A method for rapidly preparing CuCe composite metal oxide based on joule heat and application thereof

Abstract

The present application relates to a kind of preparation method of CuCe composite metal oxide based on Joule heat fast preparation and its application.Method is: the Cu salt is mixed with Ce salt and stirred uniformly, then the solution is evaporated, then it is heated by Joule heat momentarily, in situ construction has high concentration asymmetric oxygen vacancy CuCe composite metal oxide catalyst.The method of this instantaneous heating, can effectively avoid the method of traditional scheme preparation CuCe composite metal oxide CuO X Or CeO X Agglomeration, in addition, can be adjusted by adjusting the reaction voltage of Joule heat, electric shock time and reaction atmosphere etc., to adjust the concentration of its active substance, finally improve its reaction activity.The several hours required by traditional calcination method can be shortened to several microseconds to several seconds, greatly reduce time and energy cost, solve the deficiency of traditional hydrothermal method, coprecipitation method or calcination active substance production or sintering.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials technology, and in particular relates to a method for rapidly preparing asymmetric oxygen vacancies in CuCe composite metal oxides based on Joule heating and its application. Background Technology

[0002] In recent years, antibiotic pollution in water bodies has become a global environmental and health crisis. Highly stable antibiotics (such as tetracyclines and sulfonamides) are difficult to degrade effectively by traditional water treatment processes, leading to the spread of antibiotic resistance genes and ecotoxicological effects. Although advanced oxidation technologies (such as photocatalysis and ozone oxidation) have some potential, they generally face problems such as low catalyst efficiency, high cost, and secondary pollution. Therefore, it is crucial to develop novel catalysts that can efficiently activate persulfates (such as PMS) to generate free radicals and achieve rapid mineralization of antibiotics.

[0003] Transition metal oxides, especially Cu / Ce composite systems, are characterized by their unique electronic structures (such as Ce). 3+ / Ce 4+ Cu δ+ The PMS catalyst exhibits great potential in activating antibiotic degradation due to its advantages such as tunable valence state, oxygen storage and release capacity from redox pairs, and strong metal-support interaction (SMSI effect). However, traditional preparation methods (such as solid-phase mixing, hydrothermal methods, co-precipitation, and high-temperature calcination) suffer from drawbacks such as high energy consumption, long processing times, and complex processes. Most critically, they struggle to precisely control oxygen vacancies, particularly the differentiated construction of CuCe asymmetric oxygen vacancies. Studies have shown that CuCe asymmetric oxygen vacancies are active sites for most reactions, effectively enhancing electron transport and transfer. Clearly, current traditional methods for preparing CuCe asymmetric oxygen vacancies limit the improvement of catalyst electron transfer efficiency and performance.

[0004] Joule heating technology utilizes the material's own resistance to achieve instantaneous ultra-high temperatures (up to 1500°C) and ultra-rapid cooling (>10⁻⁶ ppm) within milliseconds (ms) to seconds (s). 4 This technology, with its advanced technology (temperature per ℃ / s), brings revolutionary advantages to catalyst preparation: significantly improving energy and time efficiency (energy consumption can be reduced by 1-2 orders of magnitude), precisely controlling the microstructure (generating high concentrations of defects such as oxygen vacancies, maintaining high specific surface area), and achieving controllable construction of oxygen vacancy concentration and distribution. Although this technology has been widely applied in single metal oxides (such as CuO and CeO2), its application in CuCe bimetallic composite systems and the construction of crucial "asymmetric oxygen vacancies" remains a gap. Given the advantages of Cu / Ce oxides, their asymmetric oxygen vacancies, and Joule heating, this application couples these advantages to prepare CuCe composite oxide asymmetric oxygen vacancy catalysts using the Joule heating method for the efficient degradation of antibiotics in water. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of high cost, long preparation time, and complex preparation steps of existing traditional catalysts, and to provide a novel method for the rapid and large-scale preparation of CuCe composite metal oxides. The prepared CuCe composite oxide catalyst with high concentration of asymmetric oxygen vacancies has good catalytic degradation performance on tetracycline hydrochloride wastewater in water.

[0006] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution:

[0007] This invention synthesizes a CuCe composite metal oxide catalyst with a high concentration of asymmetric oxygen vacancies by adjusting the ratio of copper and cerium salts and changing parameters such as electrostatic discharge voltage, reaction atmosphere, and electrostatic discharge time. The specific technical solution is as follows:

[0008] A method for rapidly preparing asymmetric oxygen vacancies in CuCe composite metal oxides based on Joule heating and its application includes the following steps: Cerium salt and copper salt are dissolved in a mixed solution of distilled water and organic solvent, respectively, to obtain cerium salt solution A and copper salt solution B; then solution B is slowly added dropwise to solution A and continuously mixed and stirred until homogeneous, and then transferred to an oven to evaporate the mixed solvent to obtain copper-cerium mixed powder; finally, the copper-cerium mixed powder is subjected to several pulsed discharges in a self-made Joule heating device under air conditions to finally obtain CuCe composite metal oxides.

[0009] The specific method is as follows:

[0010] (1) Preparation of CuCe mixed salt powder: Weigh copper salt and cerium salt (molar mass ratio of copper salt and cerium salt is 1:0, 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:0.9, 0:1, total molar mass is 10 mmol) and place them in a mixture of distilled water and organic solvent and stir until completely dissolved to form solution A and solution B. Then, slowly add solution B to solution A to form mixed solution C. Stir mixed solution C at room temperature, then transfer it to an oven to dry in order to remove the mixed solution. After drying, cool it to room temperature to finally obtain CuCe composite salt powder for use. The concentration of copper salt in solution A is 0-200 mmol / L. The concentration of cerium salt in solution B is 0-200 mmol / L. In this invention, the concentration of copper salt in solution A and the concentration of cerium salt in solution B are not 0.

[0011] (2) Activation of activated carbon fiber: Cut activated carbon fiber and place it in a Joule heating device, then evacuate the vacuum, and then adjust the voltage and firing time to activate the activated carbon fiber.

[0012] (3) Preparation of CuCe composite metal oxide: Weigh the CuCe mixed salt powder obtained in step (1) and place it in the activated carbon fiber obtained in step (2). Then, bombard it with a certain voltage to dry it. After it is dried, switch the atmosphere to air. Then, adjust the voltage and other parameters and heat it instantaneously to finally obtain CuCe composite metal oxide.

[0013] In the above method, in step (1), the copper salt is copper sulfate; the cerium salt is cerium acetate; the organic solvent is anhydrous ethanol; the total volume of the distilled water and anhydrous ethanol is 50-100 mL; and the volume ratio of the distilled water to anhydrous ethanol is 1:1.

[0014] In the above method, step (2) involves the following preparation method for activating the activated carbon fiber: the activated carbon fiber, with a length and width of 8.0–10 cm × 5.0–6.0 cm, is placed in a Joule heating device, followed by vacuuming; the Joule heating device is as follows: Figure 3 As shown; adjust the voltage to 90-120V, the electric shock time to 0.3-0.7s; the number of electric shock activation cycles to 5-8;

[0015] In the above method, in step (3), the mass of the CuCe mixed salt powder weighed in step (1) is 0.3 to 0.5 g; the drying conditions are a voltage of 50 to 80 V, an electric shock time of 0.3 to 0.7 s, and 5 to 8 electric shocks.

[0016] In the above method, in step (3), the preparation conditions are a voltage of 100-120V, an electric shock time of 0.3-0.7s, and 5-8 electric shocks.

[0017] A CuCe composite metal oxide is characterized in that the CuCe composite metal oxide is still dominated by pure phase CeO2 and no diffraction peak of CuOx is observed. The metal oxide has a high concentration of asymmetric oxygen vacancies and is used to degrade the antibiotic tetracycline hydrochloride. More than 80% of tetracycline can be degraded in 20 minutes.

[0018] CuCe composite metal oxides were used for the degradation of tetracycline antibiotics in water by persulfate degradation.

[0019] Compared with conventional synthesis methods, the CuCe composite metal oxides prepared by this method exhibit more uniform size and morphology, and a more uniform distribution of active sites, thus demonstrating superior catalytic oxidation ability of VOCs and good stability. Compared with traditional methods for preparing CuCe composite metal oxides, the preparation process of this CuCe composite metal oxide catalyst is simple and easy, requiring no additional hydrothermal reaction or water washing, and the reaction is rapid, enabling large-scale preparation in a very short time. It is a CuCe composite metal oxide catalyst with broad application prospects and highly efficient catalytic activity.

[0020] In the above method, in step (1), the copper salt is copper sulfate, and the cerium salt is cerium acetate; the molar mass ratio of the copper salt and cerium salt of a certain molar mass is 1:0, 1:1, 1:3, 1:5, 1:7, 1:9, 0:1, and the total molar mass is 10 mmol; the organic solvent is anhydrous ethanol, and the total volume of the distilled water and anhydrous ethanol is 50 mL; the volume ratio of the distilled water and anhydrous ethanol is 1:1.

[0021] In the above method, in step (2), the length and width of the activated carbon fiber are 8.0cm×5.5cm respectively; the Joule heating device is self-made; the activation voltage is 50-80V, the electric shock time is 0.3-0.7s; and the number of electric shocks is 5-8 times.

[0022] In the above method, in step (3), the mass of the mixed salt powder weighed is 0.3 to 0.5 g; the preparation conditions are a voltage of 100 to 120 V, an electric shock time of 0.3 to 0.7 s, and 5 to 8 electric shocks.

[0023] The CuCe composite metal oxide catalyst prepared in this invention has the characteristics of uniform morphology and size, and uniform dispersion of CuCe active sites; the catalyst can expose more active sites, has strong redox performance, exhibits better catalytic degradation of antibiotics in water, and good stable cycling performance.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] 1. Traditional methods such as hydrothermal precipitation and co-precipitation often require the addition of large amounts of precipitants or complexing agents to precipitate copper and cerium into the corresponding hydroxides. This often results in the precipitants or complexing agents being difficult to clean thoroughly later. Furthermore, the added metal salts are not always completely precipitated due to variations in preparation conditions, leading to waste. In contrast, this preparation method does not require additional precipitants or complexing agents. Drying is sufficient to completely precipitate the added metal salts, followed by Joule heating pulses to prepare the CuCe composite metal oxide, thus achieving full utilization of the added metal salts.

[0026] 2. Traditional methods for preparing metal oxides often require calcination in air, which frequently leads to agglomeration, sintering, or uneven heating, resulting in inconsistent catalytic activity. This new method, however, allows for the rapid preparation of metal oxide catalysts. It effectively suppresses agglomeration and sintering of metal oxides, resulting in more homogeneous reactive components and more exposed active sites, thereby enhancing catalyst activity. Attached Figure Description

[0027] Figure 1 The image shows the XRD pattern of the CuCe oxide obtained in this invention.

[0028] Figure 2 This is a diagram showing the activity of the CuCe composite metal oxide prepared in this invention in degrading tetracycline.

[0029] Figure 3 This is a schematic diagram of the Joule heating device. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. For process parameters not specifically noted, conventional techniques can be referred to.

[0031] In the following embodiments, the Joule heating device includes a quartz glass tube, a graphite electrode 2, a pure copper electrode 3, an in-situ reaction cell 4, a vacuum pump 5, a power supply 6, and a controller 7. Pure copper electrodes 3 are disposed at both ends inside the quartz glass tube, and the graphite electrodes 2 are connected inside the pure copper electrodes 3. A sample 1 is placed between the graphite electrodes 2. The pure copper electrodes 3 are connected to the power supply 6, and the controller 7 is connected in series on the line between the power supply 6 and the pure copper electrodes 3. The quartz glass tube is placed inside the in-situ reaction cell 4, and the in-situ reaction cell 4 is connected to the vacuum pump 5. The controller 7 is used to control the voltage, the electric shock time, and the number of electric shocks.

[0032] Example 1

[0033] (1) Weigh 10 mmol of cerium acetate and dissolve it in a mixture of 50 mL of distilled water and anhydrous ethanol; then stir for 30 min at room temperature. After that, dry it in an oven at 80 °C to obtain powder for later use.

[0034] (2) Cut 8.8cm×5.0cm activated carbon fibers and place them in a Joule heating device for graphitization. Specifically, the activated carbon fibers are electrolyzed 5 times under vacuum conditions and a voltage of 120V, with each electrolysis time being 0.7s.

[0035] (3) Weigh 0.3g of the prepared sample from (1) and place it in the graphitized activated carbon fiber from (2). Then dry it at 50V to remove residual water vapor. Then adjust the voltage to 120V, and the electric shock time is 0.3s. Electric shock is performed 5 times. Finally, vacuum is drawn to cool it rapidly. Then air is injected into the Joule heating reaction cell. Take out the sample and finally obtain a pure phase CeO2 sample for later use.

[0036] Example 2

[0037] 10 mmol of cerium acetate was dissolved in 50 mL of a mixture of distilled water and anhydrous ethanol to obtain solution A. Subsequently, 1, 3, 5, 7, and 9 mmol of copper acetate were dissolved in 50 mL of a mixture of distilled water and anhydrous ethanol to obtain solution B. Solution B was then slowly added to solution A to obtain mixed solution C, and stirred at room temperature for 30 min. The mixture was then dried in an 80°C oven to obtain powder for later use. Subsequent steps were the same as steps (2) and (3) in Example 1, ultimately yielding a series of composite metal oxides with different CuCe ratios for later use. The XRD patterns of the corresponding CuCe composite metal oxides are shown below. Figure 1 As shown, by Figure 1 It can be seen that the corresponding diffraction peaks are all pure CeO2 phase. With the increase of Cu content, some CuO diffraction peaks also appeared, but CeO2 crystal phase still dominates.

[0038] Example 3

[0039] Weigh 60 mg of the metal oxide from the above examples and place it in 100 mL of an aqueous solution containing 20 mg / L tetracycline hydrochloride. Then add 60 mg of potassium peroxymonosulfate and stir continuously at 600 rpm, monitoring the absorbance throughout the stirring process. The resulting activity curve for degrading tetracycline hydrochloride is shown below. Figure 2 As shown, the introduction of Cu can significantly increase the activity of CuCe composite metal oxide in degrading tetracycline. The higher the Cu content, the higher the degradation activity when Ce:Cu is 1:0.7, which can achieve about 85% tetracycline degradation in 10 minutes.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention and are not strict limitations. Those skilled in the art should understand that various changes can be made to the details or form without departing from the spirit and scope of the present invention as defined in the claims.

Claims

1. A method for rapidly preparing CuCe composite metal oxides based on Joule heating, characterized in that, Includes the following steps: (1) Preparation of CuCe mixed salt powder: Weigh copper salt and cerium salt and place them in a mixture of distilled water and organic solvent and stir until completely dissolved to form solution A and solution B. Then, add solution B dropwise to solution A to form mixed solution C. Stir mixed solution C at room temperature and then transfer it to an oven to dry in order to remove the mixed solution. After drying, cool it to room temperature to finally obtain CuCe composite salt powder for use. The concentration of copper salt in solution A is 0-200 mmol / L. The concentration of cerium salt in solution B is 0-200 mmol / L. (2) Activation of activated carbon fiber: Cut activated carbon fiber and place it in a Joule heating device, then evacuate the vacuum, and then adjust the voltage and electric shock time to activate the activated carbon fiber; (3) Preparation of CuCe composite metal oxide: Weigh the CuCe mixed salt powder obtained in step (1) and place it in the activated carbon fiber obtained in step (2). Perform voltage bombardment drying in a Joule heating device. After drying, switch the atmosphere to air. Then adjust the voltage parameters. The preparation conditions are: voltage of 100-120 V, electric shock time of 0.3-0.7 s, electric shock number of times of 5-8 times, and instantaneous heating to obtain CuCe composite metal oxide. In step (2), the activated carbon fiber is prepared by the following method: the activated carbon fiber with a length and width of 8.0-10 cm × 5.0-6.0 cm is placed in a Joule heating device and then a vacuum is drawn; the voltage is adjusted to 90-120 V and the electric shock time is 0.3-0.7 s; the number of electric shock activations is 5-8.

2. The method for rapidly preparing CuCe composite metal oxides based on Joule heating according to claim 1, characterized in that, In step (1), the copper salt is copper sulfate; the cerium salt is cerium acetate; the organic solvent is anhydrous ethanol; the total volume of the distilled water and anhydrous ethanol is 50-100 mL; and the volume ratio of the distilled water to anhydrous ethanol is 1:

1.

3. The method for rapidly preparing CuCe composite metal oxides based on Joule heating according to claim 1, characterized in that, In step (1), the molar mass ratio of copper salt and cerium salt is 1:0.1, 1:0.3, 1:0.5, 1:0.7, 1:0.9, and the total molar mass is 10 mmol.

4. The method for rapidly preparing CuCe composite metal oxides based on Joule heating according to claim 1, characterized in that, In step (3), the mass of CuCe mixed salt powder weighed in step (1) is 0.3 to 0.5 g; the drying conditions are a voltage of 50 to 80 V, an electric shock time of 0.3 to 0.7 s, and 5 to 8 electric shocks.

5. The method for rapidly preparing CuCe composite metal oxides based on Joule heating according to claim 1, characterized in that, The Joule heating device includes a quartz glass tube, a graphite electrode (2), a pure copper electrode (3), an in-situ reaction cell (4), a vacuum pump (5), a power supply (6), and a controller (7). The quartz glass tube has pure copper electrodes (3) at both ends, and the pure copper electrodes (3) are connected to the graphite electrodes (2). A sample (1) is placed between the graphite electrodes (2). The pure copper electrodes (3) are connected to the power supply (6), and the controller (7) is connected in series on the line between the power supply (6) and the pure copper electrodes (3). The quartz glass tube is placed in the in-situ reaction cell (4), and the in-situ reaction cell (4) is connected to the vacuum pump (5). The controller (7) is used to control the voltage, the duration of electric shock, and the number of electric shocks.

6. A CuCe composite metal oxide prepared by the preparation method according to any one of claims 1 to 5, characterized in that, CuCe composite metal oxides are still dominated by pure-phase CeO2, with a high concentration of asymmetric oxygen vacancies.

7. The application of the CuCe composite metal oxide according to claim 6, characterized in that, CuCe composite metal oxides were used for the degradation of tetracycline antibiotics in water by persulfate degradation.

8. The application according to claim 7, characterized in that, More than 80% of tetracycline was degraded in 20 minutes.

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