阅读说明：本技术 一种w@mzc核壳结构高效氧化脱硫催化剂及其制备方法和应用 (W @ MZC core-shell structure efficient oxidation desulfurization catalyst and preparation method and application thereof ) 是由 霍全 孙海会 刘素燕 张旭彪 高晶 苗家润 张晓林 齐予铭 王园园 赵佳瑶 郭俊 于 2021-09-09 设计创作，主要内容包括：一种W@MZC核壳结构高效氧化脱硫催化剂及其制备方法和应用,属于核壳结构的构造以及具有磁性的催化剂设计技术领域。本发明提供了一种W@MZC核壳结构高效氧化脱硫催化剂是由ZIF-8和磷钨酸生长包覆MIL-101(Fe)构成的核壳结构。还提供了其制备方法包括：(1)在甲醇溶液中加入2-甲基咪唑搅拌得到溶液A；(2)在甲醇溶液中依次加入MIL-101(Fe)、六水合硝酸锌和磷钨酸充分搅拌得到溶液B；(3)溶液A加入溶液B中,搅拌离心后得前驱体；(4)通氮气对前驱体焙烧,得到W@MZC；(5)对W@MZC干燥得到W@MZC氧化脱硫催化剂。本发明催化剂稳定,重复利用率高,制备过程绿色环保,污染少。(A W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst, a preparation method and an application thereof belong to the technical field of core-shell structure construction and magnetic catalyst design. The invention provides a W @ MZC core-shell structure efficient oxidation desulfurization catalyst which is a core-shell structure formed by growth coating of MIL-101(Fe) by ZIF-8 and phosphotungstic acid. Also provided is a preparation method thereof comprising: (1) adding 2-methylimidazole into the methanol solution, and stirring to obtain a solution A; (2) adding MIL-101(Fe), zinc nitrate hexahydrate and phosphotungstic acid into a methanol solution in sequence, and fully stirring to obtain a solution B; (3) adding the solution A into the solution B, stirring and centrifuging to obtain a precursor; (4) introducing nitrogen to roast the precursor to obtain W @ MZC; (5) and drying the W @ MZC to obtain the W @ MZC oxidative desulfurization catalyst. The catalyst is stable, the repeated utilization rate is high, the preparation process is environment-friendly, and the pollution is less.)

1. The W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized by being of a core-shell structure formed by growth coating of MIL-101(Fe) with ZIF-8 and phosphotungstic acid.

2. The high efficiency oxidative desulfurization catalyst with W @ MZC core-shell structure of claim 1, wherein the ZIF-8 is obtained by the reaction of 2-methylimidazole and zinc nitrate hexahydrate.

3. The W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst of claim 2, wherein the mass ratio of the 2-methylimidazole to the zinc nitrate hexahydrate is 0.5-1.0: 0.15-0.3.

4. A preparation method of a W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst is characterized by comprising the following steps:

(1) adding 2-methylimidazole 0.5-1.0 g into a uniformly stirred methanol solution at room temperature to obtain a solution A;

(2) at room temperature, sequentially adding 5-20 mg of MIL-101(Fe), 0.05-0.1 mmol of zinc nitrate hexahydrate and 30-100 mg of phosphotungstic acid into a uniformly stirred methanol solution, and fully stirring to obtain a solution B;

or at room temperature, sequentially adding 0.10mmol of zinc nitrate hexahydrate, 5-20 mg of MIL-101(Fe) and 30-100 mg of phosphotungstic acid into the uniformly stirred methanol solution, and fully stirring to obtain a solution B;

(3) the solution A is slowly added into the solution B while the solution B is fully stirred, and a precursor is prepared after full stirring and centrifugation;

(4) introducing nitrogen, and roasting the precursor to obtain a porous carbon material W @ MZC with a core-shell structure;

(5) and drying the porous carbon material W @ MZC to obtain the W @ MZC oxidation desulfurization catalyst.

5. The preparation method of the W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst of claim 4, wherein the mass-to-volume ratio of the 2-methylimidazole to the methanol solution in step (1) is 0.5 to 1:20g/mL, the stirring time is 0.5 to 1h, and the mass ratio of the 2-methylimidazole in step (1) to the zinc nitrate hexahydrate in step (2) is 0.5 to 1.0:0.15 to 0.3.

6. The preparation method of the W @ MZC core-shell structure high-efficiency oxidative desulfurization catalyst of claim 4, wherein the mass-to-volume ratio of MIL-101(Fe) to the methanol solution in step (2) is 1-4: 6 mg/mL.

7. The preparation method of the W @ MZC core-shell structure high-efficiency oxidative desulfurization catalyst as claimed in claim 4, wherein in the step (3), the solution A is slowly added in a dropwise manner, and the sufficient stirring time is 20-24 h.

8. The preparation method of the W @ MZC core-shell structure high-efficiency oxidative desulfurization catalyst as claimed in claim 4, wherein the calcination conditions in the step (4) are as follows: under the condition of nitrogen atmosphere, the roasting temperature is 600-1000 ℃, and the preferred roasting temperature is 700-1000 ℃.

9. The preparation method of the W @ MZC core-shell structure high-efficiency oxidative desulfurization catalyst as claimed in claim 4, wherein the drying treatment in step (5) is preferably vacuum drying under the following conditions: the temperature is 80-120 ℃, and the drying time is 12-24 h.

10. The use of the W @ MZC core-shell structure high efficiency oxidative desulfurization catalyst of claim 1 in oxidative desulfurization.

Technical Field

The invention belongs to the technical field of core-shell structure construction and magnetic catalyst design, and particularly relates to a W @ MZC core-shell structure efficient oxidation desulfurization catalyst, and a preparation method and application thereof.

Background

In recent years, with the increasing number of automobiles, the problem of air pollution caused by automobile exhaust is more and more serious. Removal of sulfur compounds from transportation fuels is of great concern in order to mitigate air pollution, such as the release of SOx and sulfate particulate matter from the combustion of unclean sulfur compound-containing fuels. The traditional method for removing sulfur compounds is Hydrodesulfurization (HDS), and the removal of sulfur compounds in crude oil requires extremely high pressure and temperature, and can be converted into elemental sulfur along with the formation of hydrogen sulfide for removal. However, this treatment does not effectively remove all thiopheneic compounds, which are the major constituent of sulfur in diesel fuel. For example, steric hindrance around the sulfur atom of Dibenzothiophene (DBT) and its substituted derivatives (4,6-DMDBT) prevents efficient hydrodesulfurization. In contrast, ODS technology is mild in conditions, low in cost, high in efficiency and free of H consumption₂And the advantages of deep desulfurization and the like are widely concerned in recent decades.

Oxidative Desulfurization (ODS) has been gradually developed as an alternative to Hydrodesulfurization (HDS) in which sulfides are first oxidized to sulfoxides or sulfones, which can be removed by simple extraction, adsorption, distillation, or filtration, etc., due to their increased polarity. The oxidative desulfurization technology can effectively remove DBT and derivatives thereof under mild conditions, and the equipment investment is less. Compared with hydrodesulfurization, oxidative desulfurization is one of the desulfurization methods with energy saving, high efficiency and development prospect. In the Oxidative Desulfurization (ODS) process, many types of oxidants have been tried, such as molecular oxygen, cyclohexanone peroxide, hydrogen peroxide, etc. Wherein H₂O₂It is widely used in ODS because of its low cost, no secondary pollution and remarkable oxidation performance. To date, various (homogeneous) reactants or catalysts have been applied to ODS processes, such as peroxyorganic acids, Bronsted acidic ionic liquids, molecular sieves, transition metal oxides, and polyoxometalates, particularly Polyoxometalates (POMs). However, recovery of POMs from liquid mixtures is difficult, which limits their use in industrial ODS processes. Thus, it is still important to obtain a suitable heterogeneous catalyst.

MOFs have the advantages of high porosity, large specific surface area, easy-to-open metal sites, easy functionalization and the like, and can be used in the technical field of oxidative desulfurization. In the ODS process, further research is needed to develop how to utilize the structural characteristics of MOFs themselves and how to combine with POMs.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to design and provide a W @ MZC core-shell structure efficient oxidation desulfurization catalyst, and a preparation method and application thereof. The porous carbon material constructed by taking MOFs as a precursor realizes regulation and control of the constructed porous carbon material pore channel structure by utilizing the rich topological structure and the continuous adjustable pore diameter of the MOFs, and is beneficial to adsorption and diffusion of sulfur-containing compound molecules. In addition, the metal polyoxometalates are combined with the metal polyoxometalates by utilizing the structural characteristics, so that the metal active sites are enriched, and are well dispersed, and the structure-activity relationship is greatly enhanced. The material thus constructed integrates the advantages of MOFs material, porous carbon material and polyoxometallate, overcomes the respective material defects, and further improves the catalytic activity of the catalyst material. The catalyst has the advantages of high catalytic conversion efficiency, more uniform distribution of active sites, stable structure, repeated recycling, mild use conditions and no secondary pollution.

The W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized by being of a core-shell structure formed by growth coating of MIL-101(Fe) with ZIF-8 and phosphotungstic acid.

The high-efficiency oxidation desulfurization catalyst with the W @ MZC core-shell structure is characterized in that the ZIF-8 is obtained by reacting 2-methylimidazole with zinc nitrate hexahydrate.

The W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized in that the mass ratio of the 2-methylimidazole to the zinc nitrate hexahydrate is 0.5-1.0: 0.15-0.3.

A preparation method of a W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst is characterized by comprising the following steps:

(1) adding 2-methylimidazole 0.5-1.0 g into a uniformly stirred methanol solution at room temperature to obtain a solution A;

(2) at room temperature, sequentially adding 5-20 mg of MIL-101(Fe), 0.05-0.1 mmol of zinc nitrate hexahydrate and 30-100 mg of phosphotungstic acid into a uniformly stirred methanol solution, and fully stirring to obtain a solution B;

or at room temperature, sequentially adding 0.10mmol of zinc nitrate hexahydrate, 5-20 mg of MIL-101(Fe) and 30-100 mg of phosphotungstic acid into the uniformly stirred methanol solution, and fully stirring to obtain a solution B;

(3) the solution A is slowly added into the solution B while the solution B is fully stirred, and a precursor is prepared after full stirring and centrifugation;

(4) introducing nitrogen, and roasting the precursor to obtain a porous carbon material W @ MZC with a core-shell structure;

(5) and drying the porous carbon material W @ MZC to obtain the W @ MZC oxidation desulfurization catalyst.

The preparation method of the W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized in that the mass-volume ratio of 2-methylimidazole to a methanol solution in the step (1) is 0.5-1: 20g/mL, the stirring time is 0.5-1 h, and the addition mass ratio of 2-methylimidazole in the step (1) to zinc nitrate hexahydrate in the step (2) is 0.5-1.0: 0.15-0.3.

The preparation method of the W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized in that the mass-volume ratio of MIL-101(Fe) to a methanol solution in the step (2) is 1-4: 6 mg/mL.

The preparation method of the W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized in that a dropwise adding mode is adopted when the solution A is slowly added in the step (3), and the sufficient stirring time is 20-24 hours.

The preparation method of the W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst is characterized in that the roasting conditions in the step (4) are as follows: under the condition of nitrogen atmosphere, the roasting temperature is 600-1000 ℃, and the preferred roasting temperature is 700-1000 ℃.

The preparation method of the W @ MZC core-shell structure efficient oxidation desulfurization catalyst is characterized in that the drying treatment in the step (5) is preferably vacuum drying, and the vacuum drying conditions are as follows: the temperature is 80-120 ℃, and the drying time is 12-24 h.

The W @ MZC core-shell structure high-efficiency oxidation desulfurization catalyst is applied to oxidation desulfurization.

The dosage of the 2-methylimidazole and the zinc nitrate hexahydrate corresponds to each other so as to control the structure and the appearance of the ZIF-8; the addition content of MIL-101(Fe) controls the nucleation size; the content of phosphotungstic acid added into the system is used for regulating and controlling the activity of the catalyst; the sequence of addition of MIL-101(Fe), zinc nitrate hexahydrate and phosphotungstic acid was used to control the elemental distribution.

The stirring time and temperature in the preparation method steps are controlled, so that the components in the reaction can be fully contacted and completely reacted, and the preparation efficiency is improved; in the step (2), the adding sequence of the plurality of substances can improve the utilization rate of each substance, and the structure distribution of the synthetic material is more uniform. And (4) roasting at 700-1000 ℃, and further observing the porous carbon materials prepared at different temperatures to obtain the porous carbon material with stable structure and proper pore size. And the vacuum drying in the step (5) removes the internal moisture of the material, so that the material is more easily contacted with a sulfur substrate, and the reaction efficiency is improved.

The invention has the following beneficial effects:

the invention has the advantages of simple process, high catalytic conversion efficiency of the catalyst, more uniform distribution of active sites, stable structure, repeated recycling, mild use conditions and less pollution. The prepared magnetic core-shell oxidative desulfurization catalyst has good oxidative desulfurization performance, and the removal rate of dibenzothiophene in 60min is as high as 99%; the prepared catalyst has magnetism and is convenient to recover.

Drawings

FIG. 1 is an XRD spectrum of a W @ MZC sample;

FIG. 2 is a Raman spectrum of a W @ MZC sample;

FIG. 3 is a HAADF-STEM map of the W @ MZC samples.

Detailed Description

The present invention will be described in further detail with reference to the following examples and the accompanying drawings.

A preparation method of an MIL-101(Fe) core-shell structure efficient oxidation desulfurization catalyst is coated by ZIF-8 and HPW growth, the W @ MZC oxidation desulfurization catalyst is a phosphotungstic acid modified MOFs derived porous carbon oxidation desulfurization catalyst, wherein MIL-101(Fe) derived porous carbon is used as a magnetic core, and HPW and ZIF-8 derived porous carbon are used as shells to jointly form a core-shell structure catalytic material with excellent performance.

The invention comprises the following steps:

(1) adding 2-methylimidazole into a methanol solution which is stirred at a constant speed at room temperature to obtain a solution A;

(2) at room temperature, adding MIL-101(Fe), zinc nitrate hexahydrate and phosphotungstic acid into a methanol solution which is stirred at a constant speed in sequence, and fully stirring to obtain a solution B;

(3) slowly adding the solution A into the solution B under the condition that the solution B is fully stirred, fully stirring, and centrifuging to obtain a composite material of MIL-101(Fe), ZIF-8 and phosphotungstic acid, wherein the composite material is named as MIL @ ZIF-HPW;

(4) introducing nitrogen into a tubular furnace, and roasting the precursor MIL @ ZIF-HPW to obtain a porous carbon material W @ MZC with a core-shell structure;

(5) the composite material needs further drying treatment, and vacuum drying is adopted to obtain the W @ MZC oxidation desulfurization catalyst.

The contents of the 2-methylimidazole in the step (1), the MIL-101(Fe) in the step (2), zinc nitrate hexahydrate and phosphotungstic acid added are 0.5-1.0 g, 5-20 mg and 30-100 mg respectively.

As shown in figure 1, the XRD spectrum of the W @ MZC-x carbon material obtained by roasting the MIL @ ZIF-HPW-x material at high temperature is shown. As can be seen from the figure, the diffraction peaks at 30.2 °, 35.6 °, 43.2 ° and 62.9 ° correspond to γ -Fe₂O₃(ref. PDF #39-1346), which shows that magnetic gamma-Fe is successfully introduced into the W @ MZC catalytic material₂O₃Species of the species.

As shown in fig. 2, the raman spectrum of the W @ MZC catalytic material is shown. As can be seen in the figure, except at Raman shifts of about 1348 and 1587cm^-1Shows a D peak and a G peak of a C atom crystal at about 684 and 805cm^-1The characteristic peak of (A) represents the stretching vibration of the O-W-O bond, and is about 260cm^-1The characteristic peak shows the bending vibration of the W-O-W bond, which shows that the tungsten oxide of the active species is successfully introduced into the W @ MZC catalytic material.

As shown in FIG. 3, is a HAADF-STEM plot of the W @ MZC-80 sample. The distribution of elements C, O, Fe, Zn, P and W can be clearly observed, the elements Zn and W are obviously distributed in the outer layer of the material, the element Fe is mainly distributed in the interior of the material, and in the porous carbon material with the layered and graphite-like structure, metal nano particles contained in the original ZIF-8, MIL-101(Fe) and HPW structures are wrapped by a carbon matrix and have the characteristic of high dispersion. This fully demonstrates the successful synthesis of core-shell structured catalysts.

Example 1:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 5mg of MIL-101(Fe) for stirring until the solution is light orange red, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 700 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 2:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 5mg of MIL-101(Fe) for stirring until the solution is light orange red, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 800 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 3:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 5mg of MIL-101(Fe) for stirring until the solution is light orange red, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 4:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 5mg of MIL-101(Fe) for stirring until the solution is light orange red, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 1000 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 5:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 6:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 20mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 7:

under the condition of room temperature, adding 0.90g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 8:

under the condition of room temperature, adding 1.0g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 9:

under the condition of room temperature, adding 0.70g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 10:

under the condition of room temperature, adding 0.60g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type MZC-W oxidative desulfurization catalyst.

Example 11:

under the condition of room temperature, adding 0.50g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 50mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-50; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-50 type oxidative desulfurization catalyst.

Example 12:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 30mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-30; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-30 type oxidative desulfurization catalyst.

Example 13:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 80mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-80; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-80 type oxidative desulfurization catalyst.

Example 14:

under the condition of room temperature, adding 0.80g of 2-methylimidazole into 20mL of methanol solution which is stirred at a constant speed, and stirring at a constant speed for 30min to fully dissolve the 2-methylimidazole to obtain a solution A; adding 0.27g of zinc nitrate hexahydrate into 30mL of methanol solution stirred at a constant speed, fully stirring the solution to be transparent, then adding 10mg of MIL-101(Fe) for stirring until the solution is light orange, and then adding 100mg of phosphotungstic acid until the solution is uniformly mixed to obtain a solution B; and slowly adding the solution A into the solution B while stirring, stirring at a constant speed for 24 hours at room temperature to obtain an orange-red milky precipitate, and centrifuging, drying and grinding to obtain a powdery precursor MIL @ ZIF-HPW sample. Roasting the MIL @ ZIF-HPW prepared at 900 ℃ under the protection of inert gas high-purity nitrogen to obtain a magnetic core-shell structure porous carbon material named as W @ MZC-100; and (3) placing the obtained sample in a vacuum drying oven, and drying at 100 ℃ for 12h to obtain the W @ MZC-100 type oxidative desulfurization catalyst.

The oxidative desulfurization evaluation experiment operation of the invention:

first, a simulated oil solution (sulfide is dibenzothiophene) with a sulfur concentration of 1000ppm was prepared, and then the W @ MZC series oxidative desulfurization catalyst prepared above, H, was used₂O₂(mass concentration is 30%) and a certain amount of methanol solution are uniformly mixed, the temperature condition is controlled to be 30-70 ℃, the reaction is carried out for 60min, an equal amount of oil phase and a methanol phase are taken, an upper oil phase is obtained by separation and analyzed, and the desulfurization rate is calculated.

The main evaluation indexes of the invention are as follows:

the desulfurization rate of the W @ MZC oxidative desulfurization catalyst on the mock oil (sulfide DBT) was analyzed and calculated using a gas chromatograph (model 3420A).

R＝[(C₀-C_t)/C₀]×100％

Wherein: desulfurization of R-mock oil,%; c₀-initial simulated sulphide concentration in oil, ppm; the Ct-concentration in oil, ppm, was simulated after the reaction.

The simulated oil used in the following examples was prepared using n-octane as the solvent and dibenzothiophene as the sulfur source, and had a sulfur content of 1000 ppm.

10mL of a mock oil, 10mL of methanol, 0.1g of the W @ MZC-80 type oxidative desulfurization catalyst obtained in example 13 above, and 134.7. mu.L of an aqueous hydrogen peroxide solution (with a mass concentration of 30% and an oxygen-sulfur ratio of 6) were charged into a three-necked flask, and after uniformly stirring at a certain temperature for 60 minutes, the mixture was centrifuged to separate layers; separating and removing the lower layer of methanol, analyzing the upper layer of oil product and calculating the desulfurization rate. The results of desulfurization rates at different reaction temperatures are shown in Table 1.

TABLE 1 Effect of reaction temperature on oxidative desulfurization Performance of catalyst

10mL of a mock oil, 10mL of methanol, 0.1g of the W @ MZC-80 type oxidative desulfurization catalyst obtained in example 13 above, and a predetermined amount of an aqueous hydrogen peroxide solution (30% by mass and 6% by oxygen-to-sulfur ratio) were charged into a three-necked flask, and after uniformly stirring at 60 ℃ for 60 minutes, the mixture was centrifuged to separate layers; separating and removing the lower layer of methanol, analyzing the upper layer of oil product and calculating the desulfurization rate. The results of the effect of different hydrogen peroxide addition amounts on the desulfurization performance of the catalyst are shown in table 2.

TABLE 2 Effect of hydrogen peroxide addition on oxidative desulfurization Performance of the catalyst

10mL of a mock oil, a predetermined amount of methanol, 0.1g of the W @ MZC-80 type oxidative desulfurization catalyst obtained in example 13 above, and 134.7. mu.L of an aqueous hydrogen peroxide solution (30% by mass and 6% by oxygen-to-sulfur ratio) were charged into a three-necked flask, and after uniformly stirring at 60 ℃ for 60 minutes, the mixture was centrifuged to separate layers; separating and removing the lower layer of methanol, analyzing the upper layer of oil product and calculating the desulfurization rate. The results of the effect of different methanol additions on the desulfurization performance of the catalyst are shown in Table 3.

TABLE 3 influence of different methanol additions on the desulfurization performance of the catalyst

The foregoing is only a preferred embodiment of the present invention and it should be understood that modifications and improvements may be made without departing from the principles of the invention and that such modifications and improvements are also considered within the scope of the invention.