Cerium oxide-gold nano catalytic material and preparation method thereof

Abstract

The embodiment of the invention provides a cerium oxide-gold nano catalytic material and a preparation method thereof, and the preparation method comprises the following steps: adding weak acid and strong alkali weak acid salt into deionized water, and uniformly stirring to obtain a buffer solution; adding a cerium source and a gold source into the buffer solution, and uniformly stirring to form a mixed solution; after the mixed solution is subjected to a photo-reduction reaction, the mixed solution is moved into a hydrothermal reaction kettle to be subjected to a hydrothermal reaction, and a cerium oxide-gold mixture is obtained; after the cerium oxide-gold mixture is cooled to the room temperature, precipitates are obtained through centrifugation; washing the precipitate with deionized water for multiple times, and drying to obtain a cerium oxide-gold nano catalytic material; wherein the cerium oxide-gold nano catalytic material comprises cerium dioxide and nano-gold loaded on the surface of the cerium dioxide, the cerium dioxide and the nano-gold are spherical or sphere-like, and the particle size of the cerium dioxide and the particle size of the nano-gold are both 3-15 nm. The preparation method disclosed by the embodiment of the invention is simple, and the prepared cerium oxide-gold nano catalytic material is relatively high in catalytic performance.

Description

Technical Field

[0001] The present application relates to the technical field of photocatalytic materials, and in particular to a cerium oxide-gold nanocatalytic material and a preparation method thereof. Background Art

[0002] While cars bring immense convenience to people's lives and work, they can also inadvertently cause some physical harm to passengers. For example, new cars, and even older ones, continuously release harmful substances such as formaldehyde, toluene, and total volatile organic compounds (TVOCs). Formaldehyde harms the human nervous and immune systems and is designated a carcinogen by the World Health Organization. Long-term exposure to excessive formaldehyde can lead to leukemia, cancer, asthma, and other diseases. Furthermore, viruses like influenza are primarily transmitted directly and through aerosols, and cars, as confined spaces, are highly susceptible to the growth of bacteria and viruses, posing a health threat to passengers. Therefore, improving the in-car environment has become an urgent task.

[0003] According to different disinfection principles, in-vehicle air disinfection technology can be divided into ozone disinfection, chemical disinfection and activated carbon disinfection, but these methods all have some obvious disadvantages, which limit their practical application and development. In recent years, photocatalytic materials represented by cerium dioxide and titanium dioxide have been widely used as antibacterial agents. When photocatalytic materials are irradiated by light, the electrons in the valence band (e - ) absorbs photon energy and moves to the conduction band within femtoseconds, becoming freely moving conduction band electrons. At the same time, the same number of holes (h + ), which are usually called photogenerated carriers, that is, electron-hole pairs with extremely short lifespan. - and h + It can be transferred to the surface of the photocatalytic material through diffusion or the action of the space electric field, and undergo corresponding redox reactions to produce reactive oxygen species (ROS). The highly oxidizing ROS will react with the formaldehyde in the car to produce carbon dioxide and water. At the same time, ROS will also destroy the cell structure of microorganisms such as bacteria and viruses, causing cell damage and death, thereby improving the driving environment. However, if the light source energy is insufficient to excite the photocatalytic material, the photogenerated e - and h + Recombination will occur inside or on the surface of the photocatalytic material without participating in any reaction, and the energy generated will be released in the form of heat.

[0004] As a commonly used photocatalyst, cerium dioxide has sufficient oxygen vacancies and high oxygen storage and release capacity. 3+ / Ce 4+It is reversible, so its catalytic performance is excellent. However, ceria is a wide-bandgap semiconductor that only absorbs ultraviolet light, less than 5% of the solar spectrum energy, which limits the photocatalytic efficiency of ceria. In order to improve the utilization of sunlight by ceria, loading precious metal nanoparticles (such as Au and Ag) on ​​ceria as a catalyst is a favorable choice to improve the photoactivity of ceria. This is mainly due to the precious metal nanoparticles with localized surface plasmon resonance (LSPR) effect, which allows most sunlight and indoor light to provide photocatalytic ability.

[0005] However, in the related art, the synthesis conditions of cerium oxide-nano-gold catalyst are harsh and the process is complicated. In addition, the photocatalytic ability of cerium dioxide depends on the Ce 3+ / Ce 4+ The smaller the particles, the more Ce 3+ The higher the concentration, the stronger the catalytic performance. However, the particle size of the cerium oxide-nano-gold catalyst in the related art is too large, and the catalytic performance is relatively poor. Summary of the Invention

[0006] In view of this, the embodiments of the present application hope to provide a cerium oxide-gold nanocatalytic material and a preparation method thereof, which has a simple preparation method and strong catalytic performance.

[0007] To achieve the above objectives, an embodiment of the present application provides a method for preparing a cerium oxide-gold nanocatalytic material, comprising the following steps:

[0008] S01, adding a weak acid and a strong base weak acid salt to deionized water, stirring evenly to obtain a buffer solution;

[0009] S02, adding the cerium source and the gold source to the buffer solution, and stirring to form a mixed solution;

[0010] S03, after subjecting the mixed solution to a photoreduction reaction, transferring the mixed solution to a hydrothermal reaction vessel for a hydrothermal reaction to obtain a cerium oxide-gold mixture;

[0011] S04, after the cerium oxide-gold mixture is cooled to room temperature, centrifuging to obtain a precipitate;

[0012] S05. Wash the precipitate with deionized water several times and then dry it to obtain a cerium oxide-gold nanocatalytic material; wherein the cerium oxide-gold nanocatalytic material includes cerium dioxide and nano-gold supported on the surface of the cerium dioxide, the cerium dioxide and the nano-gold are both spherical or quasi-spherical, and the particle size of the cerium dioxide and the particle size of the nano-gold are both 3nm-15nm.

[0013] The cerium dioxide and nano-gold mentioned above refer to cerium dioxide nanoparticles and nano-gold particles. That is to say, the cerium oxide-gold nanocatalytic material prepared in this application refers to a nanocatalytic material containing cerium dioxide and nano-gold, and the particle size of cerium dioxide and nano-gold is between 3nm and 15nm.

[0014] The quasi-spherical shape means that the shape of the cerium dioxide nanoparticles and / or the gold nanoparticles can be approximately spherical.

[0015] The particle size of ceria refers to the particle size of ceria nanoparticles, and the particle size of gold nanoparticles refers to the particle size of precious metal nanoparticles.

[0016] The preparation method utilizes the reducing properties of a strong base and a weak acid salt to react with a gold source to form gold nanoparticles. Simultaneously, a photoreduction reaction is used to completely reduce any unreacted gold source in the mixed solution to form gold nanoparticles. Under high temperature and high pressure, the cerium source slowly nucleates and crystallizes to form ceria nanoparticles. Finally, the ceria nanoparticles and gold nanoparticles undergo electrostatic adsorption to form a ceria-gold nanocatalytic material.

[0017] In one embodiment, the weak acid is one or a combination of at least two of acetic acid, glacial acetic acid, and citric acid.

[0018] In one embodiment, the strong base weak acid salt is one or a combination of sodium acetate and sodium citrate.

[0019] In one embodiment, the pH value of the buffer solution is 4-6 to ensure that the solution remains stable after the cerium source and the gold source enter the reaction system, thereby promoting subsequent reactions.

[0020] In one embodiment, the stirring time in step S01 is 5 min-20 min.

[0021] In one embodiment, the cerium source is one or a combination of at least two of ammonium cerium nitrate, cerium acetate, and cerium chloride heptahydrate.

[0022] In one embodiment, the gold source is one or a combination of chloroauric acid and gold acetate.

[0023] In one embodiment, the photoreduction reaction is performed by irradiating with a xenon lamp for 10 min to 30 min.

[0024] In one embodiment, the temperature of the hydrothermal reaction is 150° C.-250° C., and the reaction time is 12 h-24 h.

[0025] The temperature and reaction time can effectively control the nucleation and growth rates of the cerium oxide-gold nanoparticles.

[0026] In one embodiment, the drying temperature in step S01 is 30° C.-80° C., and the drying time is 4 h-15 h, so as to facilitate the removal of moisture.

[0027] Another embodiment of the present application provides a cerium oxide-gold nanocatalytic material, which is prepared by the preparation method described above.

[0028] In one embodiment, the particle size of the cerium dioxide is 3 nm to 10 nm.

[0029] The particle size of the gold nanoparticles can also be 3nm-10nm.

[0030] The preparation method of the present application has the following advantages:

[0031] 1. The cerium oxide-gold nanocatalytic material is prepared using a one-step hydrothermal method. This method is simple, utilizes a wide range of raw materials, and is suitable for large-scale industrial production. This preparation method does not use surfactants, effectively preventing the impact of surfactants or coatings on subsequent reactions. Furthermore, the lack of wastewater effectively protects the environment, making it green and safe. Furthermore, this preparation method does not employ a high-temperature sintering process, which reduces the size and aggregation of the ceria and gold nanoparticles in the cerium oxide-gold nanocatalytic material.

[0032] 2. The particle size of cerium dioxide in the cerium oxide-gold nanocatalytic material synthesized by this preparation method is less than 15nm (most of which is less than 10nm) and is relatively uniformly dispersed. 3+ The high content and many defects on the surface of cerium dioxide nanoparticles have higher visible light absorption and conversion capabilities, enhance the formation of oxygen vacancies, promote the generation of ROS under visible light, and improve the photocatalytic ability.

[0033] 3. The cerium oxide-gold nanocatalytic material of the embodiment of the present application has a good photocatalytic effect and can achieve antibacterial and photocatalytic effects on formaldehyde under visible light irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 TEM image of the cerium oxide-gold nanocatalytic material prepared in Example 1;

[0035] Figure 2 This is a HRTEM image of the cerium oxide-gold nanocatalytic material prepared in Example 1;

[0036] Figure 3 This is the EDS image of the cerium oxide-gold nanocatalytic material prepared in Example 1;

[0037] Figure 4 This is the IV curve of the cerium oxide-gold nanocatalytic material prepared in Example 1. DETAILED DESCRIPTION

[0038] The technical solution of this application is further described in detail below with reference to specific embodiments:

[0039] Example 1

[0040] (1) Add 10 mL of glacial acetic acid and 10 g of sodium acetate to 80 mL of deionized water and stir for 10 min to obtain a buffer solution.

[0041] (2) Add 2.7 g of ammonium cerium nitrate and 0.5 M chloroauric acid to the buffer solution of step (1) and stir for 10 min to form a mixed solution.

[0042] (3) The mixed solution was irradiated with a xenon lamp for 20 minutes and then transferred to a hydrothermal reactor, heated to 200°C, and maintained for 24 hours to obtain a cerium oxide-gold mixture.

[0043] (4) After the cerium oxide-gold mixture is cooled to room temperature, it is centrifuged to obtain a precipitate.

[0044] (5) The precipitate was washed with deionized water several times and then placed in an oven for drying at a drying temperature of 40°C for 10 h to obtain a cerium oxide-gold nanocatalytic material.

[0045] The cerium oxide-gold nanocatalytic material was characterized by TEM (transmission electron microscopy) and EDS (energy dispersive spectrometer), and the TEM characterization and HRTEM (high resolution transmission electron microscopy) characterization were as follows: Figure 1 and 2 As shown in Figure 2, the synthesized cerium oxide-gold nanocatalytic material is dispersed relatively evenly, and the particle size of cerium dioxide is less than 10nm. At the same time, spherical gold nanoparticles with a diameter slightly less than 5nm can be seen evenly distributed on the surface of the carrier. EDS characterization is shown in Figure 2. Figure 3 As shown in the figure, diffraction peaks of Ce, O and Au elements can be seen. The above results all indicate that the cerium oxide-gold nanocatalytic material was successfully synthesized and has a small size.

[0046] Example 2

[0047] (1) Add 10 mL of citric acid and 10 g of sodium citrate to 80 mL of deionized water and stir for 10 min to obtain a buffer solution.

[0048] (2) Add 2.7 g of ammonium cerium nitrate and 0.5 M chloroauric acid to the buffer solution of step (1) and stir for 10 min to form a mixed solution.

[0049] (3) The mixed solution was irradiated with a xenon lamp for 20 minutes and then transferred to a hydrothermal reactor, heated to 200°C, and maintained for 24 hours to obtain a cerium oxide-gold mixture.

[0050] (4) After the cerium oxide-gold mixture is cooled to room temperature, it is centrifuged to obtain a precipitate.

[0051] (5) The precipitate was washed with deionized water several times and then placed in an oven for drying at a drying temperature of 40°C for 10 h to obtain a cerium oxide-gold nanocatalytic material.

[0052] Example 3

[0053] (1) Add 10 mL of glacial acetic acid and 10 g of sodium acetate to 80 mL of deionized water and stir for 10 min to obtain a buffer solution.

[0054] (2) Add 2.7 g of ammonium cerium nitrate and 0.5 M chloroauric acid to the buffer solution of step (1) and stir for 10 min to form a mixed solution.

[0055] (3) The mixed solution was irradiated with a xenon lamp for 20 minutes and then transferred to a hydrothermal reactor, heated to 220°C, and maintained for 20 hours to obtain a cerium oxide-gold mixture.

[0056] (4) After the cerium oxide-gold mixture is cooled to room temperature, it is centrifuged to obtain a precipitate.

[0057] (5) The precipitate was washed with deionized water several times and then placed in an oven for drying at a drying temperature of 40°C for 10 h to obtain a cerium oxide-gold nanocatalytic material.

[0058] Example 4

[0059] (1) Add 10 mL of glacial acetic acid and 10 g of sodium acetate to 80 mL of deionized water and stir for 10 min to obtain a buffer solution.

[0060] (2) Add 2.7 g of ammonium cerium nitrate and 0.5 M chloroauric acid to the buffer solution of step (1) and stir for 10 min to form a mixed solution.

[0061] (3) The mixed solution was irradiated with a xenon lamp for 20 minutes and then transferred to a hydrothermal reactor, heated to 200°C, and maintained for 24 hours to obtain a cerium oxide-gold mixture.

[0062] (4) After the cerium oxide-gold mixture is cooled to room temperature, it is centrifuged to obtain a precipitate.

[0063] (5) The precipitate was washed several times with deionized water and then placed in an oven for drying at a drying temperature of 60°C for 8 h to obtain a cerium oxide-gold nanocatalytic material.

[0064] Comparative Example 1

[0065] (1) Add 10 mL of glacial acetic acid and 10 g of sodium acetate to 80 mL of deionized water and stir for 10 min to obtain a buffer solution.

[0066] (2) Add 2.7 g of ammonium cerium nitrate to the buffer solution of step (1) and stir for 10 min to form a mixed solution.

[0067] (3) The mixed solution was transferred to a hydrothermal reactor, heated to 200° C., and maintained for 24 h to obtain a cerium dioxide mixture.

[0068] (4) After the cerium dioxide mixture is cooled to room temperature, it is centrifuged to obtain a precipitate.

[0069] (5) The precipitate was washed with deionized water several times and then placed in an oven for drying at a drying temperature of 40°C for 10 h to obtain cerium dioxide nanoparticles.

[0070] Test and results:

[0071] (1) Particle size analysis

[0072] The particle size was measured using a particle size analyzer (DLS), and the detection time for a single sample was 2 minutes.

[0073] The particle size of ceria in the synthesized ceria-gold nanocatalytic material was measured by DLS. The results are shown in Table 1. The average particle size in Table 1 refers to the average particle size of the individual samples as a whole. As can be seen from the table, the particle size of ceria in the ceria-gold nanocatalytic material is consistently less than 15 nm. It should be noted that DLS particle size measurements generally slightly exceed the actual size of the material because the material is dispersed in water during testing, leaving a layer of water film covering the surface.

[0074] Table 1 Sample hydration particle size test results

[0075] sample Average particle size (nm) Comparative Example 1 7 Example 1 9 Example 2 11 Example 3 10 Example 4 10

[0076] (2) Morphology and elemental characterization

[0077] Transmission electron microscopy (TEM) was used to characterize the size, morphology, and dispersibility of the cerium oxide-gold nanocatalyst. The cerium oxide-gold nanocatalyst was dispersed in deionized water and sonicated for 10 minutes. A drop of the suspension was then placed on a copper mesh. After natural drying, the mesh was placed under a TEM to obtain a TEM image.

[0078] The size and morphology of cerium oxide-gold nanocatalytic materials were observed by TEM. Figure 1 It can be observed that the prepared cerium oxide-gold nanocatalytic material is dispersed relatively evenly and the particle size of cerium dioxide is less than 10 nm. At the same time, spherical gold nanoparticles with a diameter slightly less than 5 nm are evenly distributed on the surface of the carrier.

[0079] Figure 2Two clear stripes perpendicular to the axis of the nanoparticles appeared simultaneously. The interplanar spacing d of the cubic phase is 0.236nm, which is consistent with the (111) crystal plane of the Au cubic phase; the interplanar spacing d of the cubic phase is 0.27nm, which is consistent with the (200) crystal plane of cerium oxide. This shows that cerium dioxide and gold can be easily and successfully composited by a simple hydrothermal method. At the same time, the elemental composition of the cerium oxide-gold nanocatalytic material was analyzed by EDS, which is usually used together with a scanning electron microscope or a transmission electron microscope. From Figure 3 The diffraction peaks of Ce, O and Au elements can be seen in the overall spectrum. The above results all indicate that the cerium oxide-gold nanocatalytic material was successfully synthesized and has a small size.

[0080] (3) Ce 3+ Content and oxygen vacancy analysis

[0081] The valence states and surface chemical compositions of the ceria and ceria-gold nanocatalytic materials were measured using X-ray photoelectron spectroscopy (XPS) with an Al Ka ​​source. The C1s binding energy of 284.7 eV was used to calibrate other elements, enabling estimation of elemental valence state content.

[0082] XPS was used to characterize the near-surface area of ​​cerium oxide-gold nanocatalytic material particles, and high-resolution spectra of Ce 3d, O 1s and Au 4f photoelectrons were recorded. As can be seen in Table 2, after the addition of nano-gold particles, Ce 3+ The proportion of adsorbed oxygen (Os) increased significantly from 23.4% to more than 60%; the adsorbed oxygen content (Os) increased significantly from 39.1% to more than 57%. This shows that loading nano-gold on the surface of ceria can increase the unsaturated coordination of Ce. 3+ That is to say, the interaction between gold and ceria promotes the migration of electrons from gold to ceria, which is beneficial to the surface Ce 3+ The formation of oxygen vacancies leads to the increase of catalytic performance.

[0083] Table 2 Sample XPS composition information

[0084] sample Trivalent cerium content (%) Adsorbed oxygen content (%) Comparative Example 1 23.4 39.1 Example 1 66.7 60.4 Example 2 63.1 57.2 Example 3 60.5 57.1 Example 4 60.3 59.3

[0085] (4) Photoelectric performance experiment

[0086] The current density-voltage (IV) curve of the cerium oxide-gold nanocatalyst was measured using an electrochemical workstation, using sodium sulfate as the electrolyte. The working electrode was prepared as follows: 0.2 mL of Nafion (a perfluorosulfonic acid polymer) solution was added to 0.8 mL of anhydrous ethanol. 8 mg of ceria and the cerium oxide-gold nanocatalyst were ultrasonically dispersed in the solution. Finally, 100 μL of the mixed solution was dropped onto a conductive glass plate and allowed to dry naturally before measurement.

[0087] In order to illustrate the photoelectric properties of the materials, the photogenerated electron-hole pair separation and transfer performance of cerium dioxide and cerium oxide-gold nanocatalytic materials were tested by photocurrent response. Figure 4 The IV curves for ceria and ceria-gold nanocatalysts under visible light irradiation are shown below. Under visible light irradiation, as the applied bias increases, the photocurrent density of ceria rapidly approaches saturation and becomes increasingly lower than that of the composite material. The ceria-gold nanocatalyst exhibits a higher photocurrent density. This indicates that the ceria-gold nanocatalyst exhibits stronger photoelectric performance and the best photocatalytic performance under visible light compared to the other samples.

[0088] (5) Antibacterial test

[0089] In the inhibition zone test, firstly the concentration of 10 7 A bacterial suspension (100 μg / mL) was mixed with a nutrient solution and solidified into a test plate. The cerium oxide-gold nanocatalytic material was then placed in a 10 mm mold, compacted, and placed in the center of the plate for incubation at a constant temperature. The diameter of the inhibition zone was measured and calculated using the formula W = (TD) / 2 (where W is the width of the inhibition zone, T is the total diameter, and D is the sample diameter) to evaluate the antibacterial performance of the photocatalytic material.

[0090] Table 3 shows a comparison of the width of the bacterial inhibition ring of different photocatalytic materials under visible light irradiation. It can be seen from Table 3 that the width of the inhibition ring of the cerium oxide-gold nanocatalytic material is significantly larger than that of pure cerium dioxide, indicating that the cerium oxide-gold nanocatalytic material exhibits strong antibacterial properties under visible light irradiation.

[0091] Table 3 Antibacterial performance of samples

[0092] sample Total diameter (mm) Inhibition ring width (mm) Comparative Example 1 13.56 1.78 Example 1 22.84 6.42 Example 2 22.76 6.38 Example 3 22.70 6.35 Example 4 22.82 6.41

[0093] (6) Catalytic experiment

[0094] Equal weights of ceria and ceria-gold nanocatalytic material were evenly placed in a watch glass, which was then placed in a glass reactor. A 37% formaldehyde solution was slowly injected into the glass reactor, and a visible light source was turned on. The reaction was allowed to proceed for 4 hours, and the formaldehyde concentration was monitored using a multi-component gas analyzer.

[0095] Table 4 shows the performance of the photocatalytic material in removing formaldehyde under visible light. As can be seen from Table 4, the formaldehyde concentration of the cerium oxide-gold nanocatalytic material continued to decrease after 4 hours, while the carbon dioxide concentration increased. This indicates that formaldehyde was oxidized into carbon dioxide and water under the action of the cerium oxide-gold nanocatalytic material, and the catalytic performance of the photocatalytic material for formaldehyde under visible light was significantly improved.

[0096] Table 4 Catalytic activity of samples

[0097]

[0098]

[0099] In the description of this application, the descriptions with reference to the terms "in one embodiment", "in some embodiments", "in other embodiments", "in yet other embodiments", or "exemplary" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine different embodiments or examples described in this application and features of different embodiments or examples, unless they are mutually inconsistent.

[0100] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application are intended to be within the scope of protection of the present application.

Claims

1. A method for preparing a cerium oxide-gold nanocatalytic material, characterized in that: The following steps are involved: S01, adding a weak acid and a strong base weak acid salt to deionized water, stirring evenly to obtain a buffer solution; S02, adding the cerium source and the gold source to the buffer solution, and stirring to form a mixed solution; S03, after subjecting the mixed solution to a photoreduction reaction, transferring the mixed solution to a hydrothermal reaction vessel for a hydrothermal reaction to obtain a cerium oxide-gold mixture; S04, after the cerium oxide-gold mixture is cooled to room temperature, centrifuging to obtain a precipitate; S05. Wash the precipitate with deionized water several times and then dry it to obtain a cerium oxide-gold nanocatalytic material; wherein the cerium oxide-gold nanocatalytic material includes cerium dioxide and nano-gold supported on the surface of the cerium dioxide, the cerium dioxide and the nano-gold are both spherical or quasi-spherical, and the particle size of the cerium dioxide and the particle size of the nano-gold are both 3nm-15nm.

2. The preparation method according to claim 1, characterized in that The weak acid is one or a combination of at least two of acetic acid, glacial acetic acid, and citric acid; and / or The strong base and weak acid salt is one or a combination of sodium acetate and sodium citrate.

3. The preparation method according to claim 1 or 2, characterized in that The pH value of the buffer solution is 4-6.

4. The preparation method according to claim 1 or 2, characterized in that The stirring time in step S01 is 5 min-20 min.

5. The preparation method according to claim 1 or 2, characterized in that The cerium source is one or a combination of at least two of ammonium cerium nitrate, cerium acetate, and cerium chloride heptahydrate; and / or, The gold source is one of chloroauric acid and gold acetate, or a combination of the two.

6. The preparation method according to claim 1 or 2, characterized in that The photoreduction reaction is carried out by irradiating a xenon lamp for 10 minutes to 30 minutes.

7. The preparation method according to claim 1 or 2, characterized in that The temperature of the hydrothermal reaction is 150° C.-250° C., and the reaction time is 12 h-24 h.

8. The preparation method according to claim 1 or 2, characterized in that The drying temperature in step S01 is 30° C.-80° C., and the drying time is 4 h-15 h.

9. A cerium oxide-gold nanocatalytic material, characterized in that: The cerium oxide-gold nanocatalytic material is prepared by the preparation method according to any one of claims 1 to 8.

10. The cerium oxide-gold nanocatalytic material according to claim 9, characterized in that: The particle size of the cerium dioxide is 3nm-10nm.

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