A noble metal-inlaid mesoporous cerium dioxide hollow sphere composite material, its preparation method and application

Abstract

This invention relates to the field of catalytic material preparation technology, providing a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material, its preparation method, and its applications. The preparation method includes adding an organic acid, an alcoholic organic solvent, a cerium salt, and a noble metal salt to a pure aqueous solution, stirring thoroughly to form a reaction solution; allowing the stirred reaction solution to stand at 150–200°C; washing the solution after standing, and then drying the precipitate; calcining the dried product at 200–300°C. This invention enables the embedding of noble metal nanoparticles into the shell of a cerium dioxide hollow material, effectively inhibiting the migration, aggregation, and deactivation of noble metal nanoparticles in catalytic reactions, resulting in a highly active catalyst material suitable for the catalytic oxidation and degradation of VOCs.

Description

Technical Field

[0001] This invention belongs to the field of catalytic materials technology, specifically relating to a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material, its preparation method, and its application. Background Technology

[0002] Noble metal-based catalysts have a wide range of applications in catalysis. Platinum (Pt) is a common example among noble metal-based catalysts, and it has been extensively studied in various catalytic reactions, such as VOCs degradation, automotive exhaust purification, selective hydrogenation, and organic catalytic reactions, especially in the catalytic oxidation of VOCs. However, the preparation of noble metal catalysts presents challenges. For example, Pt nanoparticles tend to migrate and aggregate into larger particles during formation, thus minimizing their surface free energy. Furthermore, the unavoidable calcination process during the preparation of supported Pt nanoparticles can affect their catalytic performance, even causing complete deactivation.

[0003] CeO2 is one of the most abundant rare earth oxides on Earth. Its abundant oxygen vacancy defects, high oxygen storage capacity, and flexible conversion between Ce(IV) and Ce(III) can significantly improve the reaction rate of redox steps. Current technologies have enabled the preparation of CeO2 with nanosphere, nanorod, nanoparticle, and nanocube structures, and these materials exhibit significant shape-dependent behavior. When noble metals are combined with cerium dioxide, Ce's unique electronic configuration and structural properties promise to make noble metal-CeO2 materials highly efficient VOC catalysts.

[0004] Currently, the preparation of noble metal-CeO2 materials often employs a metal impregnation method. This involves first preparing cerium dioxide, then using it as a carrier to impregnate a metal precursor solution onto the cerium dioxide, thus loading the metal onto the cerium dioxide. Subsequent calcination yields the noble metal-CeO2 material. However, this method merely loads noble metal nanoparticles onto the CeO2 carrier surface. These nanoparticles can still migrate, grow, and aggregate into larger particles, failing to exert a synergistic effect with CeO2. Furthermore, the calcination step in this supported preparation method can affect the catalytic performance of the catalyst, even causing complete deactivation. Summary of the Invention

[0005] This invention provides a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material, which can embed noble metal nanoparticles into the shell of cerium dioxide hollow material, effectively inhibiting the migration, aggregation and deactivation of noble metal nanoparticles in catalytic reactions, and obtaining a highly active catalyst material that can be used for the catalytic oxidation and degradation of VOCs.

[0006] In a first aspect, the present invention provides a method for preparing a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material, comprising the following steps:

[0007] (1) Pre-prepared reaction solution: Cerium salt is added to pure water and stirred to dissolve. Then organic acid and alcohol organic solvent are added to it and stirred. After stirring, noble metal salt is added and stirred to form a reaction solution.

[0008] (2) Static reaction: The reaction solution after stirring in step (1) is allowed to stand for reaction at a temperature of 150-200℃.

[0009] (3) Wash the solution after the reaction in step (2) and then dry the precipitate;

[0010] (4) Calcination: Take the dried product from step (3) and calcine it at a temperature of 200-300℃.

[0011] Optionally, the organic acid includes one or more of formic acid, acetic acid, or propionic acid; the alcoholic organic solvent includes one or more of methanol, ethylene glycol, or glycerol; the cerium salt includes one or more of cerium chloride, cerium nitrate, or cerium sulfate; and the noble metal element in the noble metal salt includes one or more of platinum, palladium, ruthenium, or iridium.

[0012] Optionally, the noble metal element of the noble metal salt is platinum, and the noble metal salt includes any one or more of platinum acetylacetonate, potassium chloroplatinate, and platinum chloride.

[0013] Optionally, the organic acid is acetic acid, the alcoholic organic solvent is ethylene glycol, the cerium salt is cerium nitrate hexahydrate, and the noble metal salt is potassium chloroplatinate.

[0014] Optionally, the potassium chloroplatinate in the reaction solution has a mass fraction of 0.5–4.0 wt%.

[0015] Optionally, the ratio of cerium nitrate hexahydrate to pure water is 1:1 (w / v); the molar ratio of cerium nitrate hexahydrate, acetic acid, and ethylene glycol in the reaction solution is (0.3-0.7):(2.5-10.0):(70-90).

[0016] Optionally, the ratio of the amount of pure water, acetic acid, ethylene glycol and cerium nitrate hexahydrate added in step (1) is (1.0-2.0 mL): (1.0-2.0 mL): (30.0-60.0 mL): (1.0-2.0 g).

[0017] Optionally, step (2) includes: transferring the reaction solution into a polytetrafluoroethylene-lined reactor and placing it in the reactor for static reaction; the reaction time of the static reaction is 2 to 5 hours.

[0018] Optionally, in step (3), the washing process involves alternating centrifugation with ultrapure water and anhydrous ethanol for 6 to 8 times.

[0019] Optionally, in step (4), the calcination is carried out in a muffle furnace for 4 to 6 hours.

[0020] In a second aspect, the present invention provides a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material prepared by the above-described preparation method.

[0021] A third aspect of the present invention provides the application of the above-described noble metal-inlaid mesoporous cerium dioxide hollow sphere composite material in the catalytic oxidation of VOCs.

[0022] Optionally, the catalytic oxidation reaction temperature of VOCs is below 300℃.

[0023] Optionally, the VOCs include benzene, toluene, and xylene.

[0024] Compared to conventional supported noble metal-based mesoporous cerium dioxide spherical materials, this invention presents a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material prepared by a one-pot hydrothermal method. In this composite material, the noble metal nanoparticles are successfully embedded within the shell of the mesoporous cerium dioxide hollow spheres, rather than being loaded onto the surface of the cerium dioxide spheres. Furthermore, the preparation method of this invention employs low-temperature calcination, which avoids material deactivation caused by the agglomeration of metal particles.

[0025] More specifically, the composite material of the present invention can enhance catalytic activity through the synergistic effect between highly dispersed metal nanoparticles and surrounding self-assembled mesoporous cerium dioxide nanoparticles. The relatively uniformly distributed metal nanoparticles in the self-assembled mesoporous cerium dioxide nanoparticles can form a porous nanostructure, thereby helping to generate a large number of active sites, making it easier for spatially confined volatile organic compound (VOC) molecules to enter the active sites and promote the oxidation process.

[0026] Furthermore, the composite material of the present invention has a large specific surface area and a hollow structure, which enables reactant molecules to diffuse easily and products to transfer quickly, thereby facilitating the reaction. It can also effectively prevent structural damage in subsequent VOCs catalytic oxidation reactions and avoid excessive oxidation of noble metal active sites. Attached Figure Description

[0027] Figure 1 The image shows the XRD pattern of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared in Example 1.

[0028] Figure 2 The image shows a (HR)TEM image of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared in Example 1.

[0029] Figure 3 Another (HR) TEM image of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared in Example 1;

[0030] Figure 4 The graph shows the toluene catalytic oxidation performance of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared in Example 1.

[0031] Figure 5 The image shows the XRD pattern of the supported platinum-based mesoporous cerium dioxide spherical material prepared in Comparative Example 1.

[0032] Figure 6 (HR)TEM image of the supported platinum-based mesoporous cerium dioxide spherical material prepared in Comparative Example 1;

[0033] Figure 7 The figure shows the toluene catalytic oxidation performance of the supported platinum-based mesoporous cerium dioxide spherical material prepared in Comparative Example 1. Detailed Implementation

[0034] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0035] This invention provides a method for preparing a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material, comprising the following steps:

[0036] (1) Pre-prepared reaction solution: Cerium salt is added to pure water and stirred to dissolve. Then organic acid and alcohol organic solvent are added to it and stirred. After stirring, noble metal salt is added and stirred to form a reaction solution.

[0037] (2) Static reaction: The reaction solution after stirring in step (1) is allowed to stand for reaction; the reaction temperature is 150-200℃.

[0038] (3) Wash the solution after the reaction in step (2) and then dry the precipitate;

[0039] (4) Calcination: Take the dried product from step (3) and calcine it at a temperature of 200-300℃.

[0040] This invention embeds small nanoparticles into the shell of a porous CeO2 hollow structure to obtain a high-performance catalyst.

[0041] Specifically, the noble metals include elements such as platinum, palladium, ruthenium, and iridium. Because their d-electron orbitals are not fully filled, noble metals readily adsorb reactants on their surfaces, exhibit diverse coordination, and demonstrate strong selectivity in catalytic reactions. Furthermore, they possess moderate adsorption strength for reactants and intermediates, facilitating the formation of intermediate active species and exhibiting high catalytic activity. Moreover, noble metals generally possess stable chemical properties, allowing them to withstand more demanding catalytic environments, thus offering significant advantages. This invention, through the aforementioned preparation method, uses mesoporous hollow cerium dioxide spheres as a carrier and embeds noble metal particles within the hollow spheres. This process suppresses the active centers of the metal nanoparticles within the carrier, preventing particle migration and the corresponding decrease in catalytic activity.

[0042] The preparation method of this invention is simple and efficient, and can effectively control the position and uniformity of the supported metal nanoparticles in a short time, thereby effectively enhancing catalytic activity. Simultaneously, the hollow structure of the mesoporous CeO2 hollow spheres provides a high surface area, internal void space, and open porous channels, which is beneficial for more uniform dispersion of the noble metal nanoparticles. Embedding metal nanoparticles into the shell of a hollow material to prepare a noble metal embedded composite material can maximize the interaction between the metal nanoparticles and the support, thereby effectively inhibiting the migration, aggregation, and deactivation of metal nanoparticles in the catalytic reaction, ultimately contributing to improved catalytic activity.

[0043] In specific implementations, the organic acid includes one or more of formic acid, acetic acid, or propionic acid; the alcoholic organic solvent includes one or more of methanol, ethylene glycol, or glycerol; the cerium salt includes one or more of cerium chloride, cerium nitrate, or cerium sulfate; and the noble metal element in the noble metal salt includes one or more of platinum, palladium, ruthenium, or iridium.

[0044] Furthermore, and crucially, this invention employs a low-temperature calcination method, with calcination temperatures below 300°C. This calcination temperature allows for finer grain sizes, enabling the successful integration of noble metal nanoparticles into the mesoporous cerium dioxide hollow sphere support. It also prevents metal particle agglomeration, thus avoiding material deactivation. The lower calcination temperature also prevents the calcination process from affecting the catalyst's catalytic performance, preventing catalyst deactivation. Moreover, the composite catalytic material prepared by this invention can achieve complete oxidation of VOCs such as toluene at temperatures below 300°C. Since the calcination temperature during material preparation is higher than the catalytic oxidation reaction temperature during application, the material maintains stability during the catalytic oxidation reaction, avoiding damage to the structure and performance of the catalytic material caused by high catalytic reaction temperatures.

[0045] In a more specific embodiment, the noble metal element of the noble metal salt is platinum, and the noble metal salt includes any one or more of platinum acetylacetonate, potassium chloroplatinate, and platinum chloride.

[0046] A more specific embodiment is that the organic acid is acetic acid, the alcoholic organic solvent is ethylene glycol, the cerium salt is cerium nitrate hexahydrate, and the noble metal salt is potassium chloroplatinate.

[0047] For the specific reagent selection mentioned above, the dosage in step (1) during preparation has a more preferred range. The mass fraction of potassium chloroplatinate in the reaction solution is 0.5–4.0 wt%. For the dosage of other reagents, one method is that the ratio of cerium nitrate hexahydrate to pure water is 1:1 (w / v), and the molar ratio of acetic acid, ethylene glycol, and cerium nitrate hexahydrate in the reaction solution is (2.5–10.0):(70–90):(0.3–0.7), or more preferably (2.7–9.6):(74.4–87.7):(0.4–0.6); another method is that the ratio of pure water, acetic acid, ethylene glycol, and cerium nitrate hexahydrate is (1.0–2.0 mL):(1.0–2.0 mL):(30.0–60.0 mL):(1.0–2.0 g).

[0048] Aside from the dosage of the reagent, some preferred embodiments of other preparation steps are as follows.

[0049] Specifically, step (2) includes: transferring the reaction solution into a polytetrafluoroethylene-lined reactor and placing it in the reactor for static reaction; the reaction time is 3 hours. This step is a hydrothermal reaction.

[0050] In step (3), the washing process involves alternating centrifugation with ultrapure water and anhydrous ethanol for 6 to 8 times.

[0051] In step (4), the calcination is carried out in a muffle furnace for 4 hours.

[0052] Based on the above scheme, a method for preparing a platinum-embedded mesoporous cerium dioxide hollow sphere composite material includes the following steps:

[0053] 1) Pre-prepared reaction solution: Cerium nitrate hexahydrate is added to pure water and stirred to dissolve. Then acetic acid and ethylene glycol are added and stirred. Potassium chloroplatinate is added and stirred to form the reaction solution.

[0054] 2) Static reaction: The reaction solution after stirring in step (1) is allowed to stand for reaction; the reaction temperature for static reaction is 150-200℃;

[0055] 3) After washing the solution from step (2), take the precipitate and dry it;

[0056] 4) Calcination: Take the dried product from step (3) and calcine it at a temperature of 200-300℃ to obtain the platinum-embedded mesoporous cerium dioxide hollow sphere composite material.

[0057] Based on the above scheme, the present invention also provides a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material prepared by the above preparation method.

[0058] The composite material obtained by this invention can be used as a catalyst for the catalytic oxidation of VOCs (volatile organic compounds), such as benzene, toluene, and xylene. The catalytic oxidation reaction temperature can be low, more specifically, below 200°C, below 300°C, or below the calcination temperature during catalyst preparation.

[0059] In this invention, the relatively uniformly distributed metal nanoparticles in the self-assembled mesoporous cerium dioxide nanoparticles can form a porous nanostructure, which helps to generate a large number of active sites, making it easier for spatially confined VOCs molecules to enter the active sites and promote their oxidation process.

[0060] Compared with supported noble metal-based mesoporous cerium dioxide spherical materials, the noble metal-embedded mesoporous cerium dioxide hollow sphere composite material prepared by the one-pot hydrothermal method of the present invention has a larger specific surface area and a hollow structure, which not only makes it easier for reactant molecules to diffuse and products to transfer quickly, thus facilitating the reaction, but also effectively prevents structural damage and excessive oxidation of metal active sites in subsequent VOCs oxidation reactions.

[0061] Example 1

[0062] A simple one-pot hydrothermal method according to the present invention was used to prepare a platinum-embedded mesoporous cerium dioxide hollow sphere composite material. First, 1.0 g of cerium nitrate hexahydrate was added to a beaker containing 1.0 mL of ultrapure water under stirring, allowing the cerium nitrate hexahydrate to fully dissolve in the ultrapure water to form a clear solution. Then, under stirring, 1.0 mL of acetic acid solution and 30.0 mL of ethylene glycol solution were added sequentially, and the mixture was stirred for 30 min. After stirring, potassium chloroplatinate was added to the homogenized solution to achieve a mass fraction of 1.0 wt%, and the mixture was stirred vigorously for another 30 min. The stirred solution was placed in a reaction vessel, sealed, and placed in a preheated oven at 180°C, where it was kept at a constant temperature for 150 min. After the hydrothermal reaction, the reaction vessel was removed and allowed to cool naturally to room temperature. The supernatant was removed by centrifugation to obtain the precipitate, which was then centrifuged repeatedly with alternating ultrapure water and anhydrous ethanol solutions to remove residual solvent. Finally, the product was dried in an oven at 60°C for 12 h. Finally, the dried solid sample was placed in a muffle furnace and calcined at 300°C for 4 hours. The final product was a platinum-embedded mesoporous cerium dioxide hollow sphere composite material.

[0063] The materials prepared in Example 1 were analyzed using XRD characterization. Figure 1As can be seen, the prepared material exhibits six distinct XRD characteristic diffraction peaks near 28.6°, 33.0°, 47.4°, 56.4°, 69.8°, and 77.2°. These diffraction peaks are consistent with the cubic fluorite CeO2 structure, representing the (1 1 1), (2 0 0), (2 2 0), (31 1), (4 0 0), and (3 3 1) crystal planes, respectively. This indicates the presence of a cubic fluorite CeO2 structure (PDF#34-0394) in the material. Furthermore, XRD diffraction peaks of the (1 1 1) crystal plane of the face-centered cubic Pt nanoparticle structure (PDF#04-0802) were also observed. Therefore, it is proven that Pt in the material can be successfully reduced.

[0064] Figure 2 and Figure 3 This is a high-resolution (HR) TEM image of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared by the one-pot hydrothermal method of this invention. As can be seen from the image, the surface of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material is rough, revealing a three-dimensional interconnected porous structure composed of self-assembled CeO2 nanoparticles. Furthermore, the hollow structure of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material consists of Pt nanoparticles (Pt nanoparticles) surrounded by self-assembled CeO2 nanoparticles. Figure 3 (As indicated by the middle arrow), they can be distinguished by their contrast with the bright interior. This indicates that the platinum-embedded mesoporous cerium dioxide hollow sphere composite material is formed by a self-assembly-reduction-Ostwald curing process, in which Pt nanoparticles are successfully embedded into the mesoporous hollow spheres.

[0065] The prepared platinum-embedded mesoporous cerium dioxide hollow sphere composite material (i.e., catalyst) was used to conduct experiments on the catalytic oxidation of toluene. The reaction conditions were as follows: 200 mg of catalyst sample was weighed and placed in the center of a quartz tube (id = 8.00 mm) in a tubular furnace. Toluene gas was generated in a gas generator at a vaporization temperature of 110 °C. At a total continuous flow rate of 100 mL / min, the volume composition of the reactant gas mixture was syngas containing 1000 ppm toluene (20 vol.% O2, N2 equilibrium), corresponding to a gas hourly space velocity (GHSV) of 30000 mL / (g·h). The generated gases were analyzed online using a GC-7900 gas chromatograph (Techcomp, Shanghai) equipped with a thermal conductivity detector (TCD) and a flame ionization detector (FID).

[0066] Figure 4The figure shows the toluene conversion rate of the platinum-embedded mesoporous cerium dioxide hollow sphere composite material under different reaction temperature conditions. It is clear from the figure that the platinum-embedded mesoporous cerium dioxide hollow sphere composite material can completely oxidize toluene at a reaction temperature of 180℃, achieving a 100% toluene conversion rate. This demonstrates that the catalytic material can completely oxidize toluene at relatively low reaction temperatures (below 200℃), indicating that the platinum-embedded mesoporous cerium dioxide hollow sphere composite material synthesized in this invention can be directly used as a catalyst and possesses excellent catalytic performance.

[0067] Example 2

[0068] In Example 1, the amount of potassium chloroplatinate added was varied to achieve a mass fraction of 2 wt% in the reaction solution, followed by vigorous stirring for 30 min. The stirred solution was then placed in a reaction vessel, sealed, and placed in a preheated 180°C oven, where it was kept at a constant temperature for 150 min. After the hydrothermal reaction, the sample was centrifuged and washed to remove residual solvent. It was then dried in an oven at 60°C for 12 h. Finally, the dried solid sample was placed in a muffle furnace and calcined at 260°C for 4 h. The final product was a platinum-embedded mesoporous cerium dioxide hollow sphere composite material.

[0069] The platinum-embedded mesoporous cerium dioxide hollow sphere composite material prepared in Example 2 can completely oxidize toluene at a reaction temperature of 240°C, achieving a 100% toluene conversion rate.

[0070] Comparative Example 1

[0071] For comparison, this comparative example prepared a supported platinum-based mesoporous cerium dioxide spherical catalyst with a platinum loading of 1.0 wt.% using an equal-volume impregnation method, wherein potassium chloroplatinate was the precursor of metallic platinum. Specifically, firstly, 1.0 g of cerium nitrate hexahydrate was added to a beaker containing 1.0 mL of ultrapure water under stirring, and the cerium nitrate hexahydrate was allowed to fully dissolve in the ultrapure water to form a clear solution. Then, 1.0 mL of acetic acid solution and 30.0 mL of ethylene glycol solution were added sequentially under stirring for 30 min. The homogenized mixture was transferred to a high-pressure reactor with a polytetrafluoroethylene liner. It was placed in a forced-air oven preheated to 180 °C and kept at a constant temperature for 150 min. After the hydrothermal reaction, the reactor was removed and allowed to cool naturally to room temperature. The supernatant was removed by centrifugation to obtain the precipitate, which was then centrifuged repeatedly with ultrapure water and anhydrous ethanol solution to remove residual solvent. Finally, it was dried in an oven at 60 °C for 12 h. Finally, the dried solid sample was calcined in a muffle furnace (500℃, 4h). The resulting product was mesoporous cerium dioxide spherical material.

[0072] First, weigh 1.0 wt% potassium chloroplatinate and place it in a screw-top bottle, then add an appropriate amount of ultrapure water to dissolve it completely. Next, add the potassium chloroplatinate solution dropwise onto the mesoporous cerium dioxide spherical support, while continuously stirring with a spatula to ensure the potassium chloroplatinate is fully dispersed on the support. After impregnation, dry the catalyst precursor in an oven at 60°C for 12 hours, then place the dried sample in a muffle furnace and calcine it at 300°C for 4 hours. Finally, a supported platinum-based mesoporous cerium dioxide spherical material is obtained.

[0073] The supported platinum-based mesoporous cerium dioxide spherical material prepared by the impregnation method in Comparative Example 1 was characterized and analyzed. Figure 5 The XRD characterization diagram shows that the material exhibits the characteristic XRD diffraction peaks of the three-dimensional fluorite structure CeO2 (PDF#34-0394) and metallic Pt nanoparticles. Figure 6 This is a high-resolution (HR) TEM image of the supported platinum-based mesoporous cerium dioxide spherical material in this comparative example. The image shows that the material exhibits a uniformly sized spherical morphology with an average particle size of 140 nm. It can also be clearly seen that each nanosphere is composed of many single-crystal grains. Furthermore, Pt is uniformly distributed on the material surface, indicating that metallic Pt particles were loaded onto the surface of the mesoporous cerium dioxide spherical material via an impregnation method.

[0074] The prepared supported platinum-based mesoporous cerium dioxide spherical material was subjected to a toluene-catalyzed oxidation reaction. The experimental method and reaction conditions were the same as in Example 1. Figure 7 The figure shows the toluene conversion rate of the supported platinum-based mesoporous cerium dioxide spherical material under different reaction temperatures. It is clear from the figure that the supported platinum-based mesoporous cerium dioxide spherical material achieves 100% toluene conversion only at a reaction temperature of 360℃. Compared with the platinum-embedded mesoporous cerium dioxide hollow sphere composite material obtained in Example 1, it exhibits poorer toluene catalytic oxidation performance.

[0075] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention.

Claims

1. The application of a noble metal-embedded mesoporous cerium dioxide hollow sphere composite material in the catalytic oxidation of VOCs, characterized in that, The preparation method of the noble metal-embedded mesoporous cerium dioxide hollow sphere composite material includes the following steps: (1) Pre-prepared reaction solution: Cerium salt is added to pure water and stirred to dissolve. Then organic acid and alcohol organic solvent are added to it and stirred. After stirring, noble metal salt is added and stirred to form reaction solution; (2) Static reaction: The reaction solution after stirring in step (1) is allowed to stand for reaction at a temperature of 150~200℃. (3) Wash the solution after the reaction in step (2) and then dry the precipitate; (4) Calcination: Take the dried product from step (3) and calcine it at a temperature of 200~300℃; The organic acid is acetic acid, the alcohol organic solvent is ethylene glycol, the cerium salt is cerium nitrate hexahydrate, and the noble metal salt is potassium chloroplatinate; in step (1), the mass fraction of potassium chloroplatinate in the reaction solution is 1 wt%.

2. The application according to claim 1, characterized in that, The ratio of cerium nitrate hexahydrate to pure water is 1:1 (w / v); the molar ratio of cerium nitrate hexahydrate, acetic acid, and ethylene glycol in the reaction solution is (0.3~0.7):(2.5~10.0):(70~90).

3. The application according to claim 1, characterized in that, The ratio of the added pure water, acetic acid, ethylene glycol, and cerium nitrate hexahydrate is (1.0~2.0mL):(1.0~2.0mL):(30.0~60.0mL):(1.0~2.0g).

4. The application according to claim 1, characterized in that, Step (2) includes: transferring the reaction solution to a polytetrafluoroethylene-lined reactor and placing it in the reactor for static reaction; the reaction time of the static reaction is 2 to 5 hours; in step (4), the calcination is carried out in a muffle furnace for 4 to 6 hours.

5. The application according to claim 1, characterized in that, In step (3), the washing process involves alternating centrifugation with ultrapure water and anhydrous ethanol for 6 to 8 times.

6. The application according to claim 5, characterized in that, The catalytic oxidation reaction temperature of VOCs is below 300℃; VOCs include benzene, toluene, and xylene.

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