Catalyst for complete oxidation of benzene and method for preparing the same, and method for complete oxidation of benzene

Abstract

The present application relates to the technical field of molecular sieve preparation, and provides a preparation method of a catalyst for benzene complete oxidation reaction.The preparation method comprises the following steps: mixing SBA molecular sieve raw powder, a metal source, a first silicon source and an alkali solution to obtain a mixture, and then performing molding and drying on the mixture to obtain molecular sieve A; wherein the metal source comprises at least one of a gold source, a platinum source and a palladium source; mixing an organic template agent R, water, a second silicon source and an acid to obtain solution B; adding solution B into the molecular sieve A, and then performing hydrothermal crystallization, filtration, washing, drying and calcination to obtain the catalyst for benzene complete oxidation reaction.The preparation method is simple, and the catalyst prepared by the method is covered with a silicon dioxide film outside the molecular sieve, so that the metal active sites are not easy to be lost in the reaction process.The present application further provides a catalyst for benzene complete oxidation reaction and a benzene complete oxidation reaction method.

Description

Technical Field

[0001] The present invention relates to the technical field of molecular sieve preparation, and more particularly to a catalyst for benzene complete oxidation reaction and a preparation method thereof, as well as a benzene complete oxidation reaction method. Background Art

[0002] SBA-15 and SBA-16 are both typical mesoporous molecular sieves, characterized by large specific surface area, adjustable pore size, and excellent hydrothermal stability. These properties not only increase contact between the catalyst and reactants, promoting reactions, but also enhance mass and heat transfer performance. Therefore, they are often used as catalyst supports in the preparation of noble metal (Pt, Rh, Pd, Au, etc.)-supported catalysts. These noble metal-supported catalysts are commonly used as heterogeneous catalysts not only in hydrogenation and dehydrogenation reactions, but also in selective reduction and complete oxidation of small gases (CO, methane, etc.) and volatile organic compounds (VOCs). Examples include hydrogenation of benzene, toluene, and cyclohexene, dehydrogenation of propane, selective catalytic reduction (SCR) of NOx, oxidation of CO, methane combustion, and complete oxidative decomposition of typical VOCs such as benzene, toluene, and n-hexane. They are also used in oxidation reactions of certain polycyclic aromatic hydrocarbons.

[0003] The catalyst preparation method has a great influence on the properties of precious metal supported catalysts. Since precious metals are expensive, their dosage is usually reduced as much as possible during the catalyst preparation process, while maintaining the stability of the catalyst and extending the service life of the catalyst as much as possible, thereby achieving the purpose of reducing the catalyst cost. One of the strategies for catalyst preparation is usually to achieve high dispersion of precious metals on the surface of the carrier as much as possible during the preparation process, thereby enhancing the catalytic efficiency of the precious metals, while reducing the loss of precious metals during the reaction process, thereby extending the service life of the catalyst. However, the metal components in existing supported catalysts are dispersed on the surface of the molecular sieve, which easily causes the loss of metal components during the reaction process. Therefore, there are technical problems such as shortened catalyst service life and reduced catalytic effect. Summary of the Invention

[0004] In order to solve the above technical problems, one of the objects of the present invention is to provide a method for preparing a catalyst for the complete oxidation reaction of benzene. During the kneading process of the catalyst, a raw material silicon source used for synthesizing molecular sieves is added, and then the silicon source is hydrolyzed into viscous silica gel to bond the catalyst. At the same time, the secondary pore distribution of the molecular sieve is improved in this process.

[0005] The present invention also aims to provide a catalyst for the complete oxidation of benzene and a method for the complete oxidation of benzene.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present application provides a preparation method of a catalyst for complete oxidation of benzene, comprising:

[0008] S1. mixing SBA molecular sieve raw powder, a metal source, a first silicon source and an alkali solution to obtain a mixture, and subjecting the mixture to molding, drying to obtain a molecular sieve A; wherein the metal source comprises at least one of a gold source, a platinum source and a palladium source;

[0009] S2. mixing an organic template agent R, water, a second silicon source and an acid to obtain a solution B;

[0010] S3. adding the solution B into the molecular sieve A, subjecting to hydrothermal crystallization, filtering, washing, drying and calcining to obtain a catalyst for complete oxidation of benzene.

[0011] In the preparation method of the catalyst for complete oxidation of benzene, the first silicon source is hydrolyzed under the action of the alkali solution to generate a sticky silica gel network, and the sticky silica gel network bonds the molecular sieve particles to each other. After extrusion molding, the sticky silica gel network is converted into a silica film under the condition of high-temperature calcination, which covers the silicon hydroxyl structure on the outer surface of the molecular sieve. Due to the silica film and the skeleton structure of the molecular sieve itself, the silica film does not cover and block the outer surface of the molecular sieve. In actual application, the reactants can enter the outer surface of the molecular sieve from the silica film in the form of diffusion. However, due to the distribution of the metal on the outer surface of the molecular sieve, the silica film formed at the position of the metal has a gap. The gap position is subjected to crystallization growth by adding a mixed solution of the organic template agent R, water, the second silicon source and the acid to perform hydrothermal crystallization, so as to form a complete silica film on the outer surface of the molecular sieve. The silica film can improve the mechanical strength of the molecular sieve and provide a protective film for the structure of the molecular sieve itself. The protective film does not affect the activity and diffusion performance of the molecular sieve itself due to the similar silica structure of the skeleton structure of the molecular sieve, and can also prevent the metal active site from being lost in the reaction process, effectively prolonging the service life and activity of the catalyst. In addition, the silica film formed on the outer surface of the molecular sieve can effectively avoid the problem of catalyst deactivation caused by the agglomeration of metal particles at high temperature.

[0012] According to some embodiments of the present application, the gold source comprises one or more of oxides, hydroxides, sulfides, chlorides and cyanides of gold; and / or the platinum source comprises one or more of oxides, hydroxides, sulfides, chlorides and cyanides of platinum; and / or the palladium source comprises one or more of oxides, hydroxides, sulfides, chlorides and cyanides of palladium.

[0013] According to some embodiments of the present application, the SBA molecular sieve crude powder comprises SBA-15 molecular sieve crude powder or SBA-16 molecular sieve crude powder.

[0014] According to some embodiments of the present application, the first silicon source comprises at least one of tetraethyl orthosilicate (TEOS), silica sol, water glass, preferably tetraethyl orthosilicate.

[0015] According to some embodiments of the present application, the alkali in the alkali solution comprises NaOH.

[0016] According to some embodiments of the present application, the organic template R comprises at least one of amphiphilic non-ionic triblock surfactant and hexamethylenetetramine (HMTA).

[0017] According to some embodiments of the present application, the amphiphilic non-ionic triblock surfactant comprises at least one of F127 (EO 106 PO 70 EO 106 ), F108 (EO 132 PO 50 EO 132 ), P123 (EO 20 PO 70 EO 20 ), P104 (EO 27 PO 61 EO 27 ).

[0018] According to some embodiments of the present application, when the SBA molecular sieve crude powder is SBA-15 molecular sieve crude powder, the organic template R is selected from one or more of P123 or P104; when the SBA molecular sieve crude powder is SBA-16 molecular sieve crude powder, the organic template R is selected from one or more of F127, F108 and HMTA.

[0019] According to some embodiments of the present application, the second silicon source comprises at least one of white carbon black, tetraethyl orthosilicate (TEOS), sodium silicate, silica sol, preferably tetraethyl orthosilicate.

[0020] According to some embodiments of the present application, the acid comprises at least one of hydrochloric acid, sulfuric acid, nitric acid, preferably hydrochloric acid.

[0021] According to some embodiments of the present application, the mass ratio of the metal source to the SBA molecular sieve crude powder is 1-10:100.

[0022] According to some embodiments of the present application, the mass ratio of the first silicon source to the SBA molecular sieve crude powder is 1:5-10.

[0023] According to some embodiments of the present application, the ratio of the ratio of the molar amount of the base in the alkali solution to the molar amount of the first silicon source calculated as SiO2 is 0.5-4:1. - According to some embodiments of the present application, the ratio of the ratio of the molar amount of the base in the alkali solution to the molar amount of the first silicon source calculated as SiO2 is 0.5-4:1.

[0024] According to some embodiments of the present application, the ratio of the ratio of the molar amount of the base in the alkali solution to the molar amount of the first silicon source calculated as SiO2 is 0.5-4:1. - According to some embodiments of the present application, the ratio of the ratio of the molar amount of the base in the alkali solution to the molar amount of the first silicon source calculated as SiO2 is 0.5-4:1.

[0025] According to some embodiments of the present application, the molar ratio of the components in the solution B is SiO2:a H2O:b R:c H + , wherein the value of a is 80-200, preferably 100-160, the value of b is 0.005-0.030, preferably 0.010-0.025, and the value of c is 0.10-0.25, preferably 0.15-0.20.

[0026] According to some embodiments of the present application, the mixture in step S1 is dried first, and then the dried mixture is mixed with water and shaped.

[0027] According to some embodiments of the present application, the mass of the water mixed with the dried mixture is 10%-30%, preferably 15%-25% of the mass of the dried mixture.

[0028] According to some embodiments of the present application, the drying temperature in step S1 is 100-140°C, preferably 110-130°C.

[0029] According to some embodiments of the present application, the crystallization temperature in step S3 is 80-130°C, preferably 90-120°C, and the crystallization time is 24-90h, preferably 40-70h.

[0030] According to some embodiments of the present application, the drying temperature in step S3 is 100-140°C, preferably 110-130°C.

[0031] According to some embodiments of the present application, the calcination temperature in step S3 is 400-700°C, preferably 500-600°C, and the calcination time is 5-8h.

[0032] In a second aspect, the present application provides a catalyst for complete oxidation of benzene, which is prepared by the method of the first aspect.

[0033] According to some embodiments of the present application, the surface of the catalyst for complete oxidation of benzene comprises a silica shell, and preferably the particle diameter of the catalyst for complete oxidation of benzene is 30-50nm.

[0034] In a third aspect, the present invention provides a method for the complete oxidation of benzene, wherein the catalyst is prepared by the preparation method described in the first aspect or is used to catalyze the reaction using the catalyst for the complete oxidation of benzene described in the second aspect.

[0035] The beneficial effects of the present invention are at least:

[0036] The present invention provides a simple method for preparing a catalyst for the complete oxidation of benzene. A metal source is directly added during the molecular sieve forming stage, eliminating the need for impregnation of the molecular sieve with a metal solution. The forming and metal impregnation processes are completed in a single step. The prepared metal-loaded SBA molecular sieve is coated with a silicon dioxide film, providing a protective layer for the molecular sieve structure. This prevents the loss of metal active sites during the reaction, effectively extending the catalyst's lifespan and activity. The catalyst can significantly improve benzene conversion in the complete oxidation reaction of benzene. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a scanning electron microscope image of the catalyst prepared in Example 3. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate this patent in detail and do not limit the scope of protection of the present invention in any way.

[0039] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following examples, etc., are all commercially available or can be obtained by existing methods; the reagent amounts used, unless otherwise specified, are the amounts used in conventional experimental procedures; and the experimental methods described, unless otherwise specified, are all conventional methods.

[0040] Among them, XPS uses Thermo's ESCALAB 250spectrometer X-ray photoelectron spectrometer to measure the bonding situation of metal particles.

[0041] The scanning electron microscope was a Hitachi S-4700 scanning electron microscope.

[0042] Example 1

[0043] S1. 40 g of SBA-16 molecular sieve powder, 0.8 g of Au2O, 4 g of tetraethyl orthosilicate (TEOS), and 0.3 L of 0.1 mol / L NaOH solution were mixed in a mortar and pestle. After uniform mixing, the mixture was dried at 100°C. Subsequently, 30 g of the dried sample was placed in an extruder, and 3 g of deionized water was added and stirred until uniformly mixed. Molding was then initiated. The formed molecular sieve was dried at 100°C and designated as molecular sieve A.

[0044] S2. 1.6 g of F127 and 34.5 g of deionized water were added to the reactor in sequence and stirred evenly. 24.1 mL of 0.1 mol / L hydrochloric acid solution was then added. Stirring was continued and 5 g of tetraethyl orthosilicate (TEOS) was slowly added dropwise to obtain solution B. The molar ratio of the components in solution B was SiO2: 80 H2O: 0.005 R: 0.1 H + .

[0045] S3. Solution B and molecular sieve A were mixed and transferred to a crystallization kettle. The temperature was raised to 90°C and crystallized at this constant temperature for 40 hours. After complete crystallization, the temperature was lowered to room temperature. The reaction mixture was separated, washed, and dried at 100°C. Finally, the catalyst sample was calcined at 400°C for 8 hours.

[0046] Example 2

[0047] S1. Add 40g of SBA-16 molecular sieve powder, 1.6g of AuCl3, 6g of silica sol (SW-25, silica content is 25wt%) and 0.3L of 0.1mol / L NaOH solution into a mortar and mix them. After mixing evenly, dry them at 100°C. Then take 30g of the dried sample and put it into an extruder. Add 6g of deionized water and stir evenly before starting to shape it. The formed molecular sieve is dried at 100°C and recorded as molecular sieve A.

[0048] S2. 4.4 g F108 and 54 g deionized water were added to the reactor in sequence, stirred evenly, and then 44.8 mL 0.1 mol / L sulfuric acid solution was added. Stirring was continued, and 2 g white carbon black (silicon dioxide content of 90 wt%) was slowly added dropwise to obtain solution B. The molar ratio of each component in solution B was SiO2: 100 H2O: 0.01R: 0.15H + .

[0049] S3. Solution B and molecular sieve A were mixed and transferred to a crystallization reactor. The temperature was raised to 100°C and crystallized at this constant temperature for 50 hours. After complete crystallization, the temperature was lowered to room temperature. The reaction mixture was separated, washed, and dried at 110°C. Finally, the catalyst sample was calcined at 500°C for 6 hours.

[0050] Example 3

[0051] S1. Add 40g of SBA-16 molecular sieve powder, 3.2g of AuCl3, 6g of tetraethyl orthosilicate (TEOS), and 0.15L of 0.1mol / L NaOH solution into a mortar and mix. After mixing thoroughly, dry the mixture at 100°C. Then, take 30g of the dried sample and place it into an extruder. Add 7.5g of deionized water and stir until evenly mixed. Then, begin molding. The molded molecular sieve is dried at 100°C and recorded as molecular sieve A.

[0052] S2. 0.15 g of hexamethylenetetramine (HMTA) and 82.5 g of deionized water were added to the reactor in sequence and stirred evenly. 83 mL of 0.1 mol / L nitric acid solution was then added. Stirring was continued and 10 g of silica sol (SW-25, with a silica content of 25 wt%) was slowly added dropwise to obtain solution B. The molar ratio of the components in solution B was SiO2:110H2O:0.025R:0.2H + .

[0053] S3. Solution B and molecular sieve A were mixed and transferred to a crystallization reactor. The temperature was raised to 110°C and crystallized at this constant temperature for 60 hours. After complete crystallization, the temperature was lowered to room temperature. The reaction mixture was separated, washed, and dried at 120°C. Finally, the catalyst sample was calcined at 550°C for 7 hours.

[0054] The scanning electron microscopy images of the obtained catalyst samples are shown in Figure 1 . Figure 1 It can be clearly seen that the outer surface of the catalyst sample is a silicon dioxide film (or silicon dioxide shell), and no metal oxide can be seen in the entire field of view, indicating that the metal oxide is distributed on the outer surface of the molecular sieve within the silicon dioxide film. Since the outer surface of the metal oxide is protected by the silicon dioxide film, the metal on the outer surface of the molecular sieve is not easily lost during the reaction, thereby extending the service life of the catalyst.

[0055] Example 4

[0056] S1. Add 40g of SBA-15 molecular sieve powder, 3.2g of PtO, 6g of tetraethyl orthosilicate (TEOS), and 0.3L of 0.1mol / L NaOH solution into a mortar and mix. After mixing evenly, dry the mixture at 130°C. Then, take 30g of the dried sample and place it into an extruder. Add 7.5g of deionized water and stir evenly before forming. The formed molecular sieve is dried at 130°C and recorded as molecular sieve A.

[0057] S2. 4.2 g P104 and 38.9 g deionized water were sequentially added into a reactor, stirred uniformly, then 60 mL of hydrochloric acid solution (0.1 mol / L) was added, continued to be stirred, 5 g of tetraethyl orthosilicate (TEOS) was slowly added dropwise to obtain solution B, and the molar ratio of each component in solution B was SiO2:90H2O:0.03R:0.25H + .

[0058] S3. After mixing solution B and molecular sieve A, they were transferred into a crystallization kettle, the temperature was raised to 130°C, and constant temperature crystallization was carried out for 90 h. After complete crystallization, when the temperature dropped to room temperature, the reacted mixture was separated, washed, and dried at 130°C. Finally, after calcination at 400°C for 8 h, a catalyst sample was obtained.

[0059] Example 5

[0060] S1. 40 g of SBA-15 molecular sieve powder, 3.2 g of PdCl2, 6 g of tetraethyl orthosilicate (TEOS), and 0.3 L of 0.1 mol / L NaOH solution were added into a mortar for mixing. After uniform mixing, they were dried at 130°C. Then, 30 g of the dried sample was put into an extruder, 7.5 g of deionized water was added, and stirring was carried out. After that, the shaped molecular sieve was dried at 120°C, and was recorded as molecular sieve A.

[0061] S2. 4.2 g P104 and 38.9 g deionized water were sequentially added into a reactor, stirred uniformly, then 60 mL of hydrochloric acid solution (0.1 mol / L) was added, continued to be stirred, 5 g of tetraethyl orthosilicate (TEOS) was slowly added dropwise to obtain solution B, and the molar ratio of each component in solution B was SiO2:90H2O:0.03R:0.25H + .

[0062] S3. After mixing solution B and molecular sieve A, they were transferred into a crystallization kettle, the temperature was raised to 130°C, and constant temperature crystallization was carried out for 90 h. After complete crystallization, when the temperature dropped to room temperature, the reacted mixture was separated, washed, and dried at 130°C. Finally, after calcination at 400°C for 8 h, a catalyst sample was obtained.

[0063] Comparative Example 1

[0064] 40g SBA-15 molecular sieve powder and 14.2g pseudo-boehmite (Al2O3 content is 70wt%) are added to a mixer and mixed. After mixing evenly, 25.8g dilute nitric acid (HNO3 content is 6.3wt%) is added and kneaded, and then 15.5g deionized water is added and kneaded. The kneaded material is then placed in an extruder for molding. The molded molecular sieve is dried at 130°C and then calcined at 400°C for 8h. The calcined molecular sieve is then mixed with 3.2g AuCl3 for 4h, dried at 130°C, and then calcined at 400°C for 8h to obtain an Au / SBA-15 catalyst sample.

[0065] Comparative Example 2

[0066] S1. Add 40g of SBA-15 molecular sieve powder, 3.2g of AuCl3, 6g of tetraethyl orthosilicate (TEOS), and 2.1L of 0.1mol / L NaOH solution into a mortar and mix. After mixing evenly, dry the mixture at 130°C. Then, take 30g of the dried sample and place it into an extruder. Add 7.5g of deionized water and stir evenly before forming. The formed molecular sieve is dried at 130°C and recorded as molecular sieve A.

[0067] S2. 4.2 g of P104 and 38.9 g of deionized water were added to the reactor in sequence and stirred evenly. 60 mL of hydrochloric acid solution (0.1 mol / L) was then added. Stirring was continued and 5 g of tetraethyl orthosilicate (TEOS) was slowly added dropwise to obtain solution B. The molar ratio of the components in solution B was SiO2: 90 H2O: 0.03R: 0.25H + .

[0068] S3. Solution B and molecular sieve A were mixed and transferred to a crystallization kettle. The temperature was raised to 130°C and crystallized at this constant temperature for 90 hours. After complete crystallization, the temperature was lowered to room temperature. The reaction mixture was separated, washed, and dried at 130°C. Finally, the catalyst sample was calcined at 400°C for 8 hours.

[0069] Catalytic effect evaluation

[0070] The catalyst samples prepared in the examples and comparative examples were used for the complete oxidation of benzene, and the specific process was as follows:

[0071] The complete oxidation reaction of benzene was carried out in a fixed bed reactor. 63 mg of catalyst was placed in a quartz reaction tube, and the upper and lower sides of the catalyst were sealed with quartz wool. A thermocouple on the outside of the reaction tube was used to control the temperature of the reactor, and another thermocouple was inserted into the inside of the quartz reaction tube to measure the temperature of the catalyst bed. Air (flow rate of 98 mL / min) and reaction gas were introduced into the two gas lines, and the reactant concentration was approximately 5.6 g / m3 (The low-temperature thermostat was maintained at 11°C, and the air flow rate was 2 mL / min.) After mixing, the mixture was introduced into the reactor. When the reactor bed temperature reached 550°C and stabilized for approximately 20 minutes, the catalyst activity was measured, and the benzene concentration in the exhaust gas was measured by gas chromatography. The test results are shown in Table 1.

[0072] Table 1

[0073] Benzene conversion rate (%) Example 1 90.5 Example 2 90.9 Example 3 91.6 Example 4 92.7 Comparative Example 1 43.9 Comparative Example 2 15.8

[0074] From the above test results, it can be seen that the catalysts prepared by the preparation method provided by the present invention in Examples 1-4 showed excellent catalytic performance in the complete oxidation reaction of benzene.

[0075] Comparative Example 1 uses the traditional loading impregnation method. Firstly, due to the addition of adhesives during the molding process, the traditional method has relatively fewer active sites in the catalyst of the same mass. Secondly, due to the lack of protection of the outer surface silica film, the metals on the surface of these molecular sieves are very likely to be lost during the reaction, resulting in a decrease in catalyst activity.

[0076] In Comparative Example 2, due to the addition of too much base, the molecular sieve skeleton itself collapsed while the silicon source was hydrolyzed to form a silicon dioxide film and a sticky network, resulting in very low catalytic activity.

[0077] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a catalyst for the complete oxidation reaction of benzene, characterized in that: The following steps are involved: S1. Mixing SBA molecular sieve powder, a metal source, a first silicon source, and an alkaline solution to obtain a mixture, and shaping and drying the mixture to obtain molecular sieve A; wherein the metal source comprises at least one of a gold source, a platinum source, and a palladium source; S2. Mixing the organic template R, water, a second silicon source, and an acid to obtain a solution B; S3. Adding solution B to molecular sieve A, hydrothermally crystallizing, filtering, washing, drying, and calcining to obtain a catalyst for the complete oxidation of benzene; The first silicon source includes at least one of ethyl orthosilicate, silica sol, and water glass; the alkali solution contains OH - The ratio of the molar amount of the base calculated as SiO2 to the molar amount of the first silicon source calculated as SiO2 is 0.5~4:

1.

2. The preparation method according to claim 1, characterized in that The gold source includes one or more of gold oxide, hydroxide, sulfide, chloride, and cyanide; and / or the platinum source includes one or more of platinum oxide, hydroxide, sulfide, chloride, and cyanide; and / or the palladium source includes one or more of palladium oxide, hydroxide, sulfide, chloride, and cyanide.

3. The preparation method according to claim 1, characterized in that The SBA molecular sieve raw powder includes SBA-15 molecular sieve raw powder or SBA-16 molecular sieve raw powder; And / or, the first silicon source is tetraethyl orthosilicate; And / or, the alkali in the alkali solution comprises NaOH.

4. The preparation method according to any one of claims 1 to 3, characterized in that The organic template R includes at least one of an amphiphilic nonionic triblock surfactant and hexamethylenetetramine; And / or, the second silicon source includes at least one of white carbon black, ethyl orthosilicate, sodium silicate, and silica sol; And / or, the acid includes at least one of hydrochloric acid, sulfuric acid, and nitric acid.

5. The preparation method according to claim 4, characterized in that The amphiphilic nonionic triblock surfactant includes at least one of F127, F108, P123, and P104; And / or, the second silicon source is tetraethyl orthosilicate; And / or, the acid is hydrochloric acid.

6. The preparation method according to any one of claims 1 to 3, characterized in that The mass ratio of the metal source to the SBA molecular sieve raw powder is 1-10:100; And / or, the mass ratio of the first silicon source to the SBA molecular sieve raw powder is 1:5-10; And / or, the alkali solution contains OH - The ratio of the molar amount of the base calculated as SiO2 to the molar amount of the first silicon source calculated as SiO2 is 0.5~3.5:

1.

7. The preparation method according to any one of claims 1 to 3, characterized in that The molar ratio of each component in the solution B is SiO2:a H2O:b R:c H + , where the value of a is 80~200, the value of b is 0.005~0.030, and the value of c is 0.10~0.

25.

8. The preparation method according to claim 7, characterized in that The value of a is 100 to 160, and / or the value of b is 0.010 to 0.025, and / or the value of c is 0.15 to 0.

20.

9. The preparation method according to any one of claims 1 to 3, characterized in that The mixture in step S1 is first dried, and then the dried mixture is mixed with water and then formed.

10. The preparation method according to claim 9, characterized in that The mass of water mixed with the dried mixture is 10% to 30% of the mass of the dried mixture.

11. The preparation method according to claim 10, characterized in that: The mass of water mixed with the dried mixture is 15% to 25% of the mass of the dried mixture.

12. The preparation method according to any one of claims 1 to 3, characterized in that The drying temperature in step S1 is 100-140°C; And / or, the crystallization temperature in step S3 is 80-130° C.; the crystallization time is 24-90 h; And / or, the drying temperature in step S3 is 100-140°C; And / or, the calcination temperature in step S3 is 400-700° C.; and the calcination time is 5-8 h.

13. The preparation method according to claim 12, characterized in that The drying temperature in step S1 is 110-130°C; and / or, the crystallization temperature in step S3 is 90-120° C.; and / or, the crystallization time is 40-70 h; And / or, the drying temperature in step S3 is 110-130° C.; And / or, the calcination temperature in step S3 is 500-600°C.

14. A catalyst for the complete oxidation reaction of benzene, prepared by the preparation method according to any one of claims 1 to 13, wherein the surface of the catalyst for the complete oxidation reaction of benzene comprises a silica shell layer.

15. The catalyst according to claim 14, characterized in that The particle diameter of the catalyst is 30-50 nm.

16. A method for complete oxidation of benzene, wherein the reaction is catalyzed by the catalyst prepared by the preparation method according to any one of claims 1 to 13 or the catalyst according to claim 14 or 15.

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