Preparation and application of monatomic metal doped hydrophobic molybdenum disulfide catalyst

Abstract

The application discloses a preparation method and application of a single-atom metal-doped hydrophobic MoS2 catalyst. The single-atom metal-doped hydrophobic MoS2 catalyst is prepared by using a molybdenum-based ionic liquid as a precursor, in-situ sulfuration to obtain a molybdenum sulfide carrier, solvent thermal technology to dope the metal on the surface of the molybdenum sulfide carrier, and reduction treatment in a tube furnace. The catalyst exhibits excellent activity and stability in a hydrodeoxygenation reaction of biomass oil. The application provides an innovative and cost-effective preparation strategy of the single-atom metal-doped hydrophobic catalyst, opens up a new direction for industrial production and wide application of the catalyst, and helps to promote the development of a green chemical process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomass oil hydrodeoxygenation catalysts, and particularly relates to a preparation method and application of a single-atom metal-doped hydrophobic MoS2 catalyst. BACKGROUND

[0002] With the rapid development of global industrial economy and the continuous advancement of modernization, fossil energy such as oil, natural gas and coal is gradually depleted, and the ecological environment is deteriorating, especially the global greenhouse effect and acid rain phenomenon caused by exhaust gas after combustion of fossil fuels, which seriously threatens the sustainable development of human society and national energy security, and the development of green and environmentally friendly renewable new energy has attracted widespread attention worldwide.

[0003] Among numerous new energies, biomass oil can be an ideal new energy to replace fossil fuels. Biomass is widely studied and developed due to its characteristics of abundant resources, renewability and wide distribution, and has great application prospect. However, the unrefined biomass oil has a very high oxygen content, which can cause the performance of the biomass oil to deteriorate, such as low calorific value, strong corrosiveness and poor stability. Hydrodeoxygenation (HDO) is one of the effective means for refining biomass oil, which can convert oxygen-containing compounds into value-added chemicals and sustainable fuels, and has attracted widespread attention in the scientific community. Therefore, researchers have made a lot of research on the catalytic hydrodeoxygenation of biomass oil, and the core problem in the catalytic conversion technology of biomass oil is to design and construct an efficient, stable and inexpensive hydrodeoxygenation catalyst.

[0004] Commonly used hydrodeoxygenation catalysts, such as noble metal catalysts, often cause excessive hydrogenation of aromatic rings to generate byproducts, and the reaction conditions are harsh, which need to be carried out at high hydrogen pressure and high temperature, resulting in high hydrogen consumption, large energy loss and other problems, in addition, the noble metal is expensive, so such catalysts are difficult to be applied on a large scale; in addition, such as Ni, Co, Mo, W and their combination of sulfided state catalysts, although they have high hydrodeoxygenation performance, but the reaction stability is poor, and problems such as sulfur loss and carbon deposition will occur. Therefore, it is of great significance to develop an efficient, stable and inexpensive biomass oil hydrodeoxygenation catalyst. SUMMARY

[0005] In order to overcome the problems of stability, cost and synthesis complexity of the existing hydrodeoxygenation catalysts, the application provides an innovative preparation method and application strategy of a single-atom metal-doped hydrophobic MoS2 catalyst. The preparation method described in the application not only has a simple process, but also is convenient for large-scale production, and the prepared catalyst exhibits excellent activity and stability in the biomass oil hydrodeoxygenation reaction, which provides a reliable catalytic solution for efficient conversion of biomass oil.

[0006] In order to achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0007] A preparation method of a single-atom metal-doped hydrophobic MoS2 catalyst, comprising the following steps:

[0008] 1) In-situ sulfidation reaction of a molybdenum-based ionic liquid, sulfur powder and decalin in a reaction kettle, centrifugal washing after being cooled to room temperature, vacuum drying to constant weight, to obtain a MoS2 carrier;

[0009] 2) Doping reaction of a metal ionic liquid, decalin and the MoS2 carrier prepared in step 1) in a reaction kettle, centrifugal washing after being cooled to room temperature, vacuum drying to constant weight, reduction in a tube furnace, to obtain the single-atom metal-doped hydrophobic MoS2 catalyst.

[0010] Further, the molybdenum-based ionic liquid in step 1) is [N 8881 ]2MoO4, and the amount is converted to 1000 ppm-8000 ppm of Mo content in the system.

[0011] Further, the amount of sulfur powder in step 1) is converted to an S / Mo atomic ratio of 1-20 in the system.

[0012] Further, the temperature of the in-situ sulfidation reaction in step 1) is 180-360 ℃, the time is 0-36 h, and the hydrogen pressure is 0-8 MPa.

[0013] Further, the metal ionic liquid in step 2) is one or more of [N 8881 ]2CoCl4, [N 8881 ]FeCl4, [N 8881 ]2NiCl4, [N 8881 ]2CuCl4, [N 8881 ]2ZnCl4, [N 8881 ]2WO4.

[0014] Further, the amount of the metal ionic liquid in step 2) is converted to a molar ratio of 0-3 with respect to the metal atoms in the MoS2 carrier.

[0015] Further, the doping reaction in step 2) is carried out under normal pressure N2 atmosphere, the reaction temperature is 250-450 ℃, and the reaction time is 0-36 h.

[0016] Further, the reduction in step 2) is carried out in a mixed gas atmosphere of 10% H2 / 90% Ar, the reaction temperature is 150-800 ℃, and the reaction time is 1-10 h.

[0017] Further, the centrifugal speed in steps 1) and 2) is 5000-120000 r / min.

[0018] Further, the temperature of vacuum drying in steps 1) and 2) is 80-150 ℃, and the time is 6-24 h.

[0019] The monatomic metal-doped hydrophobic MoS2 catalyst prepared by the above method can be used for hydrodeoxygenation or hydrogenation reduction of one or more kinds of biomass oil, including lignin pyrolysis oil, biomass pyrolysis oil, biomass-based oxygen-containing compounds, and bio-oil.

[0020] Further, in the reaction, the mass ratio of the monatomic metal-doped hydrophobic MoS2 catalyst to the biomass oil used is 1-20%, the reaction hydrogen pressure is 0-10 MPa, the reaction temperature is 30-400 ℃, the reaction time is 0-36 h, and the hydrogen / oil ratio is 0-2000.

[0021] The technical scheme of the present application has the following advantages:

[0022] 1) The preparation process of the monatomic metal-doped hydrophobic MoS2 catalyst proposed in the present application uses metal ionic liquid as a precursor, which exhibits better uniform distribution characteristics than traditional metal sources, thus achieving high uniform dispersion of the metal and helping to reduce impurity generation. Based on the advantages of metal ionic liquid in structural controllability, it can effectively promote the strong interaction between the metal ions and the carrier, easily form a low coordination catalytic environment, and significantly improve the stability of the catalyst, which is crucial for improving the catalytic efficiency. In addition, as an oil-soluble precursor, metal ionic liquid can make the finally prepared catalyst have excellent hydrophobicity. The hydrophobic catalyst can effectively repel water molecules, reduce the competitive adsorption of water on the catalyst surface, and thus enhance the stability and activity of the catalyst. At the same time, this catalyst can also promote the adsorption of organic components in biomass oil on its surface, optimize the mass transfer process of reactants, reduce energy consumption and cost, achieve high purity and high yield of products, and thus enhance the economic value of biomass oil. Therefore, the present application successfully solves the key problems of existing monatomic metal-doped MoS2 catalysts in terms of insufficient stability and complex synthesis process, providing a highly efficient, high-stability, and cost-effective catalyst design scheme for the research and industrial communities. This breakthrough not only promotes the research progress of monatomic metal-doped hydrophobic MoS2 catalysts, but also provides a new technical approach for the hydrodeoxygenation process of biomass oil, which is expected to have a profound impact on the field of renewable energy conversion and fine chemical industry.

[0023] 2) The present application provides an innovative preparation process of single-atom metal-doped hydrophobic MoS2 catalyst, which selects decalin as the reaction solvent in the process of in-situ synthesis of single-atom catalyst. As an efficient organic solvent, decalin provides an ideal medium environment for the interaction between metal ion liquid and carrier, which promotes the effective combination between the two. In addition, the hydrophobic nature of decalin significantly enhances the hydrophobicity of single-atom catalyst, which is particularly advantageous for biomass oil hydrodeoxygenation (HDO) reaction. This hydrophobicity helps to reduce the competitive adsorption of water on the catalyst surface, thereby reducing the negative impact of water on catalytic activity. Therefore, the preparation process of the present application not only ensures the efficiency of the catalyst, but also improves its stability and selectivity in biomass oil HDO reaction.

[0024] 3) The single-atom metal-doped MoS2 catalyst prepared by the present application can achieve deep deoxygenation of different biomass oil products. Specifically, the single-atom metal-doped hydrophobic MoS catalyst prepared by the present application can selectively break the carbon-oxygen bonds of alcohol hydroxyl, phenolic hydroxyl, and fatty acids, fatty acid esters and glycerol acid esters, etc., so that the deoxygenation degree of biomass oil reaches more than 92%, and the selectivity of the target product reaches more than 90%. In addition, the structure of the single-atom metal-doped hydrophobic MoS2 catalyst has high designability, and can be applied to the hydrodeoxygenation process of different biomass oils. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 XRD pattern of the catalyst Co / MoS2 prepared in Example 2.

[0026] Figure 2 HAADF-STEM image and corresponding EDS element distribution map of the catalyst Co / MoS2 prepared in Example 2.

[0027] Figure 3 Air-water contact angle diagram of the catalyst Co / MoS2 prepared in Example 2. DETAILED DESCRIPTION

[0028] A preparation method of a single-atom metal-doped hydrophobic MoS2 catalyst, comprising the following steps:

[0029] 1) A certain amount of molybdenum-based ionic liquid [N 8881 ]2MoO4, sulfur powder and decalin are weighed in a high-pressure reaction kettle, and in-situ sulfuration is carried out at 180-360 ℃ and hydrogen pressure of 0-8 MPa for 0-36 h. After cooling to room temperature, centrifugal washing is carried out at 5000-120000 r / min, and vacuum drying is carried out at 80-150 ℃ for 6-24 h to constant weight, to obtain MoS2 carrier;

[0030] 2) A certain amount of metal ionic liquid, decalin and the MoS2 carrier prepared in step 1) are added into a high-pressure reaction kettle, and reacted at 250-450 °C for 0-36 h under normal pressure N2 atmosphere. After being cooled to room temperature, the sample is centrifuged and washed at 5000-120000 r / min, and vacuum dried at 80-150 °C for 6-24 h until the weight is constant. Then the sample is placed in a tube furnace, and reduced at 150-800 °C for 1-10 h in a mixed gas atmosphere of 10% H2 / 90% Ar, to prepare a single-atom metal-doped hydrophobic MoS2 catalyst.

[0031] In the formula, the amount of the molybdenum-based ionic liquid in step 1) is calculated according to the Mo content of 1000 ppm-8000 ppm in the system; and the amount of the sulfur powder is calculated according to the S / Mo atomic ratio of 1-20 in the system.

[0032] The metal ionic liquid in step 2) is one or more of [N 8881 ]2CoCl4, [N 8881 ]FeCl4, [N 8881 ]2NiCl4, [N 8881 ]2CuCl4, [N 8881 ]2ZnCl4, [N 8881 ]2WO4. The amount is calculated according to the molar ratio of the metal atom in the MoS2 carrier of 0-3.

[0033] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] The present application will be described in detail below through specific embodiments.

[0035] Example 1:

[0036] A single-atom metal-doped hydrophobic MoS2 catalyst Fe / MoS2 is prepared by the following steps:

[0037] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL high-pressure reactor, which was sealed, purged with high-purity hydrogen to replace the air in the reactor and pressurized to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the reactor was cooled to room temperature, the reaction liquid was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight to obtain a MoS2 carrier;

[0038] (2) 0.2617 g of [N 8881 ]FeCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL high-pressure reactor, which was sealed, purged with high-purity N2 to replace the air in the reactor and kept under normal pressure N2 atmosphere, and then heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the reactor was cooled to room temperature, the reaction liquid was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight; the dried sample was then placed in a tube furnace, purged with a mixed gas of 10% H2 / 90% Ar, and reduced at 400 °C for 2 h to obtain a target catalyst Fe / MoS2, wherein the molar ratio of Fe / Mo was 0.7.

[0039] The prepared catalyst Fe / MoS2 was used for selective deoxygenation of p-methylphenol, which specifically included weighing 0.0068 g of Fe / MoS2, 0.08 g of p-methylphenol and 2.2 g of dodecane, adding them into a 10 mL high-pressure reactor, sealing the reactor, purging the reactor with high-purity H2 to replace the air in the reactor and pressurizing to 4 MPa, and then heating to 300 °C at a rate of 5 °C / min, and reacting for 6 h. After the reactor was cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed using a gas chromatograph-mass spectrometer. The results showed that the degree of deoxygenation of p-methylphenol treated by Fe / MoS2 was 100%, and the selectivity of the main product toluene was 96.5%.

[0040] Example 2:

[0041] A single-atom metal-doped hydrophobic MoS2 catalyst Co / MoS2 was prepared, and the steps were as follows:

[0042] (1) 1.9205 g of ionic liquid [N 88812MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL high-pressure reactor, which was sealed, purged with high-purity hydrogen to replace the air in the reactor and pressurized to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the reactor was cooled to room temperature, the reaction solution was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight to obtain a MoS2 carrier;

[0043] (2) 0.1858 g of [N 8881 ]2CoCl4, 15 g decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL high-pressure reactor, which was sealed, purged with high-purity N2 to replace the air in the reactor and kept under normal pressure N2 atmosphere, and then heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the reactor was cooled to room temperature, the reaction solution was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight; the dried sample was then placed in a tube furnace, purged with a mixed gas of 10% H2 / 90% Ar, and reduced at 350 °C for 2 h to obtain a target catalyst Co / MoS2, wherein the Co / Mo molar ratio was 0.3.

[0044] The prepared catalyst Co / MoS2 was used for selective deoxygenation of nitrobenzene, specifically, 0.008 g of Co / MoS2, 0.06 g of nitrobenzene and 1.6 g of methanol were added into a 10 mL high-pressure reactor, which was sealed, purged with high-purity H2 to replace the air in the reactor and pressurized to 0.5 MPa, and then heated to 40 °C at a rate of 5 °C / min, and reacted for 5 h. After the reactor was cooled to room temperature, the reaction solution was filtered and separated, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed using a gas chromatograph-mass spectrometer. The results showed that the deoxygenation degree of nitrobenzene treated by Co / MoS2 was 100%, and the selectivity of the main product aniline was 100%.

[0045] Example 3:

[0046] A single-atom metal-doped hydrophobic MoS2 catalyst Ni / MoS2 was prepared, and the steps were as follows:

[0047] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL autoclave, which was sealed, purged with high-purity hydrogen to replace the air in the autoclave and pressurized to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight to obtain a MoS2 support;

[0048] (2) 0.1858 g of [N 8881 ]2NiCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 support were added into a 25 mL autoclave, which was sealed, purged with high-purity N2 to replace the air in the autoclave and kept under normal pressure N2 atmosphere, and then heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight; the dried sample was then placed in a tube furnace, purged with a mixed gas of 10% H2 / 90% Ar, and reduced at 400 °C for 3 h to obtain the target catalyst Ni / MoS2, wherein the molar ratio of Ni / Mo was 0.3.

[0049] The prepared catalyst Ni / MoS2 was used for selective deoxygenation of methyl palmitate, specifically, 0.03 g of Ni / MoS2, 0.5 g of methyl palmitate and 1.8 g of n-heptane were added into a 10 mL autoclave, which was sealed, purged with high-purity H2 to replace the air in the autoclave and pressurized to 5 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 8 h. After the autoclave was cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in ethyl acetate, and qualitative and quantitative analysis was performed using a gas chromatograph-mass spectrometer. The results showed that the degree of deoxygenation of methyl palmitate treated by Ni / MoS2 was 99.1%, and the selectivity of the product alkane was 95.2%.

[0050] Example 4:

[0051] A monatomic metal-doped hydrophobic MoS2 catalyst Zn / MoS2 was prepared, and the steps were as follows:

[0052] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g of decahydronaphthalene and 0.5 g of sulfur powder were added to a 100 mL high-pressure reactor, sealed, and high-purity hydrogen was introduced to replace the air in the reactor and pressurized to 4 MPa. The temperature was then raised to 280 °C at a rate of 5 °C / min and the reaction was carried out for 24 h. After the reactor cooled to room temperature, the reaction solution was placed in a centrifuge and centrifuged at 5000 r / min to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to obtain a constant weight to obtain a MoS2 carrier.

[0053] (2) Weigh 0.3118 g of [N 8881 ]2ZnCl4, 15 g decahydronaphthalene and 0.1056 g prepared MoS2 carrier were added to a 25 mL high-pressure reactor, sealed, and high-purity N2 was introduced to replace the air in the reactor while maintaining a normal pressure N2 atmosphere. The temperature was then raised to 320 °C at a rate of 5 °C / min and the reaction was carried out for 5 h. After the reactor cooled to room temperature, the reaction liquid was placed in a centrifuge and centrifuged at 5000 r / min to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight. The dried sample was then placed in a tubular furnace and introduced with a mixed gas of 10% H2 / 90% Ar and reduced at 300 °C for 4 h to obtain the target catalyst Zn / MoS2, wherein the Zn / Mo molar ratio was 0.5.

[0054] The prepared Zn / MoS2 catalyst was used for the selective deoxygenation of sunflower oil. Specifically, 0.1 g of Zn / MoS2 and 2.4 g of sunflower oil were added to a 10 mL autoclave, which was sealed. High-purity hydrogen was introduced to displace the air in the autoclave and the pressure was increased to 6 MPa. The autoclave was then heated to 350°C at a rate of 5°C / min and allowed to react for 10 h. After the autoclave cooled to room temperature, the reaction liquid was filtered and the residue was fully dissolved in methanol. Qualitative and quantitative analysis was performed using gas chromatography-mass spectrometry. Results showed that the deoxygenation degree of sunflower oil treated with Zn / MoS2 was 92.8%, and the selectivity for the main product, alkanes, was 95.1%.

[0055] Example 5:

[0056] A single-atom metal co-doped hydrophobic MoS2 catalyst Co-Fe / MoS2 is prepared, and the steps are as follows:

[0057] (1) Weigh 1.9205 g of ionic liquid [N 88812MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL autoclave, which was sealed, and high-purity hydrogen was introduced to replace the air in the autoclave and pressurize to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, and then placed in a vacuum drying oven, dried at 80 °C for 12 h to constant weight, to obtain a MoS2 carrier;

[0058] (2) 0.1239 g of [N 8881 ]2CoCl4, 0.1869 g of [N 8881 ]2FeCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL autoclave, which was sealed, and high-purity N2 was introduced to replace the air in the autoclave and maintain a normal pressure N2 atmosphere, and heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, and then placed in a vacuum drying oven, dried at 80 °C for 12 h to constant weight; and then the dried sample was placed in a tube furnace, and a mixed gas of 10% H2 / 90% Ar was introduced, and reduced at 400 °C for 2 h to obtain a target catalyst Co-Fe / MoS2, wherein the Co / Fe molar ratio was 0.4, and the (Co+Fe) / Mo molar ratio was 0.7.

[0059] The prepared catalyst Co-Fe / MoS2 was used for selective deoxygenation of p-methylphenol, which specifically was that 0.0068 g of Co-Ni / MoS2, 0.08 g of p-methylphenol and 2.2 g of dodecane were added into a 10 mL autoclave, which was sealed, and high-purity H2 was introduced to replace the air in the autoclave and pressurized to 4 MPa, and then heated to 180 °C at a rate of 5 °C / min, and reacted for 10 h. After the autoclave was cooled to room temperature, the reaction liquid was separated by filtration, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed by gas chromatography-mass spectrometry. The results showed that the deoxygenation degree of p-methylphenol treated by Co-Fe / MoS2 was 100%, and the selectivity of the main product toluene was 99.8%.

[0060] Example 6:

[0061] A single-atom metal co-doped hydrophobic MoS2 catalyst Co-Zn / MoS2 was prepared, and the steps were as follows:

[0062] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL autoclave, which was sealed, and high-purity hydrogen was introduced to replace the air in the autoclave and pressurize to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, and then placed in a vacuum drying oven, dried at 80 °C for 12 h to constant weight, to obtain a MoS2 carrier;

[0063] (2) 0.1858 g of [N 8881 ]2CoCl4, 0.0624 g of [N 8881 ]2ZnCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL autoclave, which was sealed, and high-purity N2 was introduced to replace the air in the autoclave and maintain a normal pressure N2 atmosphere, and then heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the autoclave was cooled to room temperature, the reaction liquid was placed in a centrifuge to centrifugal washing to obtain a solid sample, and then placed in a vacuum drying oven, dried at 80 °C for 12 h to constant weight; and then the dried sample was placed in a tube furnace, and a mixed gas of 10% H2 / 90% Ar was introduced, and reduced at 350 °C for 2 h to obtain a target catalyst Co-Zn / MoS2, wherein the molar ratio of Zn / Co is 0.3, and the molar ratio of (Co+Zn) / Mo is 0.4.

[0064] The prepared catalyst Co-Zn / MoS2 was used for selective deoxygenation of methyl palmitate, specifically, 0.01 g of Co-Zn / MoS2, 0.03 g of methyl palmitate and 3.0 g of decane were added into a 10 mL autoclave, which was sealed, and high-purity H2 was introduced to replace the air in the autoclave and pressurized to 4 MPa, and then heated to 240 °C at a rate of 5 °C / min, and reacted for 4 h. After the autoclave was cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in ethyl acetate, and qualitative and quantitative analysis was performed by gas chromatography-mass spectrometry. The results showed that the deoxygenation degree of methyl palmitate treated by Co-Zn / MoS2 was 100%, and the selectivity of the main product alkane was 95.6%.

[0065] Example 7:

[0066] A single-atom metal co-doped hydrophobic MoS2 catalyst Fe-Ni / MoS2 was prepared, and the steps were as follows:

[0067] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL high-pressure reactor, which was sealed, and high-purity hydrogen was introduced to replace the air in the reactor and pressurized to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the reactor was cooled to room temperature, the reaction liquid was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight, to obtain a MoS2 carrier;

[0068] (2) 0.0374 g of [N 8881 ]FeCl4, 0.1238 g of [N 8881 ]2NiCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL high-pressure reactor, which was sealed, and high-purity N2 was introduced to replace the air in the reactor and maintain a normal pressure N2 atmosphere, and then heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the reactor was cooled to room temperature, the reaction liquid was placed in a centrifuge for washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight; the dried sample was then placed in a tube furnace, and a mixed gas of 10% H2 / 90% Ar was introduced, and reduced at 450 °C for 2 h to obtain the target catalyst Fe-Ni / MoS2, wherein the molar ratio of Ni / Fe is 0.5, and the molar ratio of (Fe+Ni) / Mo is 0.3.

[0069] The prepared catalyst Fe-Ni / MoS2 was used for selective deoxygenation of lignin pyrolysis oil, which specifically included weighing 0.03 g of Fe-Ni / MoS2, 0.08 g of lignin pyrolysis oil and 2.2 g of dodecane, adding them into a 10 mL high-pressure reactor, which was sealed, and high-purity H2 was introduced to replace the air in the reactor and pressurized to 4 MPa, and then heated to 200 °C at a rate of 5 °C / min, and reacted for 8 h. After the reactor was cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed using a gas chromatograph-mass spectrometer. The results showed that the deoxygenation degree of the lignin pyrolysis oil treated by Fe-Ni / MoS2 was 100%.

[0070] Example 8:

[0071] A single-atom metal co-doped hydrophobic MoS2 catalyst Cu-Zn / MoS2 was prepared, and the steps were as follows:

[0072] (1) 1.9205 g of ionic liquid [N 8881]2MoO4, 30 g decalin and 0.3405 g sulfur powder were added into a 100 mL autoclave, which was sealed, purged with high-purity hydrogen to replace the air in the autoclave and pressurized to 4 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 24 h; after the autoclave was cooled to room temperature, the reaction solution was placed in a centrifuge for centrifugal washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight, to obtain a MoS2 carrier;

[0073] (2) 0.0622 g of [N 8881 ]2CuCl4, 0.0624 g of [N 8881 ]2ZnCl4, 15 g of decalin and 0.1056 g of the prepared MoS2 carrier were added into a 25 mL autoclave, which was sealed, purged with high-purity N2 to replace the air in the autoclave and kept in a normal-pressure N2 atmosphere, heated to 320 °C at a rate of 5 °C / min, and reacted for 5 h; after the autoclave was cooled to room temperature, the reaction solution was placed in a centrifuge for centrifugal washing to obtain a solid sample, which was then placed in a vacuum drying oven and dried at 80 °C for 12 h to constant weight; the dried sample was then placed in a tube furnace, purged with a mixed gas of 10% H2 / 90% Ar, and reduced at 300 °C for 3 h to obtain a target catalyst Cu-Zn / MoS2, wherein the Cu / Zn molar ratio was 1 and the (Cu+Zn) / Mo molar ratio was 0.2.

[0074] The prepared catalyst Cu-Zn / MoS2 was used for selective deoxygenation of waste oil, specifically, 0.05 g of Cu-Zn / MoS2, 0.08 g of waste oil and 2.2 g of dodecane were added into a 10 mL autoclave, which was sealed, purged with high-purity H2 to replace the air in the autoclave and pressurized to 5 MPa, and then heated to 280 °C at a rate of 5 °C / min, and reacted for 12 h. After the autoclave was cooled to room temperature, the reaction solution was filtered and separated, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed by gas chromatography-mass spectrometry. The results showed that the deoxygenation degree of the waste oil treated by Cu-Zn / MoS2 was 97.6%, and the selectivity of alkanes was 92.3%.

[0075] Comparative Example 1:

[0076] 0.1858 g of [N 8881 ]2CoCl4 in step (2) of Example 2 was replaced with 0.0351 g of cobalt acetate, and the remaining operations were the same as in Example 2, to finally obtain a Co 1 / MoS2 catalyst, wherein the Co / Mo molar ratio was 0.3.

[0077] The prepared catalyst Co1 Co / MoS2 for the selective deoxygenation of nitrobenzene, specifically, 0.008 g of Co 1 / MoS2, 0.06 g of nitrobenzene and 1.6 g of methanol were added into a 10 mL high-pressure reactor, which was sealed, purged with high-purity H2 to replace the air in the reactor, and pressurized to 0.5 MPa, and then heated to 40 °C at a rate of 5 °C / min, and reacted for 5 h. After the reactor was cooled to room temperature, the reaction solution was separated by filtration, and the filter residue was fully dissolved in methanol, and qualitative and quantitative analysis was performed using a gas chromatograph-mass spectrometer. The results showed that the degree of deoxygenation of nitrobenzene treated by Co 1 / MoS2 was 19%, and the selectivity of the main product aniline was 97%.

[0078] Comparative Example 2:

[0079] 0.1858 g of [N 8881 ]2CoCl4 in step (2) of Example 2 was replaced with 0.0257 g of CoCl2, and the rest of the operations were the same as in Example 2, and finally a Co 2 / MoS2 catalyst was obtained, in which the Co / Mo molar ratio was 0.3.

[0080] The prepared catalyst Co 2 / MoS2 was used for the selective deoxygenation of nitrobenzene, specifically, 0.008 g of Co 2 / MoS2 treated nitrobenzene was 8%, and the selectivity of the main product aniline was 100%.

[0081] Comparative Example 3:

[0082] The reaction solvent decalin used in Example 2 was replaced with an equal volume of dodecane, and the rest of the operations were the same as in Example 2, and finally a Co 3 / MoS2 catalyst was obtained.

[0083] The prepared catalyst Co 3 / MoS2 was used for the selective deoxygenation of nitrobenzene, specifically, 0.008 g of Co 3 / MoS2, 0.06 g nitrobenzene and 1.6 g methanol were added to a 10 mL autoclave, sealed, and high-purity H2 was introduced to replace the air in the autoclave and pressurized to 0.5 MPa. The temperature was then raised to 40 °C at a rate of 5 °C / min and the reaction was continued for 5 h. After the autoclave cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in methanol and qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry. The results showed that the presence of Co 3 The deoxygenation degree of nitrobenzene treated with / MoS2 is 78%, and the selectivity of the main product aniline is 85%.

[0084] Comparative Example 4:

[0085] The reaction solvent decalin used in Example 2 was replaced with an equal volume of cyclohexane, and the remaining operations were the same as in Example 2 to finally obtain Co 4 / MoS2 catalyst.

[0086] The prepared catalyst Co 4 / MoS2 was used for the selective deoxidation of nitrobenzene, specifically 0.008 g of Co 3 / MoS2, 0.06 g nitrobenzene and 1.6 g methanol were added to a 10 mL autoclave, sealed, and high-purity H2 was introduced to replace the air in the autoclave and pressurized to 0.5 MPa. The temperature was then raised to 40 °C at a rate of 5 °C / min and the reaction was continued for 5 h. After the autoclave cooled to room temperature, the reaction liquid was filtered and separated, and the filter residue was fully dissolved in methanol and qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry. The results showed that the presence of Co 4 The deoxygenation degree of nitrobenzene treated with / MoS2 is 90%, and the selectivity of the main product aniline is 95%.

[0087] The above results show that the catalyst prepared by the method of the present invention has high biomass oil hydrodeoxygenation activity, can realize the biomass oil hydrodeoxygenation process under mild conditions, its deoxygenation rate is close to 100%, and the yield of the main product is as high as more than 90%, among which Example 2 has the best effect.

[0088] The Co-MoS2 catalyst prepared in Example 2 was subjected to XRD analysis, and the results were as follows: Figure 1 shown. Figure 1 It shows that the diffraction peaks at 13.2°, 33.5°, and 58.9° can be attributed to the (002), (101), and (110) crystal planes of MoS2 (JCPDS No. 37-1492), respectively, while no characteristic diffraction peaks related to the doped metal Co are found, which indicates that the metal dispersion is relatively uniform.

[0089] Through in-depth analysis of Comparative Examples 1 and 2 and Example 2, it can be found that the catalyst prepared by using the metal ionic liquid as the precursor has excellent performance, especially in terms of conversion rate and selectivity. This is because the metal ionic liquid not only promotes the strong interaction between the metal ions and the carrier, but also promotes the uniform dispersion of the metal ions on the surface of the carrier, which effectively reduces the generation of impurities. In addition, this uniform dispersion provides favorable conditions for the formation of a low-coordination single-atom catalyst structure, which is crucial for the improvement of catalyst activity. The HAADF-STEM image of the Co / MoS2 catalyst prepared according to Example 2 and its corresponding EDS element distribution map Figure 2 ) can clearly observe that the Co element is uniformly dispersed in the form of single atoms on the MoS2 carrier. This result shows that, in the in-situ synthesis process with the metal ionic liquid as the precursor, Co atoms successfully anchor on the surface of MoS2 in the form of single atoms without forming larger agglomerates or nanoparticles. This single-atom dispersion state is the ideal form pursued in catalyst design, as it can maximize the catalytic activity of metal atoms, while reducing the amount of metal used, improving catalytic efficiency and selectivity.

[0090] The results of Comparative Examples 3 and 4 and Example 2 show that, in the application of hydrodeoxygenation, the catalyst prepared using decalin as the solvent exhibits better performance. This advantage can be partially attributed to the high solubility of the metal ionic liquid as an oil-soluble precursor in decalin, which helps to ensure the uniform dispersion of the precursor and the subsequent uniform formation of the catalyst. In addition, the hydrophobic nature of decalin is particularly advantageous in the preparation of hydrophobic catalysts, as it helps to form a hydrophobic layer on the surface of the catalyst, which is very important for catalytic reactions that require the exclusion of water, such as the hydrodeoxygenation of biomass oil (the presence of water can interfere with the catalytic reaction, reducing the activity and selectivity of the catalyst, while a hydrophobic surface can effectively reduce this interference). In order to verify the hydrophobicity of the catalyst, the air-water contact angle of the Co / MoS2 catalyst prepared according to Example 2 was measured, and the results are shown in Figure 3 The results in the figure show that the air-water contact angle of the catalyst reaches 108.9°, demonstrating its excellent hydrophobicity. This result not only shows that the method of the present application can successfully prepare a highly hydrophobic catalyst, but also provides an efficient catalytic scheme for the hydrodeoxygenation of biomass oil.

[0091] The unmentioned parts of the present application apply to the prior art.

[0092] Obviously, the above embodiments are merely example for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments need not and can not be enumerated. The obvious changes or variations derived from the above description are still within the protection scope of the present application.

Claims

1. A method for preparing a monatomic metal-doped hydrophobic MoS2 catalyst, characterized in that, The method comprises the following steps: 1) in-situ sulfidation reaction of molybdenum-based ionic liquid, sulfur powder and decalin in a reaction kettle, centrifugal washing after being cooled to room temperature, vacuum drying to constant weight, and preparation of MoS2 carrier; 2) doping reaction of metal ionic liquid, decalin and MoS2 carrier prepared in step 1) in a reaction kettle, centrifugal washing after being cooled to room temperature, vacuum drying to constant weight, reduction in a tube furnace, and preparation of the single-atom metal-doped hydrophobic MoS2 catalyst. The molybdenum-based ionic liquid in step 1) is [N 8881 ]2MoO4; the amount is converted to Mo content of 1000 ppm to 8000 ppm in the system. The metal ionic liquid in step 2) is one or more of [N 8881 ]2CoCl4, [N 8881 ]FeCl4, [N 8881 ]2NiCl4, [N 8881 ]2CuCl4, [N 8881 ]2ZnCl4, [N 8881 ]2WO4; the amount is converted to the molar ratio of metal atoms in the MoS2 carrier of 0.2-3.

2. The method for preparing a single-atom metal-doped hydrophobic MoS2 catalyst according to claim 1, wherein: The amount of sulfur powder in step 1) is converted according to the S / Mo atomic ratio in the system of 1-20.

3. The method for preparing a single-atom metal-doped hydrophobic MoS2 catalyst according to claim 1, wherein: The temperature of the in-situ sulfidation reaction in step 1) is 180-360 ℃, the time is 0-36 h, and the hydrogen pressure is 0-8 MPa.

4. The method for preparing a single-atom metal-doped hydrophobic MoS2 catalyst according to claim 1, wherein: The doping reaction in step 2) is carried out under normal pressure N2 atmosphere, the reaction temperature is 250-450 ℃, and the reaction time is 0-36 h.

5. The method for preparing a single-atom metal-doped hydrophobic MoS2 catalyst according to claim 1, wherein: The reduction in step 2) is carried out in a mixed gas atmosphere of 10% H2 / 90% Ar, the reaction temperature is 150-800 ℃, and the reaction time is 1-10 h.

6. Application of the single-atom metal-doped hydrophobic MoS2 catalyst prepared by the method of claim 1 in a biomass oil hydrodeoxygenation reaction.

7. Use according to claim 6, characterized in that, The biomass oil comprises one or more of lignin pyrolysis oil, biomass pyrolysis oil, biomass-based oxygen-containing compound and bio-oil.

8. Use according to claim 6, characterized in that, In the reaction, the mass ratio of the single-atom metal-doped hydrophobic MoS2 catalyst to the biomass oil used is 1-20%, the reaction hydrogen pressure is 0-10 MPa, the reaction temperature is 30-400 ℃, the reaction time is 0-36 h, and the hydrogen / oil ratio is 0-2000.

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