Preparation method of cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies

Abstract

The present invention discloses a method for synthesizing CeO2 / CoO composite catalyst powder. The preparation method includes the following parts: 1) preparing CoCO3 nanoparticle powder by hydrothermal method; 2) dissolving the CoCO3 powder prepared in 1) and PVP in a mixed solution of water and ethanol, adding Ce(NO3)3·6H2O, heating and stirring until the solution is evaporated to dryness; 3) grinding the dried product in 2) and placing it in a porcelain boat, calcining in a tubular furnace under argon atmosphere to obtain CeO2 / CoO; 4) soaking the powder synthesized in 3) in an aqueous solution of sodium borohydride to increase oxygen vacancies, vacuum filtering, washing and drying to obtain the final catalyst powder. The catalyst prepared by the method of the present invention has a fast catalytic oxidation rate for sulfite, a large selenium adsorption capacity, a simple treatment process, no additional energy consumption, stable effects, can be recycled multiple times, has good environmental and economic benefits, and has broad application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical fields of chemical engineering and preparation of catalytic functional materials, and particularly relates to the application of a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies in the catalytic oxidation of sodium sulfite and the co-adsorption of selenium. Background Art

[0002] With the development of industry and the improvement of people's living standards, the thirst for energy is also increasing continuously. At present, coal is still the main energy consumption in China's energy structure and power structure. Flue gas from coal combustion contains various harmful pollutants, including SO2, NO x , particulate matter, toxic non-metals and heavy metals, which are harmful to human health. Reducing the pollution of flue gas from coal combustion has become an urgent task in today's atmospheric environment governance.

[0003] SO2 in flue gas from coal combustion is the main cause of air pollution, and many flue gas desulfurization processes have been widely applied in industry. Among them, the sodium alkali method desulfurization process uses NaOH solution as the absorbent to absorb SO2 to generate Na2SO3, which not only solves the problem of easy scaling in the tower of the limestone method, but also has a high SO2 absorption efficiency, and is widely applied due to its mature technology, stable operation and high economic benefits. However, in practice, excessive Na2SO3 consumes dissolved oxygen due to insufficient oxidation and is prone to decompose to produce SO2, which may cause high harm to the atmosphere and water in the environment.

[0004] The desulfurization slurry is rich in volatile toxic pollutants from flue gas, including mercury, selenium and arsenic. These pollutants are enriched in the desulfurization slurry, and if discharged, it will cause a large amount of re-emission and secondary environmental risks. Therefore, effectively separating volatile toxic pollutants from the desulfurization slurry is another major challenge, and selenium has become one of the problems that need to be solved urgently in current environmental treatment due to its huge potential toxicity. Summary of the Invention

[0005] Aiming at the problems of a large amount of Na2SO3 generated in the current sodium alkali method desulfurization process and the serious environmental pollution that may be caused by the selenium-rich discharge of the desulfurization slurry, the present invention intends to synthesize a new type of magnetic CeO2 / CoO composite catalyst with rich oxygen vacancies that has both high-efficiency catalytic oxidation of sodium sulfite and co-adsorption of selenium in the desulfurization slurry, so as to reduce the environmental harm in the process of treating flue gas from coal combustion. The preparation method of this catalyst includes: preparation of CoCO3 powder, loading of CeO2 and regulation of rich oxygen vacancies.

[0006] The first object of the present invention is to provide a preparation method of this magnetic nanomaterial with rich oxygen vacancies. The process involved in this method is simple, non-toxic and environmentally friendly, and is suitable for popularization and application.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A preparation method of a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies, comprising the following steps:

[0009] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution, stir well and then hydrothermally react in a reaction kettle; then, centrifuge, wash, and dry the hydrothermally reacted product to obtain purple powder;

[0010] 2) Disperse a certain amount of the purple powder prepared in 1) in an ethanol-water solution, add 0.7 g of polyvinylpyrrolidone, stir well to dissolve, and then add cerium nitrate hexahydrate powder to form a mixed solution; heat and stir the above solution for reaction, centrifuge, wash, and dry to obtain pink powder;

[0011] Calcine the pink powder in 2) under a protective atmosphere to obtain a cobalt-cerium bimetallic magnetic nanomaterial;

[0012] Calcine the pink powder in 2) under a protective atmosphere to obtain a cobalt-cerium bimetallic magnetic nanomaterial;

[0013] Soak the calcined powder in 3) in a sodium borohydride solution for 1 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial catalyst with rich oxygen vacancies.

[0014] Further, the hydrothermal temperature in step 1) is 180 °C and the reaction time is 12 h.

[0015] Further, the detergent used for washing the product in step 1) is ethanol.

[0016] Further, the molar ratio of cobalt carbonate to cerium nitrate hexahydrate in step 2) is 1∶(0.04 - 0.8).

[0017] Further, the stirring reaction temperature in step 2) is 40 - 60 °C and the reaction time is 12 - 18 h.

[0018] Further, the drying temperature in step 2) is 80 - 100 °C and the drying time is 10 - 12 h.

[0019] Further, the calcination temperature in step 3) is 500 - 700 °C and the drying time is 3 - 4 h.

[0020] Further, the concentration of sodium borohydride in step 4) is 0.05 - 0.1 mol / L.

[0021] The second object of the present invention is to provide a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies prepared by the above method.

[0022] The third object of the present invention is to provide the application of the cobalt-cerium bimetallic magnetic nanomaterial carbon material with rich oxygen vacancies prepared by the above-mentioned method in the catalytic oxidation of sodium sulfite and the synergistic adsorption of selenium.

[0023] The present invention first synthesizes cobalt carbonate by a hydrothermal method, and then deposits cerium nitrate on the surface of spherical cobalt carbonate by a deposition method to endow cobalt carbonate with active sites. After calcination, a CeO2 / CoO bimetallic composite material is formed, and then it is soaked in a sodium borohydride solution to obtain a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) The present invention prepares a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies. This material has a spherical structure, and cobalt and cerium oxide active sites are evenly distributed on the surface.

[0026] 2) The cobalt-cerium bimetallic oxide material prepared by the present invention has strong magnetism and is easy to recycle. The composite material prepared by the present invention uses the synergistic effect of cobalt and cerium bimetals to catalytically oxidize sodium sulfite. The synergistic effect helps the multi-component hybrid structure to exhibit excellent catalytic performance far superior to its corresponding single component. CeO2 nanoparticles will release lattice oxygen to become surface adsorbed oxygen, and part of the Ce in the crystal 4+ part will become Ce 3+ , forming oxygen vacancies, and under oxygen-rich conditions, the adsorbed oxygen will be converted into lattice oxygen and stored. Ce 3+ will change back to Ce 4+ , strengthening the mass transfer process and effectively improving the catalytic reaction rate of sodium sulfite; moreover, the presence of CeO2 nanoparticles enhances the adsorption capacity of the composite material for selenium in the desulfurization slurry.

[0027] 3) The cobalt-cerium bimetallic oxide material prepared by soaking in a sodium borohydride solution in the present invention is endowed with oxygen vacancies, further enhancing the ability to catalytically oxidize sodium sulfite. Moreover, this catalyst has a strong selenium adsorption capacity, realizing the synergistic control of the catalytic oxidation of sodium sulfite and selenium adsorption in the desulfurization slurry; the preparation conditions of this catalyst are mild, the operation steps are simple, the process is green and environmentally friendly, and it has great application potential.

[0028] 4) Since the prepared CeO2 / CoO has strong magnetism, the catalyst can be directly recycled using a magnet, and the recycled catalyst still has good catalytic activity. The reusability of CeO2 / CoO in the oxidation of Na2SO3 was evaluated by adding a regenerated sample with the same concentration as under normal conditions. After three cycles of evaluation, the oxidation rate decreased from 0.1735 mol / (L·s) to 0.1124 mol / (L·s), but still had a relatively high oxidation rate. Therefore, it can be judged that CeO2 / CoO can be reused with high catalytic activity, which greatly reduces the cobalt usage and thus lowers the cost. Description of the Drawings

[0029] Figure 1 is the XRD pattern of OV-70wt%-CeO2 / CoO obtained in Example 1;

[0030] Figure 2 is the SEM scanning electron microscope image of OV-70wt%-CeO2 / CoO obtained in Example 1;

[0031] Figure 3 is the XRD pattern of 70wt%-CeO2 / CoO obtained in Comparative Example 1;

[0032] Figure 4 is the ESR spectrum of the product obtained in Example 1 and the product obtained in Comparative Example 1;

[0033] Figure 5 is the XRD pattern of the product CoO obtained in Comparative Example 2;

[0034] Figure 6 is the XRD pattern of the product CeO2 obtained in Comparative Example 3;

[0035] Figure 7 is the saturation adsorption capacity diagram of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies prepared in Example 1 at different initial selenium concentrations. Detailed Embodiments

[0036] The following are some examples to illustrate the technical solutions described in this application. It is only an explanation of this technical solution for understanding and cannot limit this application. This application can be implemented in many different ways defined and covered by the claims.

[0037] Example 1

[0038] A cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies, and its preparation method is as follows:

[0039] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution. After stirring well, place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifugate, wash, and dry the hydrothermal product to obtain purple powder CoCO3;

[0040] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol - aqueous solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 2.46 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0041] 3) Heat - stir - react the above solution at 50 °C, then centrifugate, wash, and dry to obtain pink powder;

[0042] 4) Under an argon atmosphere, heat the above - prepared pink powder at a heating rate of 5 °C / min to 600 °C and calcine for 3 h to obtain a cobalt - cerium bimetallic magnetic nanomaterial (70 wt% - CeO2 / CoO);

[0043] 5) Immerse the powder calcined in 4) in a 0.05 mol / L sodium borohydride solution for 1 h to obtain a cobalt - cerium bimetallic magnetic nanomaterial catalyst with rich oxygen vacancies (OV - 70 wt% - CeO2 / CoO).

[0044] Perform X - ray diffraction analysis on the product obtained in this example, and the results are shown in Figure 1 , and the characteristic peaks of the product obtained in the figure are consistent with the standard spectra of cobalt oxide (PDF#75 - 0393) and cerium dioxide (PDF#81 - 0792). It can be seen from Figure 2 that the synthesized cobalt - cerium bimetallic magnetic nanomaterial is in a spherical structure.

[0045] Example 2

[0046] A cobalt - cerium bimetallic magnetic nanomaterial with rich oxygen vacancies, and its preparation method is as follows:

[0047] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution. After stirring well, place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifugate, wash, and dry the hydrothermal product to obtain purple powder CoCO3;

[0048] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol - aqueous solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 0.12 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0049] 3) Heat and stir the above solution at 50 °C for reaction, centrifuge, wash, and dry to obtain a pink powder;

[0050] 4) Under an argon atmosphere, heat the above-prepared pink powder at a heating rate of 5 °C / min to 600 °C and calcine for 3 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial (10 wt% - CeO2 / CoO);

[0051] 5) Immerse the powder calcined in 4) in a 0.05 mol / L sodium borohydride solution for 1 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial catalyst with oxygen-rich vacancies (OV-10 wt% - CeO2 / CoO).

[0052] Example 3

[0053] A cobalt-cerium bimetallic magnetic nanomaterial with oxygen-rich vacancies, and its preparation method is as follows:

[0054] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution, stir well and then place in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifuge, wash, and dry the hydrothermal product to obtain a purple powder CoCO3;

[0055] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol-water solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 0.45 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0056] 3) Heat and stir the above solution at 50 °C for reaction, centrifuge, wash, and dry to obtain a pink powder;

[0057] 4) Under an argon atmosphere, heat the above-prepared pink powder at a heating rate of 5 °C / min to 600 °C and calcine for 3 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial (30 wt% - CeO2 / CoO);

[0058] 5) Immerse the powder calcined in 4) in a 0.05 mol / L sodium borohydride solution for 1 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial catalyst with oxygen-rich vacancies (OV-30 wt% - CeO2 / CoO).

[0059] Example 4

[0060] A cobalt-cerium bimetallic magnetic nanomaterial with oxygen-rich vacancies, and its preparation method is as follows:

[0061] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution. After stirring well, place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifuge, wash, and dry the hydrothermal product to obtain purple powder CoCO3;

[0062] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol - aqueous solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 1.06 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0063] 3) Heat, stir, react, centrifuge, wash, and dry the above solution at 50 °C to obtain pink powder;

[0064] 4) Under an argon atmosphere, heat the above - prepared pink powder to 600 °C at a heating rate of 5 °C / min and calcine for 3 h to obtain a cobalt - cerium bimetallic magnetic nanomaterial (50 wt% - CeO2 / CoO);

[0065] 5) Immerse the powder calcined in 4) in a 0.05 mol / L sodium borohydride solution for 1 h to obtain a cobalt - cerium bimetallic magnetic nanomaterial catalyst with oxygen - rich vacancies (OV - 50 wt% - CeO2 / CoO).

[0066] Example 5

[0067] A cobalt - cerium bimetallic magnetic nanomaterial with oxygen - rich vacancies, and its preparation method is as follows:

[0068] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution. After stirring well, place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifuge, wash, and dry the hydrothermal product to obtain purple powder CoCO3;

[0069] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol - aqueous solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 9.798 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0070] 3) Heat, stir, react, centrifuge, wash, and dry the above solution at 50 °C to obtain pink powder;

[0071] 4) Under an argon atmosphere, heat the above - prepared pink powder to 600 °C at a heating rate of 5 °C / min and calcine for 3 h to obtain a cobalt - cerium bimetallic magnetic nanomaterial (90 wt% - CeO2 / CoO);

[0072] 5) Immerse the calcined powder in step 4) in a 0.05 mol / L sodium borohydride solution for 1 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial catalyst with oxygen-rich vacancies (OV-90wt%-CeO2 / CoO).

[0073] Comparative Example 1

[0074] A cobalt-cerium bimetallic magnetic nanomaterial, and its preparation method is as follows:

[0075] 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution, stir well, and then place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifuge, wash, and dry the hydrothermal product to obtain a purple powder CoCO3;

[0076] 2) Disperse 0.9 g of the above purple powder CoCO3 in an ethanol-water solution (formed by mixing 20 mL of ethanol and 20 mL of water), add 0.7 g of polyvinylpyrrolidone, stir and dissolve well, and then add 2.46 g of cerium nitrate hexahydrate powder to form a mixed solution;

[0077] 3) Heat, stir, react, centrifuge, wash, and dry the above solution at a temperature of 50 °C to obtain a pink powder;

[0078] 4) Under an argon atmosphere, heat the above-prepared pink powder at a heating rate of 5 °C / min to 600 °C, calcine for 3 h, and cool to room temperature to obtain a cobalt-cerium bimetallic magnetic nanomaterial (70wt%-CeO2 / CoO);

[0079] Perform XRD characterization on the product obtained in this comparative example, and the results are shown in Figure 3 , and the characteristic crystal phase peaks of cobalt oxide (PDF#75-0393) and cerium dioxide (PDF#81-0792) can be observed from the figure; perform ESR characterization, and the results are shown in Figure 4 , and it can be observed from the figure that the intensity of the oxygen vacancy characteristic peak of the product obtained in the comparative example is significantly lower than that of the oxygen vacancy characteristic peak of the cobalt-cerium bimetallic magnetic nanomaterial with oxygen vacancies in Example 1. The results show that the number of oxygen holes in the catalyst soaked in the sodium borohydride solution increases and the oxidation rate increases.

[0080] Comparative Example 2

[0081] A cobalt oxide nanomaterial, and its preparation method is as follows:

[0082] Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution, stir well, and then place it in a reaction kettle for hydrothermal treatment (180 °C, 12 h); then centrifuge, wash, and dry the hydrothermal product to obtain a purple powder CoCO3;

[0083] Place the above purple powder CoCO3 under an argon atmosphere and heat it to 600 °C at a heating rate of 5 °C / min, calcine for 3 h, and cool to room temperature to obtain cobalt oxide nanomaterials.

[0084] Perform XRD characterization on the product obtained in this comparative example, and the results are shown in Figure 5 , and the characteristic crystal phase peaks of cobalt oxide (PDF#75-0393) can be observed from the figure.

[0085] Comparative Example 3

[0086] A cerium dioxide nanomaterial, and its preparation method is as follows:

[0087] Place cerium nitrate hexahydrate under an argon atmosphere and heat it to 600 °C at a heating rate of 5 °C / min, calcine for 3 h, and cool to room temperature to obtain cerium dioxide nanomaterials.

[0088] Perform XRD characterization on the product obtained in this comparative example, and the results are shown in Figure 6 , and the characteristic crystal phase peaks of cerium dioxide (PDF#81-0792) can be observed from the figure.

[0089] Application Example

[0090] Apply the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies obtained in Example 1 to the experiment of catalytic oxidation of sodium sulfite and synergistic adsorption of selenium, which specifically includes the following steps:

[0091] In this experiment, a bubbling reactor was used. Weigh 0.05 g of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies and add it to 200 mL of deionized water, and then introduce air with a gas flow rate of 1 L / min and heat it in a constant temperature water bath at 45 °C; add 10 g of sodium sulfite and a selenium solution of 1 ppm, adjust the pH of the solution to 8, and start timing; take samples every 5 min, successively extract 2.5 mL, 2 mL, 1.5 mL, 1 mL, and 1 mL of the solution and place them in a 100 mL volumetric flask, add 1 mL of hydrochloric acid solution (1:1), fix the volume and shake well. Measure 50 mL of the solution and place it in a beaker, add 2.5 mL of stabilizer and 0.2 g of barium chloride, stir for 1 min and then let it stand for 4 min, measure the absorbance with a spectrophotometer at a wavelength of 420 nm, calculate the sulfate ion concentration in the solution at different times, and after diluting the solution 100 times, measure the remaining selenium concentration in the solution after synergistic adsorption by atomic fluorescence.

[0092] In this adsorption experiment, 100 mL of selenium solutions with concentrations of 20 ppm, 40 ppm, 60 ppm, 80 ppm, 100 ppm, and 120 ppm were respectively prepared, the pH was adjusted to 8, 0.05 g of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies was added, and stirred for 24 h to measure the saturated adsorption capacity at different initial selenium concentrations.

[0093] Table 1 is a comparison table of the catalytic rates of the catalytic oxidation of sodium sulfite in Examples 1-5, Comparative Examples 1-3 and the obtained products

[0094]

[0095]

[0096] It can be seen from Table 1 that the oxidation rate of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies is 0.17 mmol / (L·s). Compared with the oxidation rates of the cobalt-cerium bimetallic magnetic nanomaterial (prepared in Comparative Example 1), cobalt oxide nanomaterial (prepared in Comparative Example 2), and cerium dioxide nanomaterial (prepared in Comparative Example 3), it is increased by 0.99, 7.56 and 15.14 times respectively, and the catalytic oxidation efficiency is significantly improved; Figure 4 is the electron spin resonance spectrum of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies (prepared in Example 1) and the cobalt-cerium bimetallic magnetic nanomaterial (prepared in Comparative Example 1). It can be clearly observed that the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies modified by sodium borohydride has a higher oxygen vacancy intensity. Moreover, the efficiency of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies in synergistically adsorbing selenium in sodium sulfite can reach 87.47%.

[0097] Figure 7 is the saturation adsorption capacity diagram of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies prepared in Example 1 at different initial selenium concentrations. It can be seen that the saturation adsorption capacity of this catalyst for selenium is as high as 173.08 mg / g. And in a 50 g / L sodium sulfite solution (pH = 8), while ensuring a catalytic oxidation rate of 0.17 mmol / (L·s), it can synergistically adsorb up to 87.47% of the selenium in the solution, thus achieving the effect of synchronous removal of the two.

[0098] The above are only the implementation examples of this method and cannot limit the scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention, so all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention shall be defined by the claims and shall be included within the protection scope of the present invention.

Claims

1. Application of a cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies in catalytic oxidation of sodium sulfite and synergistic adsorption of selenium, and a preparation method of the cobalt-cerium bimetallic magnetic nanomaterial with rich oxygen vacancies, comprising the following steps: 1) Disperse 5.8 g of cobalt nitrate hexahydrate and 3 g of urea in 80 mL of ethylene glycol solution, stir well and then hydrothermally react in a reaction kettle; then, centrifuge, wash, and dry the product after hydrothermal reaction to obtain a purple powder; 2) Disperse 0.9 g of the purple powder prepared in 1) in an ethanol aqueous solution, add 0.7 g of polyvinylpyrrolidone, stir well to dissolve, and then add 2.46 g of cerium nitrate hexahydrate powder to form a mixed solution; heat and stir the above solution for reaction, centrifuge, wash, and dry to obtain a pink powder; 3) Calcinate the pink powder in 2) under a protective atmosphere to obtain a cobalt-cerium bimetallic magnetic nanomaterial; 4) Immerse the calcined powder in 3) in a sodium borohydride solution for 1 h to obtain a cobalt-cerium bimetallic magnetic nanomaterial catalyst with rich oxygen vacancies.

2. The application according to claim 1, wherein, The hydrothermal temperature in step 1) is 180 °C, and the reaction time is 12 h.

3. The application according to claim 1, characterized in that, The detergent used for washing the product in step 1) is ethanol.

4. The application according to claim 1, wherein The stirring reaction temperature in step 2) is 40-60 °C, and the reaction time is 12-18 h.

5. The application according to claim 1, wherein The drying temperature in step 2) is 80-100 °C, and the drying time is 10-12 h.

6. The application according to claim 1, characterized in that, The calcination temperature in step 3) is 500-700 °C, and the drying time is 3-4 h.

7. The application according to claim 1, characterized in that, The concentration of sodium borohydride in step 4) is 0.05-0.1 mol / L.

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