Porous LDH nano composite material and preparation method thereof
By introducing microbial bacteria into the preparation of LDH, inhibiting the stacking of LDH sheets and forming a porous structure, the problem of limited specific surface area and catalytic performance of LDH materials in the prior art is solved, and higher specific surface area and catalytic performance are achieved.
Patent Information
- Application Number
- CN202411736270.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-02-28
AI Technical Summary
The prior art is difficult to form porous structures on layered double hydroxide (LDH) nanosheets, resulting in limited specific surface area and catalytic properties.
By introducing microbial bacteria to participate in the preparation of LDH, the interaction between the surfactant of the bacteria and the metal ions of the LDH is used to inhibit the stacking of sheets and promote the formation of porous structures.
The specific surface area, porosity and catalytic properties of LDH materials are improved, so that they can perform better performance in the fields of catalysis and adsorption.
Smart Images
Figure CN119524820A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of composite materials, and in particular to a porous LDH nanocomposite material and a preparation method thereof. Background Art
[0002] Layered double hydroxide (LDH) is a class of inorganic materials with a special layered structure, which is widely used in catalysis, adsorption, drug delivery and other fields. The general chemical formula of layered double hydroxide (LDH) is [M 2+ 1-x M 3+ x (OH) 2 ] x + (An - ) x / n·mH 2 O, where M 2+ and M 3+ Represent divalent and trivalent metal ions, An - is an anion, and x represents the ratio of divalent and trivalent metals. The tunability of the interlayer spacing and composition of LDH gives it excellent anion exchange capacity and thermal stability. However, the layered structure of LDH often leads to stacking of its sheets through interactions such as electrostatic attraction, hydrogen bonding, and van der Waals forces, thereby reducing its specific surface area, limiting the exposure of the active sites of the material, and thus affecting its catalytic and adsorption properties.
[0003] Although there have been studies on improving the performance of LDH by changing the chemical synthesis method, such as preparing different morphologies (such as nanoflowers, nanotubes, nanorods, etc.), or reducing the stacking of sheets by introducing spatial barriers, these methods often have problems such as complex operation and high cost, and fail to form a porous structure on the LDH nanosheets, which is crucial for enhancing the specific surface area and reaction performance of LDH. Therefore, how to effectively reduce the interlayer stacking of LDH and form a porous structure on its sheets is still a technical problem that needs to be solved urgently. Summary of the invention
[0004] The purpose of the present invention is to solve the defects of the above-mentioned prior art and provide a porous LDH nanocomposite material and a preparation method thereof, by introducing microbial cells to participate in the preparation of LDH, inhibiting the stacking of LDH sheets and promoting the formation of a porous structure, thereby improving the specific surface area, porosity and catalytic performance of the LDH material.
[0005] According to one object of the present invention, the present invention provides a method for preparing a porous LDH nanocomposite material, comprising the following steps:
[0006] 0.05 g of dry bacterial cells were added to 20 mL of deionized water and sonicated in an ultrasonic processor for 20 min;
[0007] Add 6 mmol Zn(NO 3 ) 2 (1.7849 g) and 2 mmolAl(NO 3 ) 3 (0.7503 g) was dissolved in 130 mL of water and stirred for 30 minutes until it was completely dissolved;
[0008] 2.4 g of urea was added to the solution, stirred for 5 minutes, and placed in an oil bath at 120° C. for reflux reaction for 24 hours.
[0009] After the reaction, the LDH precipitate was washed by centrifugation and dried in an oven at 80°C;
[0010] The TiO 2 Composite to obtain LDH / TiO 2 Composite materials can be fired or not to obtain the final product.
[0011] Beneficial effects:
[0012] The LDH composite material prepared by the method of the present invention has a high specific surface area and a good pore structure, and can effectively improve its performance in catalysis, adsorption, etc. Through the participation of microbial cells, the surface active components thereof interact with the metal ions of LDH, and the morphology and structure of LDH are effectively controlled during the synthesis process, so that its sheet structure is more dispersed, the stacking is reduced, and a porous structure can be formed on the LDH sheet, thereby enhancing its specific surface area and the exposure of active sites. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is the LDH / TiO 2 Scanning electron microscope (SEM) images of the composite material;
[0014] Figure 2 The specific surface area test results of the examples of the present invention and the control materials are shown in FIG.
[0015] Figure 3 The figure is a test result of specific surface area of the embodiment of the present invention and the reference material after calcination;
[0016] Figure 4 The pore size distribution diagram of the embodiment of the present invention and the control material under adsorption;
[0017] Figure 5 It is the pore size distribution diagram of the embodiment of the present invention and the control material under desorption. DETAILED DESCRIPTION
[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0019] Example 1
[0020] The present invention provides a method for preparing a porous LDH nanocomposite material, comprising the following steps:
[0021] Step 1: Sonication of the cells
[0022] Take 0.05g of dry bacteria, add it to 20mL of deionized water, and use an ultrasonic processor to ultrasonicate at 60Hz for 20 minutes. The surface active components and water molecules of the bacteria can help stabilize the metal ions in the synthesis reaction and prevent them from forming aggregates or irregular precipitation.
[0023] Step 2: Dissolution of metal salts
[0024] In a reaction vessel, 6 mmol Zn(NO 3 ) 2 (1.7849 g) and 2 mmol Al(NO 3 ) 3 (0.7503 g), add 130 mL of water and stir for 30 minutes until completely dissolved. This step is the main metal ion source for LDH.
[0025] Step 3: Urea addition and reflux reaction
[0026] 2.4 g of urea was added to the solution and stirred for 5 minutes to make the urea evenly distributed. The solution was transferred to an oil bath at 120°C for reflux reaction for 24 hours. Urea provides alkalinity in the reaction, which promotes the 2+ and Al 3 + The ions form a layered structure.
[0027] Step 4: Centrifugation and drying
[0028] After the reaction is completed, the LDH precipitate is separated by centrifugation, washed with deionized water to remove impurities, and dried in an oven at 80° C. to obtain the final LDH material.
[0029] Step 5: LDH and TiO 2 complex
[0030] The prepared LDH reacts with a n-butyl titanate precursor solution under hydrothermal conditions to prepare a composite material. The composite material can be further calcined or not calcined to adjust its pore structure and surface properties.
[0031] The SEM image of the LDH composite material prepared by the above method shows that it has good dispersibility and pore structure, and a high specific surface area, and is suitable for use as a catalyst, adsorbent and other fields.
[0032] like Figure 1 As shown, Figure 1 LDH / TiO 2 Scanning electron microscope (SEM) images of the composite material. Figure 1 The surface morphology and pore structure of the material are shown in Figure 2, indicating that it has good dispersibility and porosity. The control LDH was prepared under the same conditions, only with salt and urea, without the addition of bacteria, and there was no pore structure on the LDH nanosheet.
[0033] Figure 2 This is the specific surface area test result diagram. Figure 2 This indicates that the LDH composite material prepared by the method has a larger adsorption capacity and is suitable for providing more active sites in the catalytic and adsorption processes. The adsorption capacity of the LDH prepared by the present invention is significantly enhanced.
[0034] like Figure 3 As shown, the adsorption amount of the embodiment of the present invention after calcination is relatively enhanced, and a hysteresis loop phenomenon occurs, which is a typical mesoporous material.
[0035] like Figure 4 As shown, it is the pore size distribution diagram under adsorption. It can be seen that the pore size distribution of this work is larger and wider.
[0036] like Figure 5 As shown, this is the pore size distribution diagram under desorption. It can be seen that the pore size distribution of this work is larger and wider.
[0037] According to the pore volume data, the catalyst (t-Plot micropore volume, 0.000729cm 3 / g) is also higher than the control (0.000378cm 3 / g) is higher.
[0038] The LDH composite material prepared by the method of the present invention has a high specific surface area and a good pore structure, and can effectively improve its performance in catalysis, adsorption, etc. Through the participation of microbial cells, the surface active components thereof interact with the metal ions of LDH, and the morphology and structure of LDH are effectively controlled during the synthesis process, so that its sheet structure is more dispersed, the stacking is reduced, and a porous structure can be formed on the LDH sheet, thereby enhancing its specific surface area and the exposure of active sites.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a porous LDH nanocomposite material, characterized in that: The steps include: S1. Add 0.05 g of dry bacteria into 20 mL of deionized water and ultrasonicate for 20 minutes. S2, add 6mmol Zn(NO3)2 and 2mmol Al(NO3)3 and dissolve them in 130mL water, and stir for 30 minutes; S3, add 2.4 g of urea to the solution, stir for 5 minutes, and then reflux in an oil bath at 120°C for 24 hours; S4, centrifugal washing, drying at 80°C to obtain LDH material; S5. Hydrothermally react LDH and TiO2 to obtain a LDH / TiO2 composite material.
2. The method according to claim 1, wherein the microbial cell is a microorganism whose surface active component can help stabilize metal ions and prevent them from forming irregular aggregates.
3. The method according to claim 1, wherein the LDH composite material has a high specific surface area and porosity, and is suitable for catalysis and adsorption applications.
4. The method according to claim 1, wherein the ratio of the reaction bacteria, the amount of divalent and trivalent salts, and urea is 0.05 g, 6:2, 40 mmol, the temperature is 120°C, and the reaction time is 24 hours.
5. A porous LDH nanocomposite material, characterized in that: The invention is prepared by the method according to any one of claims 1 to 4.