Molybdenum-based composite material, oxidative desulfurization catalyst and preparation method and application thereof

Abstract

The invention discloses a molybdenum-based composite material, an oxidative desulfurization catalyst and a preparation method and application thereof, and belongs to the technical field of oil product oxidative desulfurization. The preparation method of the molybdenum-based composite material comprises the following steps: dissolving zinc nitrate hexahydrate and molybdenum acetylacetonate in methanol to obtain a solution A; dissolving 2-methylimidazole in methanol to obtain a solution B; mixing and stirring the solution A and the solution B to obtain a first intermediate product; dissolving melamine and the first intermediate product in ethanol, and mixing and stirring to obtain a second intermediate product; and heating the second intermediate product to 800-900 DEG C at a speed of 5-8 DEG C / min, and carrying out heat preservation to obtain the molybdenum-based composite material. In addition, the invention further provides the molybdenum-based composite material prepared by the preparation method or application of the molybdenum-based composite material in fuel oil oxidative desulfurization. The molybdenum-based composite material prepared by the invention can realize rapid desulfurization.

Description

Technical Field

[0001] The present invention relates to the technical field of oil oxidation desulfurization, and in particular to a molybdenum-based composite material, an oxidation desulfurization catalyst, and a preparation method and application thereof. Background Art

[0002] With growing environmental awareness and increasingly stringent environmental regulations, countries around the world have imposed strict limits on sulfur content in fuels, with some regions even specifying a limit of 10 ppm. To address these regulations, many industries have begun reducing fuel use, but fuel remains irreplaceable in many areas. Consequently, the development of a new generation of fuel desulfurization technology is essential to further reduce sulfur content.

[0003] At present, the mainstream fuel desulfurization technology at home and abroad is hydrodesulfurization (HDS), which requires harsh operating conditions to achieve satisfactory sulfide removal efficiency (such as high temperature and high pressure). In addition, in non-hydrodesulfurization, the reaction conditions of oxidative desulfurization are mild, requiring only relatively low temperature and pressure. At the same time, the desulfurization efficiency is significantly higher than that of biological desulfurization and extractive desulfurization, and clean fuel can be produced efficiently at a lower cost.

[0004] Single-atom catalysts (SACs) possess a single metal site, with the atoms uniformly dispersed on a substrate. Due to the ultra-high utilization of their central atom, precisely tunable electronic structure activity, and high selectivity, they exhibit unparalleled activity, making them a cutting-edge catalyst. Research directions in the field of catalysis have made them a cutting-edge research direction in catalysis due to their ultra-high utilization of their central atom, precisely tunable electronic structure activity, and high selectivity.

[0005] The industrial application of single-atom catalysts in oxidative desulfurization (ODS) still faces many challenges. Currently, the key and most challenging aspects of ODS lie in designing and synthesizing novel single-atom catalysts that can increase the number of active sites, adjust the pore size, and manipulate their structural composition to enhance catalyst stability and achieve rapid desulfurization. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical deficiencies, provide a molybdenum-based composite material, an oxidative desulfurization catalyst, and a preparation method and application thereof, and solve the technical problem of how to achieve rapid desulfurization in the prior art.

[0007] In order to achieve the above technical objectives, the technical solution of the present invention provides a method for preparing a molybdenum-based composite material, comprising the following steps:

[0008] S1. Dissolve zinc nitrate hexahydrate and molybdenum acetylacetonate in methanol and sonicate to obtain solution A; dissolve 2-methylimidazole in methanol and sonicate to obtain solution B;

[0009] S2, mixing solution A and solution B with stirring to obtain a first intermediate product Mo-ZIF-8;

[0010] S3, dissolving melamine and the first intermediate product Mo-ZIF-8 in ethanol and mixing and stirring to obtain a second intermediate product Mo-ZIF-8 / M;

[0011] S4. The second intermediate product Mo-ZIF-8 / M is heated to 800-900° C. at a rate of 5-8° C. / min under an inert gas atmosphere and kept at this temperature to obtain the molybdenum-based composite material.

[0012] In any embodiment, in step S1, the mass ratio of the zinc nitrate hexahydrate to the molybdenum acetylacetonate is 5:(0.2-0.3); and / or, in step S2, the solution A and the solution B are mixed and stirred according to a mass ratio of the zinc nitrate hexahydrate in the solution A to the 2-methylimidazole in the solution B of 5:(10-13).

[0013] In any embodiment, in step S1, the ultrasonic time for obtaining solution A or the ultrasonic time for obtaining solution B is 30-40 min; and / or, in step S2, the stirring time is 10-13 hours; and / or, in step S3, the stirring time is 2-3 hours.

[0014] In any embodiment, in step S3, the mass ratio of the melamine to the first intermediate product Mo-ZIF-8 is 1:(1-1.5).

[0015] In any embodiment, in step S4, the insulation time is 2-3 hours.

[0016] In any embodiment, in step S4, the inert gas is argon.

[0017] In addition, the present invention also provides a molybdenum-based composite material prepared by the above preparation method.

[0018] In addition, the present invention also provides an oxidative desulfurization catalyst, comprising the molybdenum-based composite material prepared by the above preparation method or the above molybdenum-based composite material.

[0019] In addition, the present invention also proposes the use of the molybdenum-based composite material prepared by the above preparation method or the above molybdenum-based composite material in the oxidative desulfurization of fuel.

[0020] In the above application, the fuel, the oxidant and the molybdenum-based composite material are mixed and reacted, the volume ratio of the oxidant to the fuel is (0.005-0.0055):1, and the amount ratio of the molybdenum-based composite material to the fuel is (0.004-0.005) g:1 mL.

[0021] Compared with the prior art, the present invention has the following advantages: the present invention provides a method for preparing a molybdenum-based composite material, comprising the following steps: S1, dissolving zinc nitrate hexahydrate and molybdenum acetylacetonate in methanol and ultrasonically obtaining a solution A; dissolving 2-methylimidazole in methanol and ultrasonically obtaining a solution B; S2, mixing the solution A and the solution B to obtain a first intermediate product Mo-ZIF-8; S3, dissolving melamine and the first intermediate product Mo-ZIF-8 in ethanol and mixing and stirring to obtain a second intermediate product Mo-ZIF- 8 / M; S4, heating the second intermediate product Mo-ZIF-8 / M to 800-900°C at 5-8°C / min under an inert gas atmosphere and keeping it warm to obtain the molybdenum-based composite material; dispersing the molybdenum atoms through solution A so that the atomic utilization rate is close to 100%, greatly improving the catalytic activity, adding melamine to create mesopores on the carbon matrix, enhancing the adsorption capacity of the molybdenum-based composite material and the mass transfer rate of the reaction substrate, and then regulating the coordination number and geometric configuration of the Mo atoms and the N atoms through the calcination temperature, thereby achieving rapid desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the HAADF-STEM image of the molybdenum-based composite material prepared in Example 1.

[0023] Figure 2 The XANES graph and wavelet transform graph of the molybdenum-based composite material prepared in Example 1 are shown; wherein, Figure 2 (a) Mo K-edge XANES images of Mo foil, MoO2, MoO3 and the molybdenum-based composite material prepared in Example 1; Figure 2 (b) K-edge EXAFS graphs of Mo foil, MoO2, MoO3 and prepared in Example 1; Figure 2 (c) Mo K-edge EXAFS fitting diagram of the molybdenum-based composite material prepared in Example 1; Figure 2 (d) Wavelet transform image of the molybdenum-based composite material obtained in Example 1; Figure 2 (e) is the wavelet transform image of MoO3; Figure 2 (f) is the wavelet transform image of Mo foil.

[0024] Figure 3 This is the pore size distribution diagram of the molybdenum-based composite material prepared in Example 1. DETAILED DESCRIPTION

[0025] The "ranges" disclosed herein are defined in terms of lower and upper limits, where a given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined arbitrarily, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a particular parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also contemplated. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5. In this application, unless otherwise indicated, the numerical range "a to b" is a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0026] Unless otherwise specified, the terms "include" and "comprising" used in this application may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0027] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0028] This specific embodiment provides a method for preparing a molybdenum-based composite material, comprising the following steps:

[0029] S1, zinc nitrate hexahydrate, platinum acetylacetonate were dissolved in methanol and ultrasonicated for 30-40min to obtain solution A; 2-methylimidazole was dissolved in methanol and ultrasonicated for 30-40min to obtain solution B; the mass ratio of the zinc nitrate hexahydrate and the platinum acetylacetonate was 5: (0.2-0.3);

[0030] S2, according to the mass ratio of zinc nitrate hexahydrate in the A solution and 2-methylimidazole in the B solution of 5: (10-13), mixing the A solution and the B solution for 10-13 hours to obtain the first intermediate product Mo-ZIF-8;

[0031] S3, dissolving melamine and the first intermediate product Mo-ZIF-8 in ethanol and mixing and stirring for 2-3 hours to obtain a second intermediate product Mo-ZIF-8 / M; the mass ratio of the melamine to the first intermediate product Mo-ZIF-8 is 1:(1-1.5);

[0032] S4. The second intermediate product Mo-ZIF-8 / M is heated to 800-900° C. at a rate of 5-8° C. / min under an inert gas atmosphere and kept at this temperature for 2-3 hours to obtain the molybdenum-based composite material; the inert gas is argon.

[0033] This specific embodiment also provides a molybdenum-based composite material, which is prepared by the above preparation method.

[0034] This specific embodiment also provides an oxidative desulfurization catalyst, comprising the molybdenum-based composite material prepared by the above preparation method or the above molybdenum-based composite material.

[0035] This specific embodiment also proposes the use of the molybdenum-based composite material prepared by the above preparation method or the above molybdenum-based composite material in the oxidative desulfurization of fuel, including mixing the fuel, an oxidant and the molybdenum-based composite material for reaction, wherein the volume ratio of the oxidant to the fuel is (0.005-0.0055):1, and the amount ratio of the molybdenum-based composite material to the fuel is (0.004-0.005) g:1 mL.

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] In the present invention, references to “some embodiments”, “this embodiment”, examples, etc. describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

[0038] If similar descriptions of "first / second" appear in the application documents, the following explanation is added. In the following description, the terms "first\second\third" are merely used to distinguish similar objects and do not represent a specific order of the objects. It can be understood that "first\second\third" can be interchanged with the specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0039] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0040] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0041] Example 1

[0042] This embodiment provides a molybdenum-based composite material, which is prepared by the following steps:

[0043] S1. Dissolve 5.00 g of zinc nitrate hexahydrate and 0.296 g of molybdenum acetylacetonate in 120 ml of methanol and sonicate for 30 min to obtain solution A; dissolve 11.10 g of 2-methylimidazole in 240 ml of methanol and sonicate for 30 min to obtain solution B;

[0044] S2, mixing the solution A and the solution B and stirring for 12 hours to obtain a first intermediate product Mo-ZIF-8;

[0045] S3, dissolving 1 g of melamine and 1 g of the first intermediate product Mo-ZIF-8 in 50 ml of ethanol and mixing and stirring for 2 hours, washing with ethanol three times and then drying to obtain a second intermediate product Mo-ZIF-8 / M;

[0046] S4. The second intermediate product Mo-ZIF-8 / M is heated to 900° C. at 5° C. / min under an argon atmosphere and kept at this temperature for 2 hours to obtain the molybdenum-based composite material (i.e., m-MoSA-Nx-C).

[0047] Combine Figure 1 It can be seen that the molybdenum atoms (bright spots) are evenly distributed on the carbon layer, combined with Figure 2 It can be concluded that Mo atoms exist in a single atomic form, and their N coordination number is 3, and the average bond length is about Combine Figure 3 It can be seen that the pore size distribution of m-MoSA-Nx-C is between 2 and 10 nm, which is an obvious mesoporous structure.

[0048] Example 2

[0049] This embodiment provides a molybdenum-based composite material, which is prepared by the following steps:

[0050] S1. Dissolve 5.00 g of zinc nitrate hexahydrate and 0.225 g of molybdenum acetylacetonate in 120 ml of methanol and sonicate for 30 min to obtain solution A; dissolve 12.50 g of 2-methylimidazole in 240 ml of methanol and sonicate for 30 min to obtain solution B;

[0051] S2, mixing the solution A and the solution B and stirring for 11 hours to obtain a first intermediate product Mo-ZIF-8;

[0052] S3, dissolving 1 g of melamine and 1.2 g of the first intermediate product Mo-ZIF-8 in 50 ml of ethanol and mixing and stirring for 2.5 hours, washing with ethanol three times and then drying to obtain a second intermediate product Mo-ZIF-8 / M;

[0053] S4. The second intermediate product Mo-ZIF-8 / M is heated to 850° C. at a rate of 6° C. / min under an argon atmosphere and kept at this temperature for 2.5 hours to obtain the molybdenum-based composite material.

[0054] Example 3

[0055] This embodiment provides a molybdenum-based composite material, which is prepared by the following steps:

[0056] S1. Dissolve 5.00 g of zinc nitrate hexahydrate and 0.211 g of molybdenum acetylacetonate in 120 ml of methanol and sonicate for 40 min to obtain solution A; dissolve 10.25 g of 2-methylimidazole in 240 ml of methanol and sonicate for 40 min to obtain solution B;

[0057] S2, mixing the solution A and the solution B and stirring for 10 hours to obtain a first intermediate product Mo-ZIF-8;

[0058] S3, dissolving 1 g of melamine and 1.5 g of the first intermediate product Mo-ZIF-8 in 50 ml of ethanol and mixing and stirring for 3 hours, washing with ethanol three times and then drying to obtain a second intermediate product Mo-ZIF-8 / M;

[0059] S4. The second intermediate product Mo-ZIF-8 / M is heated to 800° C. at a rate of 8° C. / min under an argon atmosphere and kept at this temperature for 3 hours to obtain the molybdenum-based composite material.

[0060] Example 4

[0061] This embodiment provides a molybdenum-based composite material, which is prepared by the following steps:

[0062] S1. Dissolve 5.00 g of zinc nitrate hexahydrate and 0.3 g of molybdenum acetylacetonate in 120 ml of methanol and sonicate for 35 min to obtain solution A; dissolve 13 g of 2-methylimidazole in 240 ml of methanol and sonicate for 35 min to obtain solution B;

[0063] S2, mixing the solution A and the solution B and stirring for 13 hours to obtain the first intermediate product Mo-ZIF-8;

[0064] S3, dissolving 1 g of melamine and 1 g of the first intermediate product Mo-ZIF-8 in 50 ml of ethanol and mixing and stirring for 2.5 hours, washing with ethanol three times and then drying to obtain a second intermediate product Mo-ZIF-8 / M;

[0065] S4. The second intermediate product Mo-ZIF-8 / M is heated to 850° C. at a rate of 6° C. / min under an argon atmosphere and kept at this temperature for 2.5 hours to obtain the molybdenum-based composite material.

[0066] Related applications

[0067] The model oil is prepared by adding thiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene into n-octane to prepare a 500 ppm model oil.

[0068] In the application of fuel oxidation desulfurization, the volume ratio of oxidant to fuel is 0.0055:1, the molar ratio of oxidant to sulfur content in fuel is 6:1, the amount ratio of catalyst to fuel is 0.005g:1mL; the sulfur content in fuel is 500ppm.

[0069] In the fuel oil oxidative desulfurization method, the oxidant is a hydrogen peroxide solution containing 25%-35% H2O2 by volume. In the following application example, the hydrogen peroxide solution contains 30% H2O2 by volume. In the fuel oil oxidative desulfurization method, the reaction temperature is 40-70°C and the mixing reaction time is 50 minutes.

[0070] Preparation of model oil: 1 g of dibenzothiophene (DBT) and 0.7 g of tetradecane were added to 500 mL of n-octane and ultrasonicated for 30 min to prepare a 500 ppm simulated sulfur-containing fuel.

[0071] 0.046 g of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and 0.0367 mL of tetradecane were added to 20 mL of n-octane and ultrasonicated for 30 minutes to prepare a 500 ppm simulated sulfur-containing fuel.

[0072] 0.0184 g of thiophene (BT) and 0.0367 mL of tetradecane were added to 20 mL of n-octane and ultrasonicated for 30 min to prepare a 500 ppm simulated sulfur-containing fuel.

[0073] In a round-bottom flask equipped with a magnetic stirrer, the molybdenum-based composite catalyst prepared in Example 1 was added to the model oil. After reaching the reaction temperature, an oxidant was added. The model oil was removed at regular intervals, acetonitrile was used as an extractant, and the supernatant was collected. The sulfur content in the oil was then detected by gas chromatography (GC-FID), and the desulfurization rate was calculated:

[0074]

[0075] Application Example 1

[0076] The model oil (DBT) was heated to 40°C and maintained for 20 minutes, and then 0.03 g of catalyst and 66 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 94.30%.

[0077] Application Example 2

[0078] The model oil (DBT) was heated to 50° C. and maintained for 20 minutes. 0.03 g of catalyst and 66 μL of H 2 O 2 were then added. The reaction was continued for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0079] Application Example 3

[0080] The model oil (DBT) was heated to 60°C and maintained for 20 minutes, and then 0.03 g of catalyst and 66 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0081] Application Example 4

[0082] The model oil (DBT) was heated to 70°C and maintained for 20 minutes, and then 0.03 g of catalyst and 66 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0083] Application Example 5

[0084] The model oil (DBT) was heated to 60°C and maintained for 20 minutes, and then 0.03g of catalyst and 44μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 92.13%.

[0085] Application Example 6

[0086] The model oil (DBT) was heated to 60°C and maintained for 20 minutes, and then 0.03 g of catalyst and 55 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0087] Application Example 7

[0088] The model oil (DBT) was heated to 60°C and maintained for 20 minutes, and then 0.03 g of catalyst and 66 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0089] Application Example 8

[0090] The model oil (DBT) was heated to 60°C and maintained for 20 minutes, and then 0.03 g of catalyst and 77 μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0091] Application Example 9

[0092] The simulated oil (BT) was heated to 60°C and maintained for 20 minutes, and then 0.03g of catalyst and 55μL of H2O2 were added. The reaction was carried out for 40 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 77.62%.

[0093] Application Example 10

[0094] The simulated oil (4,6-DMDBT) was heated to 60°C and maintained for 20 minutes, and then 0.03 g of catalyst and 55 μL of H2O2 were added. The reaction was carried out for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0095] Table 1 Test results of application examples 1-10

[0096]

[0097]

[0098] As shown in Table 1, the optimal reaction temperature for Examples 1, 2, 3, and 4 is 50°C. The optimal oxidant dosage for Examples 5, 6, 7, and 8 is 55 μL, indicating a molar ratio of oxidant to fuel sulfur of 5. Furthermore, the removal rates for BT and 4,6-DMDBT, which are relatively difficult to remove by oxidative desulfurization, are high.

[0099] The catalyst after the reaction was obtained by filtration in Application Example 2. The catalyst was dried to remove the water brought by H2O2. New oil and H2O2 were added again to carry out a circulation experiment. The results are shown in Table 2.

[0100] Table 2 Cycling test when the model oil is DBT

[0101]

[0102]

[0103] It can be seen from Table 2 that after 9 cycles, the desulfurization rate of the catalyst can still reach as high as 97.26%, indicating that the oxidative desulfurization performance of the molybdenum-based composite material prepared in the present invention is stable.

[0104] Comparative Example 1

[0105] The first intermediate product Mo-ZIF-8 prepared in Example 1 was desulfurized according to the steps of Application Example 2. The final measured desulfurization rate was 51.2%, which was much lower than the desulfurization rate of the molybdenum-based composite material prepared in Example 1.

[0106] It should be noted that the molybdenum-based composite materials prepared in Examples 2-4 have desulfurization performance comparable to that of the molybdenum-based composite material prepared in Example 1.

[0107] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a molybdenum-based composite material, characterized in that: The following steps are involved: S1. Dissolve zinc nitrate hexahydrate and molybdenum acetylacetonate in methanol and perform ultrasonic treatment to obtain solution A; dissolve 2-methylimidazole in methanol and perform ultrasonic treatment to obtain solution B; S2, mixing solution A and solution B with stirring to obtain a first intermediate product Mo-ZIF-8; S3, dissolving melamine and the first intermediate product Mo-ZIF-8 in ethanol and mixing and stirring to obtain a second intermediate product Mo-ZIF-8 / M; S4. The second intermediate product Mo-ZIF-8 / M is heated to 800-900° C. at 5-8° C. / min under an inert gas atmosphere and then kept at this temperature to obtain the molybdenum-based composite material.

2. The method for preparing the molybdenum-based composite material according to claim 1, characterized in that: In step S1, the mass ratio of the zinc nitrate hexahydrate to the molybdenum acetylacetonate is 5:(0.2-0.3); and / or, in step S2, the A solution and the B solution are mixed and stirred according to the mass ratio of the zinc nitrate hexahydrate in the A solution to the 2-methylimidazole in the B solution being 5:(10-13).

3. The method for preparing the molybdenum-based composite material according to claim 1, characterized in that: In step S1, the ultrasonic time for obtaining solution A or the ultrasonic time for obtaining solution B is 30-40 minutes; and / or, in step S2, the stirring time is 10-13 hours; and / or, in step S3, the stirring time is 2-3 hours.

4. The method for preparing the molybdenum-based composite material according to claim 1, characterized in that: In step S3, the mass ratio of the melamine to the first intermediate product Mo-ZIF-8 is 1:(1-1.5).

5. The method for preparing the molybdenum-based composite material according to claim 1, characterized in that: In step S4, the insulation time is 2-3 hours.

6. The method for preparing the molybdenum-based composite material according to claim 1, characterized in that: In step S4, the inert gas is argon.

7. A molybdenum-based composite material, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 6.

8. An oxidative desulfurization catalyst, characterized in that: The invention comprises a molybdenum-based composite material prepared by the preparation method according to any one of claims 1 to 6 or a molybdenum-based composite material according to claim 7.

9. Use of the molybdenum-based composite material prepared by the preparation method according to any one of claims 1 to 6 or the molybdenum-based composite material according to claim 7 in fuel oxidation desulfurization.

10. The use according to claim 9, characterized in that: The method comprises mixing and reacting fuel oil, an oxidant and a molybdenum-based composite material, wherein the volume ratio of the oxidant to the fuel oil is (0.005-0.0055):1, and the dosage ratio of the molybdenum-based composite material to the fuel oil is (0.004-0.005) g:1 mL.

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