition, the adsorbent can also avoid condensation of the vapor in the cooling process, so that the obtained product is in a solid state; the reactor can be divided into multiple placement zones by means of setting baffles, or the multiple placement zones can be formed by placing multiple open containers in the reactor, so as to ensure that the precursor solution, the liquid etchant and the solid adsorbent do not contact each other in the initial state, and the hierarchical HKUST-1 is prepared by one-pot method through vapor-phase reaction and vapor etching.
[0060] The method of the application can realize simultaneous synthesis and etchant post-processing in the same container, and the hierarchical HKUST-1 is prepared by one-pot method, so that the preparation period is shortened, the operation is simple, the cost is low, and the industrial production is facilitated; the HKUST-1 prepared by the method has a hierarchical structure and a high mesopore volume, and the mesopore diameter can reach 30 nm.
[0061] In some preferred embodiments of the application, the reactor is provided with a first placement zone, a second placement zone and a third placement zone, the precursor solution, the etchant and the adsorbent are respectively located in the first placement zone, the second placement zone and the third placement zone, and the first placement zone is located in the second placement zone, for example, the first placement zone and the second placement zone can be a coaxial cylindrical structure, so that the precursor solution is located in the middle of the etchant, to ensure uniform distribution of the etchant vapor around the HKUST-1 and improve the etching effect.
[0062] In some preferred embodiments of the present application, the second placement zone is located in the third placement zone.
[0063] As shown in the figure, in some preferred embodiments of the present application, the reactor is a stainless steel reaction kettle with a polytetrafluoroethylene lining, a first open bottle is placed in the polytetrafluoroethylene lining, a second open bottle is placed in the first open bottle, the inner space of the second open bottle is the first placement zone for holding the precursor solution, the annular space between the second open bottle and the first open bottle is the second placement zone for holding the etchant, and the annular space between the first open bottle and the polytetrafluoroethylene lining is the third placement zone for holding the adsorbent. Figure 1
[0064] In some preferred embodiments of the present application, the etchant is a liquid, and in a heated state, the etchant can volatilize to form etchant vapor for steam etching of the prepared HKUST-1.
[0065] In some preferred embodiments of the present application, the boiling point of the solvent is lower than that of the etchant, so that the solvent volatilizes preferentially, and after the solvent is completely volatilized, etchant vapor can enter the placement zone where the HKUST-1 is located to etch the HKUST-1, thereby avoiding the etchant being adsorbed by the adsorbent too early, resulting in insufficient etchant vapor in the later stage of the reaction to achieve the etching effect.
[0066] In some preferred embodiments of the present application, the solvent includes anhydrous ethanol and / or deionized water.
[0067] In some preferred embodiments of the present application, the volume ratio of the anhydrous ethanol to the deionized water is 2:1 to 1:2, for example, any one value or a range value composed of any two point values in 2:1, 1.5:1, 1:1, 1:1.5, and 1:2.
[0068] In some preferred embodiments of the present application, the etchant is pure acetic acid, the boiling point of acetic acid is 117.9℃, which is higher than the boiling points of anhydrous ethanol and deionized water, and under the action of heating, acetic acid volatilizes to etch the HKUST-1 formed in the first placement zone. By reasonably selecting the etchant and the reaction solvent, synthesis and etching can be simultaneously performed in the same reactor to realize one-pot preparation of HKUST-1 material with hierarchical pores.
[0069] In some preferred embodiments of the present application, the volume ratio of the solvent to the pure acetic acid is (0.1-10):1, for example, any one value or a range value consisting of any two values selected from the group consisting of 0.1:1, 0.15:1, 0.2:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 2:1, 3:1, 5:1 and 10:1. Reasonable control of the amount of solvent and acetic acid can improve the etching effect of the hierarchical pores.
[0070] In some preferred embodiments of the present application, the molar ratio of the copper source to the trimesic acid is 1:1-3:1, for example, any one value or a range value consisting of any two values selected from the group consisting of 1:1, 1.5:1, 2:1 and 3:1.
[0071] In some preferred embodiments of the present application, the molar concentration of the trimesic acid in the precursor solution is 0.07-0.1 mol / L, for example, any one value or a range value consisting of any two values selected from the group consisting of 0.07 mol / L, 0.08 mol / L, 0.09 mol / L and 0.10 mol / L.
[0072] In some preferred embodiments of the present application, the copper source comprises at least one of copper nitrate, copper sulfate, copper chloride and copper acetate, and more preferably, the copper source is copper acetate monohydrate.
[0073] In some preferred embodiments of the present application, the adsorbent comprises at least one of molecular sieve, activated carbon and silica gel.
[0074] In some preferred embodiments of the present application, the adsorbent is Na-4A molecular sieve.
[0075] In some preferred embodiments of the present application, the mass ratio of the trimesic acid to the Na-4A molecular sieve is 1:(500-1000), for example, any one value or a range value consisting of any two values selected from the group consisting of 1:500, 1:600, 1:700, 1:800, 1:900 and 1:1000.
[0076] In some preferred embodiments of the present application, in step (3), the temperature of the heating reaction is not lower than the boiling point of the solvent, so as to make the solvent in the precursor solution evaporate completely, facilitating the vapor etching in the later stage of the reaction, but the temperature of the reaction should not be too high, so as to avoid the rapid reaction of the precursor and the rapid evaporation of the solvent, which may result in the reduction of the crystallinity of the product. The reaction temperature is preferably 90-140°C, for example, any one of 90°C, 100°C, 110°C, 120°C, 130°C and 140°C or a range value formed by any two of them. The time of the heating reaction is 6-24h, for example, any one of 6h, 12h, 18h and 24h or a range value formed by any two of them. By synergistically adjusting the reaction temperature, the reaction time and the amount of acetic acid, the pore size of the mesopore formed can be adjusted.
[0077] In some preferred embodiments of the present application, the temperature of the heating reaction in step (3) is 100-120°C.
[0078] In some preferred embodiments of the present application, in step (3), the prepared solid product is washed with anhydrous ethanol, and the washing is performed for three times.
[0079] In some preferred embodiments of the present application, in step (3), the drying is natural drying at room temperature, and the drying time is 6-12h, for example, any one of 6h, 8h, 10h and 12h or a range value formed by any two of them.
[0080] Some embodiments of the present application will be described in detail below in conjunction with specific application examples. The raw materials used in the examples, such as the materials without special instructions, can be purchased on the market.
[0081] Example 1
[0082] 0.086g of copper acetate monohydrate and 0.06g of trimesic acid were dissolved in a mixed solution of 2mL of anhydrous ethanol and 2mL of deionized water, and then ultrasonic treatment was performed for 10min to obtain a precursor solution. The prepared precursor solution was placed in a second open bottle. A stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 0.4mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing the pure acetic acid was placed into the polytetrafluoroethylene liner containing the Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing the pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle. The reaction kettle was sealed and placed in an oven at 120°C for heating reaction for 12h. The product was washed with anhydrous ethanol for three times, and then filtered and naturally dried for 6h to obtain a hierarchical pore HKUST-1, which was marked as sample A.
[0083] Example 2
[0084] 0.086 g copper acetate monohydrate and 0.06 g of trimesic acid were dissolved in a mixed solution of 2 mL of anhydrous ethanol and 2 mL of deionized water, and then ultrasonic was applied for 10 min to obtain a precursor solution, and the prepared precursor solution was placed in a second open bottle; a stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30 g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 0.4 mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing pure acetic acid was placed into the polytetrafluoroethylene liner containing Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle, the reaction kettle was sealed and placed in an oven at 100°C for heating reaction for 12 h, the product was washed with anhydrous ethanol for three times, and then naturally dried for 6 h after filtration to obtain hierarchical HKUST-1, which was marked as sample B.
[0085] Example 3
[0086] 0.086 g copper acetate monohydrate and 0.06 g of trimesic acid were dissolved in a mixed solution of 2 mL of anhydrous ethanol and 2 mL of deionized water, and then ultrasonic was applied for 10 min to obtain a precursor solution, and the prepared precursor solution was placed in a second open bottle; a stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30 g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 0.4 mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing pure acetic acid was placed into the polytetrafluoroethylene liner containing Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle, the reaction kettle was sealed and placed in an oven at 100°C for heating reaction for 12 h, the product was washed with anhydrous ethanol for three times, and then naturally dried for 6 h after filtration to obtain hierarchical HKUST-1, which was marked as sample B.
[0087] Example 4
[0088] A mixture of 0.042 g of copper acetate monohydrate and 0.03 g of trimesic acid was dissolved in a mixture of 0.5 mL of absolute ethanol and 1 mL of deionized water, and then ultrasonicated for 10 min to obtain a precursor solution, and the prepared precursor solution was placed in a second open bottle; a stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30 g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 10 mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing pure acetic acid was placed into the polytetrafluoroethylene liner containing Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle, the reaction kettle was sealed, and was placed in an oven at 100°C for heating reaction for 18 h, the product was washed with absolute ethanol for three times, and was naturally dried for 6 h after filtration to obtain hierarchical HKUST-1, which was marked as sample D.
[0089] Comparative example 1
[0090] A mixture of 0.042 g of copper acetate monohydrate and 0.03 g of trimesic acid was dissolved in a mixture of 0.5 mL of absolute ethanol and 1 mL of deionized water, and then ultrasonicated for 10 min to obtain a precursor solution, and the prepared precursor solution was placed in a second open bottle; a stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30 g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 10 mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing pure acetic acid was placed into the polytetrafluoroethylene liner containing Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle, the reaction kettle was sealed, and was placed in an oven at 100°C for heating reaction for 18 h, the product was washed with absolute ethanol for three times, and was naturally dried for 6 h after filtration to obtain hierarchical HKUST-1, which was marked as sample D.
[0091] Comparative example 2
[0092] A mixture of 0.042 g of copper acetate monohydrate and 0.03 g of trimesic acid was dissolved in a mixture of 0.5 mL of absolute ethanol and 1 mL of deionized water, and then ultrasonicated for 10 min to obtain a precursor solution, and the prepared precursor solution was placed in a second open bottle; a stainless steel reaction kettle with a polytetrafluoroethylene liner was taken, 30 g of Na-4A molecular sieve was added into the polytetrafluoroethylene liner, 10 mL of pure acetic acid was taken and added into a first open bottle, the first open bottle containing pure acetic acid was placed into the polytetrafluoroethylene liner containing Na-4A molecular sieve, the second open bottle containing the precursor solution was placed into the first open bottle containing pure acetic acid, and the polytetrafluoroethylene liner was placed into the stainless steel reaction kettle, the reaction kettle was sealed, and was placed in an oven at 100°C for heating reaction for 18 h, the product was washed with absolute ethanol for three times, and was naturally dried for 6 h after filtration to obtain hierarchical HKUST-1, which was marked as sample D.
[0093] Performance testing experiment example
[0094] (i) The crystal structures of the samples prepared in Examples 1 to 4 and Comparative Examples 1 to 2 of this invention were characterized using a D8-ADVANCE X-ray diffractometer manufactured by Bruker GmbH, Germany.
[0095] (ii) The samples prepared in Examples 1 to 4 and Comparative Examples 1 to 2 were characterized using a SU-8010 scanning electron microscope (Hitachi, Japan).
[0096] (III) Nature of the channel
[0097] The pore structures of the samples prepared in Examples 1-4 and Comparative Examples 1-2 of this invention were characterized using a TriStarⅡ3020 surface area analyzer manufactured by Micro Systems, Inc.
[0098] Results Analysis
[0099] like Figure 2 As shown, the characteristic peaks of the wide-angle X-ray diffraction patterns of the samples prepared in Examples 1-4 and Comparative Examples 1-2 are basically consistent with the simulated characteristic peaks of HKUST-1 material. Samples A, B, C, D, E and F prepared in Examples 1-4 and Comparative Examples 1-2 all showed strong characteristic diffraction peaks of HKUST-1 metal-organic framework, indicating that HKUST-1 was successfully synthesized in Examples 1-4 and Comparative Examples 1-2.
[0100] like Figures 3-5 As shown, the scanning electron microscope image of sample A reveals intergranular macropores. The N2 adsorption-desorption isotherm of sample A shows a type I adsorption isotherm at a pressure of P / P0 < 0.01, indicating a sharp increase in adsorption capacity and suggesting that sample A has a microporous structure. A type IV adsorption hysteresis loop appears at a relative pressure of around 0.4, which is a typical feature of mesoporous materials in N2 adsorption-desorption curves, indicating that sample A prepared in Example 1 contains a mesoporous structure. The pore size distribution diagram shows that sample A has mesopores of approximately 12 nm.
[0101] like Figures 6-8 As shown, the scanning electron microscope image of sample B reveals intergranular macropores. The N2 adsorption-desorption isotherm of sample B shows a type I adsorption isotherm at a pressure of P / P0 < 0.01, indicating a sharp increase in adsorption capacity and suggesting that sample B has a microporous structure. A type IV adsorption hysteresis loop appears at a relative pressure of around 0.4, which is a typical feature of mesoporous materials in N2 adsorption-desorption curves, indicating that sample B prepared in Example 2 contains a mesoporous structure. The pore size distribution diagram shows that sample B has mesopores of approximately 30 nm.
[0102] likeFigures 9-11 As shown in the SEM image of sample C, intercrystalline accumulation macropores can be observed, and the N2 adsorption-desorption isotherm of sample C shows type I adsorption isotherm at P / P0<0.01, and the adsorption amount sharply rises, indicating that sample C has a microporous structure; a type IV adsorption hysteresis loop appears at a relative pressure of about 0.4, which is a typical feature of mesoporous materials in N2 adsorption-desorption curves, indicating that sample C prepared in example 3 contains mesoporous structures, and from the pore size distribution graph, it can be seen that sample C has mesopores of about 22 nm.
[0103] As shown in the SEM image of sample D, mesopores and intercrystalline accumulation macropores can be observed, and the N2 adsorption-desorption isotherm of sample D shows type I adsorption isotherm at P / P0<0.01, and the adsorption amount sharply rises, indicating that sample D has a microporous structure; a type IV adsorption hysteresis loop appears at a relative pressure of about 0.4, which is a typical feature of mesoporous materials in N2 adsorption-desorption curves, indicating that sample D prepared in example 4 contains mesoporous structures, and from the pore size distribution graph, it can be seen that sample D has mesopores of about 30 nm. Figures 12-14 As shown in the SEM image of sample E, no mesopores and macropores can be observed, and the N2 adsorption-desorption isotherm of sample E has no hysteresis loop and does not form mesopores, because the reaction temperature is low at 80℃, and the amount of acetic acid vapor is insufficient.
[0104] Figures 15-16 As shown in the SEM image of sample F, the crystallinity of sample F is poor, and no hysteresis loop is obtained, and no mesoporous structure is formed, because the reaction temperature is too high at 150℃, and the precursor reacts and evaporates too quickly, resulting in poor crystallinity of MOFs, and too much acetic acid vapor, resulting in a large decrease in BET.
[0105] As shown in the SEM image of sample F, the crystallinity of sample F is poor, and no hysteresis loop is obtained, and no mesoporous structure is formed, because the reaction temperature is too high at 150℃, and the precursor reacts and evaporates too quickly, resulting in poor crystallinity of MOFs, and too much acetic acid vapor, resulting in a large decrease in BET. Figures 17-18 The pore property results of samples A-F are shown in Table 1, and from Table 1, it can be seen that the hierarchical pore HKUST-1 material prepared in examples 1-4 has a high mesopore volume.
[0106] Table 1 Pore property results of samples A-F
[0107]
[0108]
[0109] Although the present application has been illustrated and described with reference to the specific embodiments, it should be clear that the above-mentioned embodiments are merely preferred examples of the present application, and are used to explain the technical solutions of the present application, but are not used to limit the present application; it should be understood by those skilled in the art that the technical solutions recorded in the above-mentioned embodiments can be modified, or some or all of the technical features can be replaced equivalently, without departing from the spirit and scope of the present application; and these modifications or replacements do not make the nature of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application; therefore, this means that all these replacements and modifications within the scope of the present application are included in the appended claims.
Claims
1. A method for one-step steam-assisted synthesis of hierarchical porous HKUST-1 material, characterized in that, The method comprises the following steps: (1) dissolving a copper source and trimesic acid in a solvent to obtain a precursor solution; (2) placing the precursor solution, an etchant and an adsorbent in different placement zones in the same reactor, respectively, and keeping the precursor solution, the etchant and the adsorbent from contacting each other, and the vapor in the reactor can flow between the placement zones to realize vapor phase reaction and vapor etching; the boiling point of the solvent is lower than that of the etchant; the etchant is pure acetic acid; (3) sealing the reactor in step (2) and heating at 90-140℃ for 6-24h to obtain a solid product, which is washed, filtered and dried to obtain HKUST-1 with hierarchical pores.
2. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The reactor is provided with a first placement zone, a second placement zone and a third placement zone, and the precursor solution, the etchant and the adsorbent are respectively placed in the first placement zone, the second placement zone and the third placement zone, and the first placement zone is located in the second placement zone.
3. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The solvent comprises anhydrous ethanol and / or deionized water.
4. The method of claim 3, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The volume ratio of the anhydrous ethanol to the deionized water is 2:1-1:
2.
5. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by The volume ratio of the solvent to the pure acetic acid is (0.1-10):
1.
6. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The molar ratio of the copper source to the trimesic acid is 1:1-3:
1.
7. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The molar concentration of trimesic acid in the precursor solution is 0.07-0.1mol / L.
8. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The copper source comprises at least one of copper nitrate, copper sulfate, copper chloride and copper acetate.
9. The method of claim 1, wherein the vapor-assisted one-step synthesis of hierarchical HKUST-1 material is characterized by, The adsorbent comprises at least one of molecular sieve, activated carbon and silica gel.