GdCo-MOF / BiOBr composite material as well as preparation method and application thereof
By constructing a Z-shaped heterojunction of GdCo-MOF/BiOBr composite material, the problems of high recombination rate of photogenerated carriers and narrow visible light response range of existing photocatalysts were solved, achieving efficient degradation of antibiotics and dyes in water.
Patent Information
- Application Number
- CN202510959361.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-10-28
Smart Images
Figure CN120838477A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of photocatalyst materials technology, specifically relating to a GdCo-MOF / BiOBr composite material, its preparation method, and its application. Background Technology
[0002] Antibiotic pollution has become a pressing ecological and public health problem in global aquatic environments. Fluoroquinolone antibiotics, represented by norfloxacin, exhibit extremely high stability due to the presence of aromatic rings and conjugated systems in their molecular structure, making them difficult to degrade. Traditional physical, chemical, or biological treatment methods have limited efficiency in removing these pollutants and often generate toxic intermediates. Photocatalytic oxidation technology has gradually gained widespread attention due to its green, environmentally friendly, and sustainable advantages. However, existing semiconductor photocatalysts such as TiO2 and g-C3N4 suffer from weak visible light absorption and high photogenerated carrier recombination rates, hindering efficient and deep degradation.
[0003] Metal-organic frameworks (MOFs) offer an ideal platform for developing advanced photocatalytic systems due to their highly tunable pore structure, large specific surface area, and abundant active sites. However, single MOFs often suffer from high photogenerated carrier recombination rates and narrow visible light response ranges. While BiOBr semiconductors possess relatively narrow band gaps, their small specific surface area and the ease with which photogenerated electron-hole pairs recombine limit the enhancement of catalytic activity. Therefore, there is an urgent need to develop novel, highly efficient composite photocatalysts to synergistically improve visible light capture and carrier separation capabilities, thereby achieving efficient removal of antibiotics and dye pollutants from water. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a GdCo-MOF / BiOBr composite material, its preparation method, and its application. A stable Z-shaped heterojunction is constructed between GdCo-MOF and BiOBr materials through Bi-O bond interactions, exhibiting significant photocatalytic performance. It can efficiently degrade various antibiotics and organic dyes under visible light, and its photocatalytic performance remains good even after multiple cycle experiments.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A GdCo-MOF / BiOBr composite material is proposed, comprising GdCo-MOF material and BiOBr nanosheets uniformly grown on its surface. The GdCo-MOF material uses pyridine-2,3-dicarboxylic acid as a ligand to bind with GdCo. 3+ Co 3+ The metal-organic framework material obtained by ion coordination has the chemical formula [GdCoL3(H2O)3]. n·9H2O, L 2- It is pyridine-2,3-dicarboxylic acid.
[0007] Preferably, the aforementioned BiOBr nanosheets account for less than 75% of the mass percentage in the GdCo-MOF / BiOBr composite material.
[0008] Preferably, the aforementioned GdCo-MOF material has a two-dimensional layered structure formed by gadolinium ions, cobalt ions and pyridine-2,3-dicarboxylic acid, and the layers are connected by hydrogen bonds to form a three-dimensional honeycomb pore structure.
[0009] The preparation method of GdCo-MOF / BiOBr composite material includes the following steps:
[0010] S1. Add gadolinium nitrate hexahydrate, cobalt acetate tetrahydrate and pyridine-2,3-dicarboxylic acid to a mixed solvent of water and organic solvent, and heat to react to obtain GdCo-MOF material;
[0011] S2. Dissolve sodium bromide in water, add GdCo-MOF material, and disperse by ultrasonication to obtain a mixture;
[0012] S3. Add an acetic acid solution of bismuth nitrate pentahydrate to the mixture, stir and react to obtain the GdCo-MOF / BiOBr composite material.
[0013] Preferably, in step S1, the molar ratio of gadolinium nitrate hexahydrate, cobalt acetate tetrahydrate, and pyridine-2,3-dicarboxylic acid is 1:1:(2-3), the heating temperature is 130-150℃, and the reaction time is 3-4h.
[0014] Preferably, in step S1, the volume ratio of water to organic solvent is (1.5-2):1, and the organic solvent is one or more of N,N-dimethylacetamide, ethylene glycol, and propylene glycol.
[0015] Preferably, the mass ratio of GdCo-MOF material, sodium bromide and bismuth nitrate pentahydrate is 1:(0.2-0.85):(0.9-4); the stirring reaction time is 2-4 hours.
[0016] Application of GdCo-MOF / BiOBr composite material in photocatalytic degradation of antibiotics in water, wherein the antibiotics are one or more of norfloxacin, levofloxacin, tetracycline or ciprofloxacin.
[0017] The application of GdCo-MOF / BiOBr composite material in the photocatalytic degradation of dyes in water is characterized by the dye being methylene blue or rhodamine B.
[0018] The advantages of this invention are as follows: This invention selects pyridine-2,3-dicarboxylic acid as a ligand to react with gadolinium ions and cobalt ions to synthesize a rare earth bimetallic GdCo-MOF that can effectively utilize visible light. By utilizing the Lewis acid-base interaction between the uncoordinated oxygen atoms in GdCo-MOF and bismuth ions in BiOBr, a stable GdCo-MOF / BiOBr-x Z-type heterojunction composite material is constructed. It can efficiently degrade antibiotics and dyes in water under visible light and has good structural stability. After multiple photocatalytic degradation cycle experiments, the photocatalytic performance remains good. Attached Figure Description
[0019] Figure 1 These are the X-ray diffraction patterns of the GdCo-MOF, GdCo-MOF / BiOBr-38, GdCo-MOF / BiOBr-55, GdCo-MOF / BiOBr-71 and BiOBr materials prepared in Examples 1 to 4;
[0020] Figure 2 These are scanning electron microscope images and elemental mapping diagrams of the GdCo-MOF material, GdCo-MOF / BiOBr-55 material and BiOBr material prepared in Examples 1 and 3 (a, GdCo-MOF material, b, BiOBr material, ce, GdCo-MOF / BiOBr-55 material);
[0021] Figure 3 These are the infrared spectra of the GdCo-MOF, GdCo-MOF / BiOBr-55, and BiOBr materials prepared in Examples 1 and 3;
[0022] Figure 4 These are the O1s orbital spectra of the GdCo-MOF, GdCo-MOF / BiOBr-55 and BiOBr materials prepared in Examples 1 and 3.
[0023] Figure 5 These are performance graphs of the photocatalytic degradation of norfloxacin by the GdCo-MOF, GdCo-MOF / BiOBr-38, GdCo-MOF / BiOBr-55, GdCo-MOF / BiOBr-71 and BiOBr materials prepared in Examples 1-4.
[0024] Figure 6 This is a graph showing the efficiency of the GdCo-MOF / BiOBr-55 material prepared in Example 3 in degrading various antibiotics and dyes;
[0025] Figure 7 This is a cyclic stability test diagram of the GdCo-MOF / BiOBr-55 material prepared in Example 3. Detailed implementation manners
[0026] The present invention will be specifically introduced below in conjunction with the accompanying drawings and specific embodiments.
[0027] Example 1
[0028] The preparation of the GdCo-MOF material includes the following steps:
[0029] 0.0903 g of gadolinium nitrate hexahydrate, 0.0498 g of cobalt acetate tetrahydrate and 0.1003 g of pyridine-2,3-dicarboxylic acid are added to a mixed solvent composed of 6 mL of water and 3 mL of N,N-dimethylacetamide, and heated under reflux with stirring in an oil bath at 140 °C for 4 h. After the reaction is completed, the pink precipitate is centrifuged, washed with water and anhydrous ethanol, and dried to obtain GdCo-MOF / BiOBr-x, where x is the mass ratio of BiOBr in the composite material, 0 < x < 75, and the sample with x taking the value of 0, that is, the GdCo-MOF material.
[0030] Example 2
[0031] The preparation of the GdCo-MOF / BiOBr-38 composite material includes the following steps:
[0032] After 0.0206 g of sodium bromide is dissolved in 10 mL of water, 0.1000 g of the GdCo-MOF material is added and ultrasonicated to disperse it evenly. Then 0.0970 g of bismuth nitrate pentahydrate is dissolved in 1 mL of acetic acid, and it is slowly added dropwise to the above-mentioned mixed solution under magnetic stirring, and stirring is continued for 3 h. After the reaction is completed, the GdCo-MOF / BiOBr-38 composite material is obtained through centrifugation, washing and drying.
[0033] Example 3
[0034] The preparation steps of this example are the same as those of Example 2, and the specific difference lies in the different dosages of each raw material: 0.0412 g of sodium bromide, 0.1940 g of bismuth nitrate pentahydrate, 2 mL of acetic acid, to obtain the GdCo-MOF / BiOBr-55 composite material.
[0035] Example 4
[0036] The preparation steps of this example are the same as those of Example 2, and the specific difference lies in the different dosages of each raw material: 0.0824 g of sodium bromide, 0.3881 g of bismuth nitrate pentahydrate, 4 mL of acetic acid, to obtain the GdCo-MOF / BiOBr-71 composite material.
[0037] Analysis of material structure and performance detection test
[0038] (1) Figure 1The X-ray diffraction patterns are those of the GdCo-MOF, GdCo-MOF / BiOBr-38, GdCo-MOF / BiOBr-55, GdCo-MOF / BiOBr-71 and BiOBr materials prepared in Examples 1 to 4.
[0039] from Figure 1 As can be seen, the characteristic peaks of GdCo-MOF and BiOBr coexist in the GdCo-MOF / BiOBr-x composite material. Furthermore, as the BiOBr content increases, the peak intensity of GdCo-MOF gradually decreases, which is due to the growth of BiOBr on the surface of GdCo-MOF, indicating that the composite material was successfully synthesized.
[0040] (2) Figure 2 Scanning electron microscope images and elemental mapping diagrams of the GdCo-MOF material prepared in Example 1, the GdCo-MOF / BiOBr-55 material prepared in Example 3, and the BiOBr material are shown.
[0041] from Figure 2 As can be seen, the GdCo-MOF material exhibits a smooth rod-like morphology, while the BiOBr material displays a spherical structure composed of aggregated two-dimensional nanosheets. After forming the GdCo-MOF / BiOBr-55 composite material, BiOBr grows uniformly on the MOF surface in the form of nanosheets. The corresponding EDS elemental mapping shows the uniform distribution of Gd, Co, N, O, Bi, and Br in the GdCo-MOF / BiOBr-55 composite material, confirming the successful construction of the GdCo-MOF / BiOBr-x composite material.
[0042] (3) Figure 3 and Figure 4 The images show the infrared spectra and X-ray photoelectron spectroscopy (O1s orbital spectra) of the GdCo-MOF material, GdCo-MOF / BiOBr-55 material, and BiOBr material prepared in Examples 1 and 3, respectively.
[0043] from Figure 3 It can be seen that the symmetric stretching vibration peak (1670 cm⁻¹) belonging to the carbonyl group (C=O) in the GdCo-MOF material is present. -1 ) and the peak belonging to the Bi-O bond in the BiOBr material (509 cm⁻¹) -1 Significant displacement occurred after the formation of the GdCo-MOF / BiOBr-55 composite material. The same phenomenon was observed from... Figure 4It can also be observed that, compared with individual GdCo-MOF and BiOBr materials, the peaks of Bi-O bonds (529.71 eV) in the GdCo-MOF / BiOBr-55 composite material and the peak of C=O (532.65 eV) in GdCo-MOF have shifted to varying degrees. These results indicate that there is a significant interfacial interaction between GdCo-MOF and BiOBr materials, with unbonded carboxyl oxygen atoms in GdCo-MOF interacting with BiO atoms in BiOBr. 3+ A heterojunction composite material was constructed by forming Bi-O bonds between them.
[0044] (4) Photocatalytic degradation performance test
[0045] The GdCo-MOF, GdCo-MOF / BiOBr-38, GdCo-MOF / BiOBr-55, and GdCo-MOF / BiOBr-71 materials prepared in Examples 1-4 were used as photocatalysts to conduct experiments on the visible light catalytic degradation of norfloxacin using a xenon lamp to simulate a visible light source. The steps were as follows: 50 mL of a 20 mg / L norfloxacin solution was added to a jacketed beaker as a simulated pollutant, along with 30 mg of the materials prepared in Examples 1-4. The mixture was stirred in the dark for 30 minutes to allow the catalyst to reach adsorption equilibrium with the norfloxacin solution. After the dark reaction, the xenon lamp was turned on to perform the photocatalytic degradation reaction of the norfloxacin solution. At selected time points, 1.5 mL of the suspension was collected, centrifuged, and the absorbance of the supernatant was measured using a UV-Vis spectrophotometer to calculate the concentration of norfloxacin. Specific results are shown in Table 1 and [Table data missing]. Figure 5 .
[0046] Table 1. Degradation efficiency of norfloxacin by the materials prepared in Examples 1-4 as photocatalysts.
[0047]
[0048]
[0049] According to Table 1 and Figure 5 It can be seen that among all catalysts, the GdCo-MOF / BiOBr-55 material prepared in Example 3 has the highest photocatalytic degradation rate of norfloxacin, with a degradation efficiency of 94.72% within 60 min.
[0050] (5) Photocatalysis universality test
[0051] As a preferred option, the GdCo-MOF / BiOBr-55 material prepared in Example 3 was used as the photocatalyst, and other antibiotics and dyes, such as methylene blue (MB), levofloxacin (LVF), tetracycline (TC), rhodamine B (RhB), and ciprofloxacin (CIP), were selected as simulated pollutants for photocatalytic degradation experiments.
[0052] Solutions of methylene blue, levofloxacin, tetracycline, rhodamine B, and ciprofloxacin were added to a jacketed beaker, respectively. The GdCo-MOF / BiOBr-55 material prepared in Example 3 was then added. The mixture was stirred in the dark for 30 minutes to allow the catalyst to reach adsorption equilibrium with the norfloxacin solution. After the dark reaction, a xenon lamp was turned on to perform a photocatalytic degradation reaction on the simulated pollutant solution. At selected time points, 1.5 mL of the suspension was collected, centrifuged, and the absorbance of the supernatant was measured using a UV-Vis spectrophotometer to calculate the concentration of the simulated pollutants. Specific results are shown in [link to results]. Figure 6 .
[0053] from Figure 6 As can be seen, the GdCo-MOF / BiOBr-55 material prepared in Example 3 exhibits degradation efficiencies of 98.55%, 88.22%, 84.71%, 98.67%, and 82.81% for methylene blue, levofloxacin, tetracycline, rhodamine B, and ciprofloxacin, respectively. This demonstrates that the GdCo-MOF / BiOBr-55 material exhibits good photocatalytic degradation performance for various antibiotics and dyes, demonstrating good photocatalytic versatility.
[0054] (6) Photocatalytic recyclability test
[0055] To investigate the recyclability of the material, the GdCo-MOF / BiOBr-55 material prepared in Example 3 was used as a photocatalyst to conduct four cycles of photocatalytic degradation experiments on norfloxacin. Specific results are shown in Table 2 and... Figure 7 .
[0056] Table 2. Cyclic degradation efficiency of norfloxacin by the GdCo-MOF / BiOBr-55 material prepared in Example 3.
[0057] Loop count Degradation efficiency (%) 1 94.72 2 91.83 3 87.47 4 85.67
[0058] like Figure 7 As shown in Table 2, it can be seen that after four cycles of the GdCo-MOF / BiOBr-55 material, the degradation efficiency of norfloxacin did not decrease significantly, indicating that it has good stability and can be recycled.
[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.
Claims
1. A GdCo-MOF / BiOBr composite material, characterized in that, The GdCo-MOF / BiOBr composite material comprises GdCo-MOF material and BiOBr nanosheets uniformly grown on its surface. The GdCo-MOF material uses pyridine-2,3-dicarboxylic acid as a ligand to bind with GdCo-MOF. 3+ Co 3+ The metal-organic framework material obtained by ion coordination has the chemical formula [GdCoL3(H2O)3]. n ·9H2O, L 2- It is pyridine-2,3-dicarboxylic acid.
2. The GdCo-MOF / BiOBr composite material according to claim 1, characterized in that, The BiOBr nanosheets constitute less than 75% of the mass percentage in the GdCo-MOF / BiOBr composite material.
3. The GdCo-MOF / BiOBr composite material according to claim 1, characterized in that, The GdCo-MOF and BiOBr form a Z-type heterojunction through the interfacial interaction of Bi-O bonds.
4. The GdCo-MOF / BiOBr composite material according to claim 1, characterized in that, The GdCo-MOF material has a two-dimensional layered structure formed by gadolinium ions, cobalt ions and pyridine-2,3-dicarboxylic acid, and the layers are connected by hydrogen bonds to form a three-dimensional honeycomb pore structure.
5. The method for preparing the GdCo-MOF / BiOBr composite material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Add gadolinium nitrate hexahydrate, cobalt acetate tetrahydrate and pyridine-2,3-dicarboxylic acid to a mixed solvent of water and organic solvent, and heat to react to obtain GdCo-MOF material; S2. Dissolve sodium bromide in water, add GdCo-MOF material, and disperse by ultrasonication to obtain a mixture; S3. Add an acetic acid solution of bismuth nitrate pentahydrate to the mixture, stir and react to obtain the GdCo-MOF / BiOBr composite material.
6. The preparation method according to claim 5, characterized in that, In step S1, the molar ratio of gadolinium nitrate hexahydrate, cobalt acetate tetrahydrate, and pyridine-2,3-dicarboxylic acid is 1:1:(2-3), the heating temperature is 130-150℃, and the reaction time is 3-4h.
7. The preparation method according to claim 5, characterized in that, In step S1, the volume ratio of water to organic solvent is (1.5-2):1, and the organic solvent is one or more of N,N-dimethylacetamide, ethylene glycol, and propylene glycol.
8. The preparation method according to claim 5, characterized in that, The mass ratio of GdCo-MOF material, sodium bromide and bismuth nitrate pentahydrate is 1:(0.2-0.85):(0.9-4); the stirring reaction time is 2-4 h.
9. The application of the GdCo-MOF / BiOBr composite material according to claim 1 in the photocatalytic degradation of antibiotics in water, characterized in that, The antibiotic is one or more of norfloxacin, levofloxacin, tetracycline, or ciprofloxacin.
10. The application of the GdCo-MOF / BiOBr composite material according to claim 1 in the photocatalytic degradation of dyes in water, characterized in that, The dye is methylene blue or rhodamine B.