MOF-74 derived bimetallic oxide material, preparation method and application in ultrafast sterilization and dye degradation

Abstract

The invention provides an MOF-74 derived bimetallic oxide material, a preparation method and application thereof in ultrafast sterilization and dye degradation, and belongs to the cross technical field of material science, electrochemical catalysis and water treatment environment protection. The bimetallic oxide material is an MgO / CuO bimetallic oxide material which is prepared by taking Mg / Cu-MOF-74 as a template through a pyrolysis method. The preparation method comprises the following steps: mixing and dissolving MgCl2. 6H2O, Cu (NO3) 2.3 H2O and 2, 5-dihydroxy terephthalic acid in a mixed solution of N, N-dimethylformamide, ethanol and water, reacting, cooling a reaction system after the reaction is finished, then centrifuging, washing and soaking a product, and finally standing to obtain Mg / Cu-MOF-74; and calcining Mg / Cu-MOF-74 at a high temperature to obtain the MgO / CuO bimetallic oxide material. The MgO / CuO bimetallic oxide material prepared by the invention has relatively high hydrogen peroxide selectivity and yield, can be used for killing pseudomonas aeruginosa in situ, has a relatively good sterilization effect, and can be used for rapidly degrading methylene blue dye in wastewater through electro-catalysis and Fenton reaction, so that the degradation efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary fields of materials science, electrochemical catalysis and water treatment and environmental protection, and particularly relates to a MOF-74 derived bimetallic oxide material, its preparation method and its application in ultrafast sterilization and dye degradation. Background Technology

[0002] The widespread transmission of pathogenic microorganisms such as bacteria and viruses seriously threatens human life and health. Simultaneously, with the rapid development of industries such as textiles, cosmetics, food, and pharmaceuticals, the problem of dye wastewater pollution has become increasingly prominent. This type of wastewater contains dyes that are highly toxic, carcinogenic, and mutagenic, posing a significant threat to natural ecosystems and human health. Therefore, developing efficient, safe, economical, and environmentally friendly sterilization and dye degradation technologies has become a crucial and urgent challenge in the field of environmental engineering. Existing sterilization processes, such as ultraviolet (UV) irradiation, chlorination, ozonation, and pulsed electric field treatment, inevitably suffer from drawbacks such as the generation of carcinogenic disinfection byproducts and excessive energy consumption. Existing dye degradation methods include physical and chemical methods. Physical methods (such as ultrasound, adsorption, and membrane filtration) can only achieve dye transfer, but are essentially adsorption and do not truly degrade the dye. While chemical methods have higher treatment efficiency, they generally suffer from high costs and the potential for secondary pollution such as toxic sludge and halogenated byproducts. Photodegradation is a research hotspot in dye degradation, but most synthetic dyes possess high chemical stability, resistance to photolysis, and resistance to biodegradation, making them persistent pollutants in the environment. While advanced oxidation techniques (AOPs) can completely mineralize dye molecules by generating strong oxidizing free radicals (such as ·OH), this technology requires expensive catalysts and oxidants, hindering its large-scale application.

[0003] Hydrogen peroxide (H2O2), as a green and environmentally friendly oxidant and energy carrier, produces only water and oxygen as reaction products, with no secondary pollution. It has been widely used in wound disinfection and water treatment, and its application in in-situ sterilization and synergistic Fenton reaction degradation of dyes shows significant advantages, making it an important direction for next-generation green disinfection and dye degradation technologies. However, the current mainstream industrial production method for H2O2 is the anthraquinone process. This method suffers from drawbacks such as large-scale infrastructure, complex operation, and the generation of large amounts of hazardous waste. Furthermore, H2O2 is easily decomposed and highly corrosive, leading to high storage and transportation costs and significant safety risks, severely limiting its widespread application in on-site disinfection and dye degradation scenarios.

[0004] To solve the above problems, O2 is used as a raw material through an electrochemical two-electron redox reaction (2e... -The technology of in-situ H2O2 generation (ORR) has emerged, offering mild reaction conditions, simple operation, and environmental friendliness. It allows for the direct on-site preparation of H2O2 for in-situ sterilization or synergistic Fenton degradation of dyes, eliminating the need for additional storage and transportation. It is considered an ideal alternative to the anthraquinone method. (2e) - The key to the success of ORR technology lies in designing and synthesizing highly efficient electrocatalysts. These catalysts must selectively reduce O2 to H2O2, rather than through a competitive four-electron redox pathway (4e...). - ORR) generates H2O. Currently, it is used for 2e - The catalyst materials for ORR mainly include noble metals and their alloys, carbon materials, single-atom catalysts, transition metal compounds, and metal-organic frameworks (MOFs). Among them, noble metal catalysts, although exhibiting excellent performance, high selectivity, and low overpotential, are hindered by scarcity and high cost, preventing large-scale application. Carbon-based materials are abundant and low-cost, with their activity stemming from defect engineering and heteroatom doping, but achieving specific structural designs with atomic precision is difficult. The active sites of transition metal compounds are easy to identify and control, but their tendency to aggregate leads to small specific surface area and poor porosity, limiting the utilization of internal active sites. The isolated sites of single-atom catalysts can significantly improve atomic utilization and 2e2e2. - ORR selectivity is achieved, but most single-atom catalysts have extremely low active phase content, resulting in unsatisfactory H2O2 yield.

[0005] Metal-organic frameworks (MOFs), as a class of porous materials assembled from metal ions and organic ligands, possess unique advantages such as large specific surface area, regular and controllable pore structure, and diverse chemical composition and functions. Their internally uniformly distributed and precisely defined metal centers are separated by ligands, essentially making them single-atom catalysts with high content of isolated active centers. The reaction environment and electronic structure of the active centers can be customized by controlling the type of ligands or metal nodes. High porosity also promotes the exposure of active sites and mass transfer processes, and they are easily hybridized with other functional materials to form multifunctional composite materials. - The ORR catalysis field shows great potential. However, rudimentary MOF materials suffer from inherent defects such as low conductivity and poor electrochemical stability, making their electrocatalytic performance insufficient for practical applications and greatly limiting their industrial application as electrochemical catalysts. Research has found that MOF materials can be used as sacrificial templates and transformed into MOF derivatives such as porous carbon, metal compounds, and their composites through pyrolysis and oxidation. Compared with rudimentary MOFs and MOF composites, MOF derivatives typically exhibit significantly improved conductivity and stability, effectively overcoming the performance shortcomings of rudimentary MOFs. Therefore, MOF derivatives have become a highly promising 2e-phase catalyst. - The electrocatalyst for preparing H2O2 by ORR has significant research and application value in the in-situ electrocatalytic generation of H2O2 for ultrafast sterilization and synergistic Fenton reaction degradation of dyes. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a MOF-74-derived bimetallic oxide material, its preparation method, and its application in ultrafast sterilization and dye degradation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of the present invention: This invention provides a MOF-74-derived bimetallic oxide material, wherein the bimetallic oxide material is a MgO / CuO bimetallic oxide material prepared by pyrolysis using Mg / Cu-MOF-74 as a template.

[0008] The second technical solution of the present invention: A method for preparing the MOF-74-derived bimetallic oxide material includes the following steps: (1) MgCl2·6H2O, Cu(NO3)2·3H2O and 2,5-dihydroxyterephthalic acid were mixed and dissolved in a mixed solution of N,N-dimethylformamide, ethanol and water, and the reaction was carried out. After the reaction was completed, the reaction system was cooled, and the reaction product was centrifuged, washed and soaked. Finally, after standing, the Mg / Cu-MOF-74 was obtained. (2) The Mg / Cu-MOF-74 is heated and kept at a constant temperature, and then cooled to obtain the MgO / CuO bimetallic oxide material.

[0009] Further, in step (1), the ratio of MgCl2·6H2O, Cu(NO3)2·3H2O and 2,5-dihydroxyterephthalic acid is 1.7∶2.0∶1.0; The volume ratio of N,N-dimethylformamide, ethanol, and water is 1.5:1:1; The mass ratio of 2,5-dihydroxyterephthalic acid to N,N-dimethylformamide is 1:(182-183).

[0010] Furthermore, the reaction in step (1) is carried out at a temperature of 120–160 °C for 16–24 h.

[0011] Furthermore, the centrifugation speed in step (1) is 7000-8000 rpm, and the time is 5-10 min; The washing process involves washing the centrifuged solid with N,N-dimethylformamide 3 to 5 times. The soaking process involves immersing the washed product in methanol for 3 days, with the methanol being replaced every 12 hours. The settling process involves standing in a vacuum at 60 °C for 12 h to remove methanol solvent. The cooling process involves natural cooling to room temperature.

[0012] Further, the heating and heat preservation in step (2) is to raise the temperature to 800 ℃ at a heating rate of 5 ℃ / min, and then keep it at 800 ℃ in an argon atmosphere for 1 h; The cooling process involves natural cooling to room temperature.

[0013] The third technical solution of the present invention: A method for preparing hydrogen peroxide involves using a bimetallic oxide material derived from MOF-74 to perform an electrocatalytic redox reaction to obtain the hydrogen peroxide.

[0014] The fourth technical solution of the present invention: A method for sterilizing Pseudomonas aeruginosa involves using the MOF-74-derived bimetallic oxide material as a catalyst to perform an electrocatalytic redox reaction to generate hydrogen peroxide, which then acts in situ on Pseudomonas aeruginosa for sterilization.

[0015] Furthermore, the MOF-74-derived bimetallic oxide material achieves a sterilization efficiency of 99.99% after 5 minutes of electrocatalysis and complete sterilization after 10 minutes, realizing ultra-fast sterilization.

[0016] The fifth technical solution of the present invention: A method for rapidly degrading dyes in water is characterized by using the MOF-74-derived bimetallic oxide material as a catalyst to carry out an electrocatalytic redox reaction to generate hydrogen peroxide, and then adding ferrous ions to water to construct an electrocatalytic-Fenton reaction system to complete the degradation of dyes in water.

[0017] Furthermore, the dye is methylene blue dye; The degradation time is 5 to 30 minutes.

[0018] The beneficial effects of this invention compared to the prior art are as follows: This invention prepares a MgO / CuO bimetallic oxide material using Mg / Cu-MOF-74 as a template. This material acts as a catalyst for the electrocatalytic redox production of hydrogen peroxide. The MgO / CuO bimetallic oxide material exhibits high selectivity and yield for hydrogen peroxide, with a selectivity reaching 70%. The yield of hydrogen peroxide increases with time, reaching 600 mmol·g⁻¹. cat -1 ·h -1 ·L -1The generated hydrogen peroxide was used in situ to kill Pseudomonas aeruginosa, showing good bactericidal effect. The bactericidal efficiency reached 99.99% after 5 minutes, and all bacteria were killed after 10 minutes. This invention has broad application value and prospects in environmental pollution treatment, water treatment, and pharmaceutical sterilization.

[0019] This invention uses the prepared MgO / CuO bimetallic oxide material as a catalyst to electrocatalyze the oxidation-reduction to produce hydrogen peroxide. The generated hydrogen peroxide reacts with ferrous ions added to the solution to construct an electrocatalytic-Fenton reaction (Fe2O3- ... 2+ The invention utilizes a (-H2O2) system to rapidly degrade dyes via electrocatalysis and a synergistic Fenton reaction, achieving complete degradation of methylene blue dye in just 10 minutes. This invention achieves rapid, green, and efficient degradation of organic pollutants, demonstrating broad application value and prospects in environmental protection, water treatment, and pollutant degradation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The images shown are scanning electron microscope (SEM) images of the MgO / CuO bimetallic oxide material prepared in Example 1 of the present invention. Figure a is an overall morphology image, and Figure b is an elemental distribution image of Mg, Cu, and O. Figure 2 The images show SEM images of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. Specifically, Figure a is a SEM image of MOF-74 (Mg), Figure b is a SEM image of MOF-74 (Mg / Cu), Figure c is a SEM image of MOF-74 (Cu), Figure d is a SEM image of the MgO oxide material, Figure e is a SEM image of the MgO / CuO bimetallic oxide material, and Figure f is a SEM image of the CuO oxide material. Figure 3The XRD patterns of the precursor MOF-74 (Mg / Cu) and product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and product CuO oxide material prepared in Comparative Example 2 are shown in Figure 1. Figure a shows the XRD pattern of the precursor prepared in Example 1 and Comparative Examples 1-2, and Figure b shows the XRD pattern of the product prepared in Example 1 and Comparative Examples 1-2. Figure 4 The images show the XPS diagrams of the crystal structures of the precursor MOF-74 (Mg / Cu) prepared in Example 1, the precursor MOF-74 (Mg) prepared in Comparative Example 1, and the precursor MOF-74 (Cu) prepared in Comparative Example 2. In Figure a, the Mg 1s spectrum is shown and the Cu 2p spectrum is shown. Figure 5 The figures show the XPS images of the crystal structures of the MgO / CuO bimetallic oxide material prepared in Example 1, the MgO oxide material prepared in Comparative Example 1, and the CuO oxide material prepared in Comparative Example 2, wherein Figure a is the Mg 1s spectrum and Figure b is the Cu 2p fine spectrum. Figure 6 The figures show the cyclic voltammetry curves of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. Figure a shows the cyclic voltammetry curves of the precursors prepared in Example 1 and Comparative Examples 1-2, and Figure b shows the cyclic voltammetry curves of the products prepared in Example 1 and Comparative Examples 1-2. The dashed lines in the figures represent the curves under saturated N2, and the solid lines represent the curves under saturated O2. Figure 7 The figures show polarization curves of the precursor MOF-74 (Mg / Cu) and product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and product CuO oxide material prepared in Comparative Example 2. Figure a shows the polarization curves of the precursors prepared in Example 1 and Comparative Examples 1-2, and Figure b shows the polarization curves of the products prepared in Example 1 and Comparative Examples 1-2. In the figures, the dashed line represents the current curve detected by the pt ring electrode, and the solid line represents the current curve detected on the disk. Figure 8Figure 1 shows the overpotential histograms of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1 of the present invention, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. Figure 2a shows the overpotential histograms of the precursors prepared in Example 1 and Comparative Examples 1-2, and Figure 2b shows the overpotential histograms of the products prepared in Example 1 and Comparative Examples 1-2. Figure 9 The graphs show the selectivity of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2 to H2O2. In particular, Figure a shows the selectivity of the precursors prepared in Example 1 and Comparative Examples 1-2 to H2O2, and Figure b shows the selectivity of the products prepared in Example 1 and Comparative Examples 1-2 to H2O2. Figure 10 The graphs show the electron transfer numbers of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. In particular, Figure a is a graph showing the electron transfer numbers of the precursors prepared in Example 1 and Comparative Examples 1-2, and Figure b is a graph showing the electron transfer numbers of the products prepared in Example 1 and Comparative Examples 1-2. Figure 11 The figures are Tafel curves of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1 of the present invention, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. Figure a is the Tafel curve of the precursor prepared in Example 1 and Comparative Examples 1-2, and Figure b is the Tafel curve of the product prepared in Example 1 and Comparative Examples 1-2. Figure 12Figure 1 shows the CV curves of the precursor MOF-74 (Mg / Cu) and the product MgO / CuO bimetallic oxide material prepared in Example 1 of this invention, the precursor MOF-74 (Mg) and the product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and the product CuO oxide material prepared in Comparative Example 2. Figure 2 shows the CV curves of MOF-74 (Mg), MOF-74 (Mg / Cu), MOF-74 (Cu), MgO oxide material, MgO / CuO bimetallic oxide material, CuO oxide material, and ECSA curves of the precursors and products prepared in Example 1 and Comparative Examples 1-2. Figure 13 Figure 1 shows the stability curves of the MgO / CuO bimetallic oxide material prepared in Example 1 of this invention in a 3.5% NaCl solution saturated with O2. Figure 1a shows the LSV curve of the MgO / CuO bimetallic oxide material before and after the stability test, Figure 2b shows the selectivity curve of the MgO / CuO bimetallic oxide material before and after the stability test, and Figure 2c shows the electron transfer number curve of the MgO / CuO bimetallic oxide material before and after the stability test. Figure 14 Figure 1 shows the electrocatalytic redox reaction performance of the MgO / CuO bimetallic oxide material prepared in Example 1 of this invention. Figure 1a is the LSV curve, Figure 2b is the H2O2 selectivity curve in the electrocatalytic reaction, and Figure 2c is the H2O2 yield curve. Figure 15 The figures show the H2O2 yield curves of the precursor MOF-74 (Mg / Cu) and product MgO / CuO bimetallic oxide material prepared in Example 1, the precursor MOF-74 (Mg) and product MgO oxide material prepared in Comparative Example 1, and the precursor MOF-74 (Cu) and product CuO oxide material prepared in Comparative Example 2. Figure a shows the H2O2 yield curve of the precursors prepared in Example 1 and Comparative Examples 1-2; Figure b shows the H2O2 selectivity curve of the precursors prepared in Example 1 and Comparative Examples 1-2; Figure c shows the H2O2 yield curve of the product prepared in Example 1 and Comparative Examples 1-2; and Figure d shows the H2O2 selectivity curve of the product prepared in Example 1 and Comparative Examples 1-2. Figure 16 Figure 1 shows the electrocatalytic sterilization of the MgO / CuO bimetallic oxide material prepared in Example 1 of the present invention. Figure 1a is a picture of the actual product after sampling and plating on plates for different electrocatalytic reaction times. Figure 2b is a sterilization efficiency curve. Figure 17The graph shows the electrocatalytic synergistic effect of the MgO / CuO bimetallic oxide material prepared in Example 1 of this invention on the degradation of methylene blue dye by Fenton. Detailed Implementation

[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0023] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0025] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0026] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0027] All raw materials used in the following embodiments of the present invention can be purchased commercially.

[0028] In the following embodiments of the present invention, the room temperature refers to 23±2 ℃.

[0029] In the following embodiments of the present invention, the water is preferably deionized water.

[0030] Example 1 A method for preparing a MOF-74-derived bimetallic oxide material includes the following steps: (1) 0.2635 g MgCl2·6H2O, 0.31 g Cu(NO3)2·3H2O and 0.155 g 2,5-dihydroxyterephthalic acid were mixed and dissolved in 70 mL of a mixed solution of N,N-dimethylformamide, ethanol and deionized water, wherein the volume ratio of N,N-dimethylformamide, ethanol and deionized water was 1.5:1:1. The dissolved solution was then transferred to a stainless steel high-pressure reactor and reacted in an oven at 135 °C for 20 h. After the reaction was completed, the reactor was allowed to cool naturally to room temperature and centrifuged at 7000 rpm for 10 min to collect the reaction product. The reaction product was washed three times with N,N-dimethylformamide and then soaked in methanol for three days. Finally, it was allowed to stand in a vacuum at 60 °C for 12 h to remove the methanol solvent and obtain the activated light yellow porous material, namely the precursor Mg / Cu-MOF-74 (MOF-74(Mg / Cu)).

[0031] (2) The above Mg / Cu-MOF-74 was heated to 800 ℃ at a heating rate of 5 ℃ / min, kept at the temperature for 1 h in an argon atmosphere, and then naturally cooled to room temperature to obtain MgO / CuO bimetallic oxide material.

[0032] The MgO / CuO bimetallic oxide material prepared in Example 1 was subjected to electron microscopy scanning, and the scanning results are as follows: Figure 1 As shown, through Figure 1 As can be seen, the prepared MgO / CuO bimetallic oxide material has a petal-like morphology and a regular and ordered structure. Figure 1 The b-element distribution diagram clearly shows that MgO and CuO are evenly distributed, indicating that the bimetallic oxide was successfully prepared.

[0033] Comparative Example 1 A method for preparing an oxide material derived from MOF-74 differs from Example 1 in that: in step (1), Cu(NO3)2·3H2O is replaced with an equal amount of MgCl2·6H2O, that is, Cu(NO3)2·3H2O is not added, and all of it is added to MgCl2·6H2O. In step (1), the precursor Mg-MOF-74 (MOF-74(Mg)) is prepared. The selection and preparation methods of the remaining raw materials are the same as in Example 1, and MgO oxide materials are prepared.

[0034] Comparative Example 2 A method for preparing an oxide material derived from MOF-74 differs from Example 1 in that: in step (1), MgCl2·6H2O is replaced with an equal amount of Cu(NO3)2·3H2O, that is, MgCl2·6H2O is not added, and all Cu(NO3)2·3H2O is added. In step (1), the precursor Cu-MOF-74 (MOF-74(Cu)) is prepared. The selection and preparation methods of the remaining raw materials are the same as in Example 1, and CuO oxide materials are prepared.

[0035] 1. Characterization of the precursors and products prepared in Example 1 and Comparative Examples 1-2 The MOF-74 (Mg / Cu) prepared in Example 1, the MOF-74 (Mg) prepared in Comparative Example 1, and the MOF-74 (Cu) prepared in Comparative Example 2 were characterized by SEM, and the results are as follows: Figure 2 As shown in ac, through Figure 2 As can be seen, MOF-74(Mg) exhibits a petal-like morphology, with a crystal size of approximately 10 μm; through... Figure 2 b shows that when Cu ions are doped into MOF-74(Mg), the resulting MOF-74(Mg / Cu) morphology still exhibits a petal-like shape, but the crystal size is reduced to approximately 2 μm; through Figure 2 c shows that when MOF-74 contains only Cu ions, the morphology of MOF-74 undergoes a huge change, changing from a petal-like shape to an irregular blocky shape composed of needle-like crystals. This is because the crystal structure changes after Cu ions completely replace Mg ions.

[0036] The MOF-74 (Mg / Cu) prepared in Example 1, the MOF-74 (Mg) prepared in Comparative Example 1, and the MOF-74 (Cu) prepared in Comparative Example 2 were subjected to pyrolysis, and the results are as follows: Figure 2 As shown in df, through Figure 2 d and Figure 2 As can be seen, the morphology of both the obtained MgO / CuO bimetallic oxide material and the MgO oxide material did not change significantly, retaining the petal-like shape, but the petal size decreased. This is due to the decomposition of organic ligands during pyrolysis. This result indicates that the metal oxide obtained from the MOF-74 precursor through pyrolysis retains the porous structure of MOF-74. However, the morphology of the CuO oxide material was completely altered. Figure 2 f), the needle-like crystals in the MOF-74 precursor disappeared, turning into completely irregular blocks.

[0037] XRD analysis was performed on the crystal structures of the precursors and products prepared in Example 1 and Comparative Examples 1-2, and the results are as follows: Figure 3 As shown, through Figure 3As can be seen, the diffraction peaks of MOF-74(Mg) and MOF-74(Mg / Cu) are consistent with the simulated XRD of MOF-74(Mg), with a significant diffraction peak at 11.8°, corresponding to the (300) crystal plane. Furthermore, the XRD patterns show fewer impurity peaks, proving that MOF-74(Mg) and MOF-74(Mg / Cu) were successfully synthesized. While MOF-74(Cu) also produced a diffraction peak at 11.8°, the peak intensity was extremely low and contained many impurity peaks. Comparing these peaks with standard cards revealed that they corresponded to the Cu2O (JCPDS34-1354) standard card. This indicates that the MOF-74(Cu) sample is a mixture of MOF-74(Cu) and Cu2O, and the intensity of the diffraction peaks suggests a high Cu2O content. XRD analysis of the products obtained by pyrolysis of the precursors prepared in Example 1 and Comparative Examples 1-2 revealed that the crystalline phase of MOF-74 completely disappeared, while the crystalline phases of MgO and CuO appeared. Figure 3 As shown in b, the pyrolysis of organic ligands and the formation of MgO and CuO during the pyrolysis of MOF precursors are confirmed. Comparing the standard cards for MgO (JCPDS 45-0946) and CuO (JCPDS 48-1548), the diffraction peaks of MgO at 36.9°, 42.9°, 62.3°, 74.7°, and 78.6° correspond to the (111), (200), (220), (311), and (222) crystal planes, while the diffraction peaks of CuO at 32.5°, 35.5°, 38.7°, 48.7°, 53.4°, 58.3°, 61.5°, 65.8°, 67.9°, 72.4°, and 75.0° correspond to the (-110), (002), (111), (-202), (020), (202), (-113), (022), (113), (311), and (004) crystal planes, and no other impurity phases were observed. Figure 3 The XRD results show the successful preparation of MOF precursor-derived MgO, MgO / CuO, and CuO.

[0038] To further analyze the crystal structure and valence state information of the precursors and products prepared in Example 1 and Comparative Examples 1-2, XPS tests were performed. The XPS test results of the precursors are as follows: Figure 4 As shown, through Figure 4 As can be seen, the characteristic Mg 1s peak of MOF-74(Mg) and MOF-74(Mg / Cu) samples appears at 1304.8 eV, while MOF-74(Cu) does not show a characteristic peak in the Mg 1s fine spectrum. Figure 4As can be seen from b, MOF-74(Mg) also does not show characteristic peaks in the Cu 2p fine spectrum, while Cu appears at 934.88 eV in MOF-74(Mg / Cu). 2+ 2p 3 / 2 The characteristic peak of Cu appears at 954.88 eV. 2+ 2p 1 / 2 The characteristic peaks of Cu are present, and there are multiple satellite peaks, while MOF-74 (Cu) has only Cu at 934.88 eV. 2+ 2p 3 / 2 Characteristic peak, Cu at 954.88 eV 2+ 2p 1 / 2 In addition to the characteristic peak and multiple satellite peaks, Cu also appeared at 932.78 eV. + 2p 3 / 2 The characteristic peaks indicate the presence of Cu in MOF-74 (Cu). 2+ and Cu + The presence of two valence states of Cu further confirms that the MOF-74(Cu) sample is a mixture of MOF-74(Cu) and Cu2O.

[0039] XPS test results of the products prepared in Example 1 and Comparative Examples 1-2 are as follows: Figure 5 As shown, through Figure 5 As can be seen from the Mg 1s XPS spectrum, MgO exhibits a characteristic Mg 1s peak at 1304 eV, while the Mg 1s characteristic peak of MgO / CuO appears at 1304.2 eV, showing a shift. This is because the recombination of MgO and CuO adjusts the electronic structure of MgO, causing its peak to shift. Similarly, CuO does not show a characteristic peak in the Mg 1s XPS spectrum. Figure 5 As can be seen from b, in the Cu 2p XPS spectrum, the spectra of MgO and MgO / CuO are similar to those of their MOF precursors. MgO still lacks characteristic peaks, while CuO / CuO exhibits... 2+ 2p 3 / 2 The binding energy peak appears at 934.88 eV, Cu 2+ 2p 1 / 2 The binding energy peak appears at 954.88 eV and has multiple satellite peaks. In contrast, CuO, compared to MOF-74 (Cu), only has a peak at 934.88 eV. 2+ 2p 3 / 2 Characteristic peak, Cu at 954.88 eV 2+ 2p 1 / 2 Characteristic peaks and multiple satellite peaks, Cu at 932.78 eV + 2p 3 / 2 The characteristic peaks disappeared because of Cu in Cu₂O.+ It was oxidized to Cu during the pyrolysis process. 2+ This leads to Cu + The disappearance of MgO, MgO / CuO, and CuO further proves the successful preparation of these compounds.

[0040] 2. Electrocatalytic redox performance testing of the precursors and products prepared in Example 1 and Comparative Examples 1-2 Electrocatalytic 2e of the precursors and products prepared in Example 1 and Comparative Examples 1-2 - ORR performance was verified. This verification process was performed on a rotating ring-disc electrode apparatus. To preliminarily determine the ORR activity of the prepared catalyst, it was reacted in 3.5% NaCl solutions containing saturated N2 or O2 at a rate of 100 mV·s. -1 The scan rate was used to test the cyclic voltammetry (CV) curves of the precursors and products prepared in Example 1 and Comparative Examples 1-2. Figure 6 As shown, the metal oxides and their precursors exhibited obvious reduction peaks in 3.5% NaCl electrolyte containing saturated O2, while no obvious redox peaks were observed in 3.5% NaCl electrolyte saturated with N2. This indicates that the precursors and products prepared in Example 1 and Comparative Examples 1-2 have significant electrocatalytic activity for the ORR process.

[0041] To further determine the effect of the catalyst on 2e - The catalytic performance of ORR was assessed by polarization curves (LSV curves) of MgO, MgO / CuO, CuO, and their MOF precursors at 1600 rpm using RRDE testing. Figure 7 As shown, the linear LSV curve of the MOF precursor shows that the current density gradually decreases as the electrode potential gradually decreases towards the reduction potential, indicating that the MOF precursor has good ORR catalytic activity. The LSV curves of the metal oxides derived from the MOF precursor show the same trend. Compared with the MOF precursor and single metal oxides, MgO / CuO has a lower current density, indicating that MgO / CuO has higher ORR catalytic activity.

[0042] The LSV curves of MOF precursors and oxide materials were calculated at 0.1 mA cm⁻¹. -2 The overpotentials corresponding to MOF precursors and oxide materials, such as Figure 8 As shown, through Figure 8It can be seen that the smaller the overpotential of the MOF precursor and oxide material, the faster the ORR kinetics and the faster the electron transfer rate during the reaction. Compared with MOF precursors and single metal oxides, MgO / CuO has a smaller overpotential, indicating that MgO / CuO has better ORR catalytic performance. This is because MgO / CuO derived from MOF precursors has the porous structure of MOF, exposing more active sites. At the same time, MgO / CuO also has the excellent conductivity and stability of metal oxides, thus giving MgO / CuO better ORR catalytic performance.

[0043] Based on RRDE test data, the selectivity and electron transfer number of MOF precursors and oxide materials to H2O2 were calculated, and the selectivity was as follows: Figure 9 As shown, among the MOF precursors, the H2O2 selectivity of MOF-74(Mg) and MOF-74(Mg / Cu) is approximately 60%, with MOF-74(Mg / Cu) exhibiting slightly higher selectivity. In contrast, the H2O2 selectivity of MOF-74(Cu) is less than 40%. This indicates that the 2e- ... - The ORR active site originates from Mg, and the synergistic effect between Mg and Cu further enhances its selectivity after Cu doping. Furthermore, the pyrolysis of the MOF-74 (Mg / Cu) precursor resulted in MgO / CuO with even higher H2O2 selectivity, approaching 70%, indicating that the MgO / CuO catalyst is more conducive to the formation of 2e- electrons for H2O2. - The ORR pathway, instead of 4e - ORR pathway.

[0044] Electron transfer number such as Figure 10 As shown, through Figure 10 It can be clearly observed that the electron transfer numbers of MgO, MgO / CuO, and the MOF precursor are all between 2 and 3, indicating that the MOF precursors and oxide materials prepared in Example 1 and Comparative Examples 1-2 are more favorable for 2e electron transfer. - The ORR pathway. The electron transfer number in CuO is between 3 and 4, which favors 4e. - ORR pathway. The electron transfer number of the MgO / CuO bimetallic oxide material prepared in Example 1 is closer to 2, which further illustrates that the ORR of the MgO / CuO bimetallic oxide material is 2e - The primary pathway is [not specified]. Furthermore, Tafel curves were plotted based on the ORR polarization curves of the MOF precursors and oxide materials prepared in Example 1 and Comparative Examples 1-2, as shown below. Figure 11 As shown, through Figure 11 As shown, the Tafel slope of the MgO / CuO bimetallic oxide material prepared in Example 1 is 88 mV Dec.-1 Lower than MOF-74(Mg) (240 mV Dec) -1 ), MOF-74 (Mg / Cu) (217 mV Dec -1 ), MOF-74 (Cu) (132 mV Dec -1 ), MgO (258 mV Dec) -1 ) and CuO (260 mVDec -1 This indicates that the MgO / CuO bimetallic oxide material prepared in Example 1 has a rapid 2e... - ORR dynamics.

[0045] The ECSA (electrochemical active surface area) of the precursors and products prepared in Example 1 and Comparative Examples 1-2 was measured. ECSA is another important parameter for evaluating the activity of electrocatalysts; a higher ECSA usually indicates higher catalytic activity. ECSA is determined based on ECSA and C. dl It is calculated based on the direct proportional relationship between them, where C dl It was calculated based on the CV curves scanned at different speeds in a 3.5% NaCl solution, such as... Figure 12 As shown in af, in Figure 12 In g, compared with MOF precursors and single metal oxides, the MgO / CuO bimetallic oxide material prepared in Example 1 has the highest C content. dl The value indicates that the MgO / CuO bimetallic oxide material derived from MOF-74 (Mg / Cu) possesses the highest ECSA and better 2e. - The ORR catalytic performance results demonstrate that the MOF-74 (Mg / Cu)-derived MgO / CuO bimetallic oxide material retains the porous structure of MOF, allowing the MgO / CuO bimetallic oxide material to expose more 2e. - ORR active site. In addition, the C of MOF-74(Cu) dl Its specific surface area is only lower than that of MgO / CuO bimetallic oxide materials and MOF-74(Mg), while its H2O2 selectivity is the lowest. This indicates that MOF-74(Cu) has a larger specific surface area, but its exposed active sites are more conducive to the transmission of 4e. - H2O is generated via the ORR pathway.

[0046] The stability of the MgO / CuO bimetallic oxide material prepared in Example 1 in an O2-saturated 3.5% NaCl solution was studied by long-term stability measurement of 2000 CV cycles within a potential range close to the onset potential of the MgO / CuO bimetallic oxide material. Figure 13 As shown, in Figure 13In step a, compared to the initial polarization curve of the MgO / CuO bimetallic oxide material, the current density of the polarization curve after 2000 cycles decreased slightly. Simultaneously, the selectivity of the MgO / CuO bimetallic oxide material for H2O2 after 2000 cycles (e.g., ...) was calculated. Figure 13 (as shown in b) and electron transfer number (as shown in b) Figure 13 (as shown in c), through Figure 13 As can be seen from bc, after 2000 cycles, the selectivity of the MgO / CuO bimetallic oxide material is still close to 60%, and the electron transfer number is about 2.8, indicating that the MgO / CuO bimetallic oxide material still maintains a high 2e electron transfer rate after 2000 CV cycles. - The ORR catalytic activity confirmed that the MOF-74 (Mg / Cu)-derived MgO / CuO bimetallic oxide material has good stability.

[0047] Application Example 1 5 mg of the MgO / CuO bimetallic oxide material prepared in Example 1 was weighed and dispersed in 1 mL of isopropanol to prepare a catalyst solution. This catalyst solution was then added dropwise to a glassy carbon electrode as the working electrode. Using rotating disk ring electrode technology (RRDE) with a simulated seawater 0.5 M NaCl solution as the electrolyte, the disk current and ring current of the electrocatalytic redox reaction of the MgO / CuO bimetallic oxide material were tested at room temperature and a rotation speed of 1600 rpm. Hydrogen peroxide was produced in a 3.5% NaCl solution using an H-Cell electrolyzer. The amount of hydrogen peroxide generated was determined by conventional Ce(SO4)2 titration.

[0048] The electrocatalytic redox reaction performance of the MgO / CuO bimetallic oxide material prepared in Example 1 is shown in the figure below. Figure 14 As shown, in Figure 14 In diagram a, the disk current density represents the reduction current of the electrocatalytic redox reaction, and the ring current represents the reduction current for the electrocatalytic production of hydrogen peroxide. Figure 14 As can be seen, MgO / CuO can drive ORR in this system and exhibits a stable current response in the high potential region, indicating that the MgO / CuO bimetallic oxide material prepared in Example 1 possesses ORR catalytic ability. The selectivity of hydrogen peroxide during the electrocatalytic reaction can be obtained from the disk-ring current, such as... Figure 14 As shown in b, through Figure 14 As can be seen from b, the MgO / CuO bimetallic oxide material exhibits high hydrogen peroxide selectivity, reaching 70%. Figure 14 c shows that the yield of H2O2 increases with time, reaching 600 mmol·g. cat -1 ·h-1 ·L -1 .

[0049] The yields of hydrogen peroxide produced by the electrocatalytic oxidation-reduction of the precursors and products prepared in Examples 1 and 1-2 were tested. The precursors and products prepared in Examples 1 and 1-2 were used in the hydrogen peroxide production process, with H2O2 produced in a 3.5% NaCl solution using an H-Cell electrolyzer. The amount of H2O2 produced was detected by the conventional Ce(SO4)2 titration method, and the results are as follows. Figure 15 The figure shows the cumulative H2O2 content of various catalysts in a 3.5% NaCl solution containing saturated O2. From... Figure 15 a and Figure 15 As shown in Figure c, the yield of H2O2 increases with time. Comparing the H2O2 yields of MgO, MgO / CuO, CuO, and their MOF precursors at 1 h, the trend is consistent with the change in the H2O2 selectivity of the catalyst. The MgO / CuO bimetallic oxide material prepared in Example 1 still has the highest H2O2 yield, reaching 600 mmol·g. cat -1 ·h -1 ·L -1 Furthermore, the Faradaic efficiency of H2O2 is another important parameter for evaluating catalyst performance. The Faradaic efficiency was calculated based on the actual H2O2 content produced by the catalyst. Figure 15 (b and d). The results show that the Faradaic efficiencies of MgO, MgO / CuO, CuO and their MOF precursor catalysts range from 20% to 50%. Among them, the MgO / CuO bimetallic oxide catalyst prepared in Example 1 has the highest Faradaic efficiency, approximately 50%.

[0050] Application Example 2 The bactericidal performance of the MgO / CuO bimetallic oxide catalyst prepared in Example 1 in 3.5% NaCl solution was tested using an H-type electrolytic cell and Pseudomonas aeruginosa marine bacteria to simulate practical bactericidal applications. The concentration of Pseudomonas aeruginosa was approximately 10⁻⁶ by plate counting. 8 cfu·mL -1 The bacteria were diluted in the electrolyte under sterile conditions. During the IT measurement, electrolyte concentrations of different bacterial concentrations were collected at a series of time points: 0, 5, and 10 min. The collected electrolyte was further diluted and plated. After plating, the plates were incubated for 24 h. The agar plate images of the colonies are shown below. Figure 16 As shown in Figure a, with increasing electrocatalytic time, more hydrogen peroxide was produced, causing a gradual decrease in the number of colonies, which dropped to single digits after 5 minutes. The graph showing the changes in bacterial concentration and sterilization rate over time based on the test results is shown below. Figure 16 As shown in b, the results indicate that the MgO / CuO bimetallic oxide material prepared in Example 1 has a good disinfection effect on Pseudomonas aeruginosa, with a sterilization efficiency of 99.99% at 5 min and complete sterilization at 10 min.

[0051] Application Example 3 1 mg of the MgO / CuO bimetallic oxide material prepared in Example 1 was weighed and dispersed in 1 mL of isopropanol to prepare a catalyst solution. The uniformly dispersed solution was sprayed onto carbon paper (1 cm × 2 cm) as the working electrode. 50 mL of 0.5 M NaCl solution was used as the electrolyte solution, a saturated calomel electrode was used as the reference electrode, and a carbon rod was used as the counter electrode. 2 mM methylene blue dye was added to the electrolyte solution, and the solution was mixed. Then, 0.6 mM ferrous chloride was added to the mixed solution and stirred until homogeneous. Under oxygen-fluxed conditions, the dye was electrocatalyzed to produce hydrogen peroxide for degradation using a chronoamperometry method. During the degradation process, 1 mL of the degradation solution was taken at 5 min, 10 min, 20 min, and 30 min for UV-Vis spectroscopy, and the absorbance at 664 nm was plotted.

[0052] Application Comparative Example 1 Weigh 1 mg of the MgO / CuO bimetallic oxide material prepared in Example 1 and disperse it in 1 mL of isopropanol to prepare a catalyst solution. Spray the uniformly dispersed solution onto carbon paper (1 cm × 2 cm) as the working electrode. Use 50 mL of 0.5 M NaCl solution as the electrolyte solution, a saturated calomel electrode as the reference electrode, and a carbon rod as the counter electrode. Add 2 mM methylene blue dye to the electrolyte solution and mix the solution. Under oxygen-purifying conditions, use the chronoamperometry method to electrocatalyze the production of hydrogen peroxide to degrade the dye. During the degradation process, take 1 mL of the degradation solution at 5 min, 10 min, 20 min, and 30 min for UV-Vis spectroscopy. Plot the absorbance at 664 nm.

[0053] Application Comparative Example 2 Prepare 50 mL of 2 mM methylene blue dye solution using 3.5 mM sodium chloride solution. Add 100 μL of 30% hydrogen peroxide to the solution and shake well. Degrade the methylene blue dye solution. During the degradation process, take 1 mL of the degradation solution at 5 min, 10 min, 20 min and 30 min respectively for UV-Vis spectroscopy. Plot the absorbance at 664 nm.

[0054] The absorbance graphs for Application Example 3 and Comparative Application Examples 1 and 2 are shown below. Figure 17 As shown, through Figure 17It can be seen that directly using H2O2 for dye degradation (Comparative Example 2) results in a methylene blue dye degradation efficiency of approximately 5%; using the MgO / CuO bimetallic oxide material prepared in Example 1 to electrocatalyze the generation of H2O2 for dye degradation (Comparative Example 1) results in a methylene blue dye degradation efficiency of approximately 12%; using the MgO / CuO bimetallic oxide material prepared in Example 1 for electrocatalytic synergistic Fenton reaction, the electrocatalyzed H2O2 reacts with Fe... 2+ Further, the Fenton reaction generates hydroxyl radicals (·OH), which have strong oxidizing properties. The degradation efficiency of methylene blue dye can reach 100% in 10 min. This shows that the MgO / CuO bimetallic oxide material prepared in Example 1 can rapidly and completely degrade methylene blue in 10 min through electrocatalytic synergistic Fenton reaction, with high degradation efficiency.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A bimetallic oxide material derived from MOF-74, characterized in that, The bimetallic oxide material is a MgO / CuO bimetallic oxide material prepared by pyrolysis using Mg / Cu-MOF-74 as a template.

2. A method for preparing a MOF-74-derived bimetallic oxide material as described in claim 1, characterized in that, Includes the following steps: (1) MgCl2·6H2O, Cu(NO3)2·3H2O and 2,5-dihydroxyterephthalic acid were mixed and dissolved in a mixed solution of N,N-dimethylformamide, ethanol and water, and the reaction was carried out. After the reaction was completed, the reaction system was cooled, and the reaction product was centrifuged, washed and soaked. Finally, after standing, the Mg / Cu-MOF-74 was obtained. (2) The Mg / Cu-MOF-74 is heated and kept at a constant temperature, and then cooled to obtain the MgO / CuO bimetallic oxide material.

3. The preparation method according to claim 2, characterized in that, The ratio of MgCl2·6H2O, Cu(NO3)2·3H2O and 2,5-dihydroxyterephthalic acid used in step (1) is 1.7∶2.0∶1.0; The volume ratio of N,N-dimethylformamide, ethanol, and water is 1.5:1:1; The mass ratio of 2,5-dihydroxyterephthalic acid to N,N-dimethylformamide is 1:(182-183).

4. The preparation method according to claim 2, characterized in that, The reaction in step (1) is carried out at a temperature of 120–160 °C for 16–24 h.

5. The preparation method according to claim 2, characterized in that, The centrifugation speed in step (1) is 7000-8000 rpm, and the time is 5-10 min; The washing process involves washing the centrifuged solid with N,N-dimethylformamide 3 to 5 times. The soaking process involves immersing the washed product in methanol for 3 days, with the methanol being replaced every 12 hours. The settling process involves placing the object in a vacuum at 60 °C for 12 h.

6. The preparation method according to claim 2, characterized in that, The heating and heat preservation in step (2) involves raising the temperature to 800 ℃ at a heating rate of 5 ℃ / min, and then maintaining the temperature at 800 ℃ in an argon atmosphere for 1 h.

7. A method for preparing hydrogen peroxide, characterized in that, Hydrogen peroxide was prepared by electrocatalytic redox reaction using the MOF-74-derived bimetallic oxide material as described in claim 1.

8. A method for sterilizing Pseudomonas aeruginosa, characterized in that, Using the MOF-74-derived bimetallic oxide material as described in claim 1 as a catalyst, an electrocatalytic redox reaction is carried out to generate hydrogen peroxide, which then acts in situ on Pseudomonas aeruginosa for sterilization.

9. A method for rapidly degrading dyes in water, characterized in that, Using the MOF-74-derived bimetallic oxide material as described in claim 1 as a catalyst, an electrocatalytic redox reaction is carried out to generate hydrogen peroxide. Then, ferrous ions are added to water to construct an electrocatalytic-Fenton reaction system to complete the degradation of dyes in water.

10. The method for rapidly degrading dyes in water according to claim 9, characterized in that, The dye is methylene blue dye; The degradation time is 5 to 30 minutes.

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