Carbon intercalation molybdenum disulfide nanohollow sphere catalyst and preparation and application thereof

Abstract

The application discloses a carbon intercalation molybdenum disulfide nanometer hollow sphere catalyst and a preparation and application thereof, wherein the nanometer hollow sphere has a particle size of 100-300 nm, a wall thickness of 30-80 nm, an inner diameter of the internal hollow chamber of 40-160 nm, and a specific surface area of 70-100 m 2 / g; the hollow sphere is self-assembled by carbon intercalation molybdenum disulfide nanometer sheets. The carbon intercalation molybdenum disulfide nanometer hollow sphere catalyst prepared by the application can fully expose the catalytic hydrogenation active sites of molybdenum disulfide, has high catalytic hydrogenation activity, has good suspensibility and dispersibility in a slurry bed residual oil hydrogenation reaction system, and can still maintain good structural stability under high-temperature and high-pressure conditions. The raw material used in the preparation method is cheap and easy to obtain, the operation is simple and controllable, and the method is easy to realize large-scale industrial application.

Description

Technical Field

[0001] This invention relates to a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst, its preparation and application, and belongs to the field of catalyst preparation. Technical Background

[0002] Global energy demand is constantly growing, and fossil fuels are the primary source to meet this demand. As one of the three major fossil fuels, oil is increasingly shifting towards heavier fuels due to the declining supply of conventional light crude oil. Converting heavy oil into high-value-added light products is crucial to meeting the oil consumption needs of industries such as transportation and chemicals, which consume large quantities of oil. (See J. Catal., 2013, 308, 189) In heavy oil hydroconversion processes, slurry-bed hydroconversion has advantages such as a wide range of feedstocks that can be processed, good coking suppression, and high conversion efficiency. Molybdenum disulfide is a commonly used catalyst in slurry-bed heavy oil hydroconversion processes, characterized by high dispersibility and high hydrogenation activity. (See J. Ind. Eng. Chem., 2019, 76, 1)

[0003] Molybdenum disulfide (MoD) is a typical two-dimensional layered transition metal sulfide, with monolayers of MoD bonded together by relatively weak van der Waals forces. Each layer of MoD has an S-Mo-S "sandwich" structure, meaning two layers of sulfur atoms sandwich a layer of molybdenum atoms, with each molybdenum atom covalently bonded to six sulfur atoms. MoD exists in three crystalline phases: 1T, 2H, and 3R, with the 2H phase being the most stable, where the molybdenum atoms are triangular prisms with six-coordinate arrangements. Due to its unique layered structure and physicochemical properties, MoD has numerous applications in catalysis, energy storage, and semiconductor manufacturing. (See Chem. Soc. Rev., 2015, 44, 2603)

[0004] Because molybdenum disulfide nanosheets tend to agglomerate into solid particles under high temperature and pressure conditions, making it difficult to expose many catalytically active sites, those skilled in the art have developed various methods for preparing hollow molybdenum disulfide materials. CN201710397526.1 discloses a method for preparing hollow spherical molybdenum disulfide / carbon composite materials. This method uses silica microspheres as templates, grows molybdenum disulfide and carbon on the surface, and finally etches away the silica microspheres with an alkaline solution to obtain hollow microspheres of molybdenum disulfide / composite material. CN201911311522.2 discloses a hollow sandwich layered structure molybdenum disulfide-based nanocomposite material and its preparation method. This method sequentially coats a carbon layer, a molybdenum disulfide layer, and a carbon layer onto a silica template, and then etches the silica to prepare a hollow sandwich layered structure molybdenum disulfide-based nanocomposite material. CN201711481492.0 discloses a method for preparing a polyacrylonitrile / molybdenum disulfide composite material for supercapacitors. This method first uses PMMA as a template to form a hollow spherical structure of PAN with uniform macropores, and then grows molybdenum disulfide nanoflowers on the PAN surface to obtain the hollow composite material. CN201810883455.0 discloses a method for preparing a molybdenum disulfide composite hollow carbon nanofiber material. This method first prepares polyphosphazene hollow nanofibers, and then grows a layer of molybdenum disulfide nanosheets in situ on their surface to obtain the composite material. CN201810458809.7 discloses a flower-shaped hollow molybdenum disulfide / nitrogen-rich carbon composite material and its preparation method. This method uses melamine resin microspheres as a carbon source, grows molybdenum disulfide nanosheets in situ on the surface of the microspheres, and then pyrolyzes them under a nitrogen atmosphere to obtain the hollow composite material. CN201710683148.3 discloses a method for preparing a molybdenum disulfide-coated titanium dioxide hollow core-shell composite photocatalyst and its application. The method involves in-situ growth of molybdenum disulfide on the surface of hollow titanium dioxide to obtain the material.

[0005] In the aforementioned methods for preparing hollow molybdenum disulfide materials, to construct the hollow structure, it is often necessary to grow molybdenum disulfide in situ on a hollow template, or to grow molybdenum disulfide in situ on a non-hollow template before etching the template. The problems with these methods are: the crystallization reaction of molybdenum disulfide is uneven, with only a portion of the molybdenum disulfide growing on the template surface; the molybdenum disulfide that does not combine with the template is prone to self-aggregation; the structure of the synthesized hollow molybdenum disulfide material depends on the template structure, and the controllable range is limited; and the etching conditions of the template are difficult to control, causing damage to the hollow structure of the molybdenum disulfide itself. Summary of the Invention

[0006] To address the aforementioned problems, the improved method of this invention employs a one-step solution method, mixing a sulfur source, a molybdenum source, and a carbon source into a homogeneous solution. Under hydrothermal reaction conditions, carbon-intercalated molybdenum disulfide nanosheets are uniformly crystallized and grown. Without the need for template addition or etching, the carbon-intercalated molybdenum disulfide nanosheets can self-assemble into hollow nanosphere structures. By changing the carbon-to-molybdenum ratio, the structure of the carbon-intercalated molybdenum disulfide nanosheets is controlled, thereby regulating the size and structure of the hollow nanospheres. The carbon-intercalated molybdenum disulfide hollow nanosphere structure increases the specific surface area of ​​molybdenum disulfide, exposing more catalytic active sites. Since the density of carbon is less than that of molybdenum disulfide, and the density of the hollow sphere structure is also less than that of solid particles, the carbon-intercalated molybdenum disulfide hollow nanosphere structure can significantly reduce the bulk density of the catalyst, improving its suspension and dispersibility in the slurry-bed heavy oil hydrogenation reaction system. The carbon source is carbonized between the molybdenum disulfide layers, which ensures that the catalyst maintains good structural stability under the high temperature and high pressure conditions of the hydrogenation reaction system.

[0007] This invention provides a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. The hollow nanospheres have a particle size of 100–300 nm, a wall thickness of 30–80 nm, an inner diameter of 40–160 nm for the internal hollow chambers, and a specific surface area of ​​70–100 m². 2 The hollow sphere, per g, is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. Each nanosheet has a thickness of 3–8 nm, with the distance between the two furthest points on any side surface ranging from 10–30 nm. Each nanosheet contains 3–7 layers of stacked plate-like molybdenum disulfide, each layer being 0.65–0.67 nm thick. Amorphous carbon forms the spaces between the plate-like molybdenum disulfide layers, with carbon comprising 0.1%–37% of the catalyst by mass. This structure increases the specific surface area of ​​molybdenum disulfide, fully exposing its catalytically active sites, while simultaneously reducing the catalyst's bulk density, improving its suspension and dispersibility in slurry-bed heavy oil hydrogenation reaction systems, and maintaining the catalyst's structural stability under high temperature and high pressure conditions.

[0008] This invention also provides a method for preparing carbon-intercalated molybdenum disulfide hollow nanosphere catalysts, comprising the following steps:

[0009] (1) At least one of ammonium heptamolybdate, sodium molybdate, and phosphomolybdic acid is used as a molybdenum source, at least one of thiourea, thioacetamide, ammonium thiocyanate, glutathione, and L-cysteine ​​is used as a sulfur source, and at least one of glucose, fructose, galactose, maltose, sucrose, and lactose is used as a carbon source. The molar ratio of Mo, S, and C is 1-2:5:0.1-30 in deionized water, wherein the molar ratio of C to Mo of the carbon source and the molybdenum source is 0.05-30. After thorough stirring, a transparent mixed solution is formed.

[0010] (2) Transfer the above mixed solution to a hydrothermal reactor, microwave reactor, or oil bath heated flask and crystallize at 120-200°C for 3-72 hours.

[0011] (3) A black product is obtained by one of the separation methods such as filtration, vacuum filtration, centrifugation, or sedimentation. The product is then calcined in nitrogen, argon, or helium at 300–800 °C for 1–24 h to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst.

[0012] The carbon-intercalated molybdenum disulfide nanosphere catalyst prepared by the above method can be used for the hydrotreating of slurry bed residue to produce gasoline and / or diesel. The composition range of the vacuum residue used in the experiment is 15%–50% saturated fraction, 20%–55% aromatic fraction, 20%–50% gum, and 1%–15% asphaltenes. The catalyst content (calculated as MoS2) in the reaction system is 0.01 wt.%–0.3 wt.%; the reaction temperature is 300–500℃; and the initial hydrogen pressure is 12–20 MPa.

[0013] This invention discloses a catalyst preparation method that mixes a sulfur source, a molybdenum source, and a carbon source into a homogeneous solution. Under hydrothermal reaction conditions, carbon-intercalated molybdenum disulfide nanosheets are uniformly crystallized and grown. Without the addition or etching of a template, the carbon-intercalated molybdenum disulfide nanosheets can self-assemble into hollow nanosphere structures. By changing the carbon-to-molybdenum ratio, the structure of the carbon-intercalated molybdenum disulfide nanosheets can be controlled, thereby regulating the size and structure of the hollow nanospheres. This preparation method uses inexpensive and readily available raw materials, is simple and controllable, offers a wide range of structural control over the catalyst, and is easily applicable to large-scale industrial applications.

[0014] The structural characterization and analysis of the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst prepared in this invention are as follows: Figure 1 As shown in the XRD patterns, compared with the 2H-MoS2 standard card, both the pure molybdenum disulfide synthesized under the same conditions in the comparative example and the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst of this invention are in the 2H-MoS2 phase. However, the (002) crystal plane diffraction peak of molybdenum disulfide in the catalyst of this invention has basically disappeared, indicating that molybdenum disulfide has a single-layer or few-layer structure, and also indicating that the size of molybdenum disulfide nanosheets is small. At the same time, the catalyst of this invention shows two new diffraction peaks at 8.1° and 16.1°. According to the Bragg equation calculation results, their interplanar spacings are 1.1 nm and 0.55 nm, respectively, which can be attributed to the interlayer spacing of molybdenum disulfide and the interlayer spacing between molybdenum disulfide and carbon nanomaterials, respectively. This indicates that carbon has entered the interlayer intercalation of molybdenum disulfide. Figure 2 SEM images show that the catalyst has a surface morphology of nanospheres with a clearly broken hollow structure. Figure 3TEM images show that the catalyst is indeed a hollow nanosphere structure, which is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The hollow sphere structure increases the specific surface area of ​​molybdenum disulfide, fully exposing its catalytic hydrogenation active sites, which is beneficial to improving the hydrogenation activity and stability of the catalyst. The thickness of a single nanosheet is 3-6 nm, and the distance between the two furthest points on any side surface is 10-26 nm. The nanosheet contains 3-5 layers of stacked plate-like molybdenum disulfide, with amorphous carbon between the plate-like molybdenum disulfide layers. Figure 4 SEM images show that the surface morphology of pure molybdenum disulfide in Comparative Example 1 consists of microspheres assembled from relatively large nanosheets, exhibiting severe agglomeration and making it difficult to expose catalytic hydrogenation active sites. Adding a carbon source to synthesize molybdenum disulfide can reduce the catalyst particle size from the micrometer scale to the nanometer scale and construct a hollow nanosphere structure, increasing the particle specific surface area from 12.5 m² / s². 2 / g increased to 100.7m 2 / g.

[0015] Compared with existing technologies, this invention has the following advantages and effects: Existing methods for preparing hollow molybdenum disulfide materials often require in-situ growth of molybdenum disulfide on a hollow template, or in-situ growth of molybdenum disulfide on a non-hollow template followed by template etching. The method of this invention directly utilizes carbon-intercalated molybdenum disulfide nanosheets to self-assemble into hollow nanosphere structures. Methodologically, this invention does not require the addition or etching of additional templates, making the synthesis process simpler and the conditions easier to control. In terms of material properties, the addition of carbon materials can further reduce the bulk density of the hollow sphere structure and improve its stability.

[0016] This invention provides a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. The hollow nanospheres have a particle size of 100–300 nm, a wall thickness of 30–80 nm, an inner diameter of 40–160 nm for the internal hollow chambers, and a specific surface area of ​​70–100 m². 2 / g, this hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. Each nanosheet is 3–8 nm thick, and the distance between the two furthest points on any side surface is 10–30 nm. The nanosheets contain 3–7 layers of stacked plate-like molybdenum disulfide, each layer being 0.65–0.67 nm thick; the interlayers of the plate-like molybdenum disulfide are filled with amorphous carbon, with a carbon content of 0.1%–37% by mass in the catalyst. The carbon-intercalated molybdenum disulfide hollow nanosphere structure can increase the specific surface area of ​​molybdenum disulfide from 12.5 m² / g. 2 / g increased to 100.7m 2 / g, exposing more catalytic active sites in molybdenum disulfide; since the density of carbon is less than that of molybdenum disulfide, and the density of hollow spheres is also less than that of solid particles, the carbon-intercalated molybdenum disulfide nano-hollow sphere structure can significantly reduce the bulk density of the catalyst and improve its suspension and dispersibility in the slurry bed heavy oil hydrogenation reaction system; the carbon source is carbonized in the interlayer of molybdenum disulfide, which enables the catalyst to maintain structural stability under the high temperature and high pressure conditions of the hydrogenation reaction system.

[0017] The catalyst preparation method provided by this invention involves mixing a sulfur source, a molybdenum source, and a carbon source into a homogeneous solution, and then uniformly crystallizing and growing carbon-intercalated molybdenum disulfide nanosheets under hydrothermal reaction conditions. Without the need for template addition or etching, the carbon-intercalated molybdenum disulfide nanosheets can self-assemble into hollow nanosphere structures. By changing the carbon-to-molybdenum ratio, the structure of the carbon-intercalated molybdenum disulfide nanosheets can be controlled, thereby regulating the size and structure of the hollow nanospheres. The raw materials used in this preparation method are inexpensive and readily available, the operation is simple and controllable, and it is easy to achieve large-scale industrial application.

[0018] The carbon-intercalated molybdenum disulfide hollow nanosphere catalyst prepared by this invention can fully expose the catalytic hydrogenation active sites of molybdenum disulfide, exhibiting high catalytic hydrogenation activity. It also demonstrates good suspension and dispersibility in slurry bed residue oil hydrogenation reaction systems and maintains good structural stability under high temperature and high pressure conditions. Attached Figure Description

[0019] Figure 1 The XRD pattern of the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst in Example 1 is shown below.

[0020] Figure 2 Here is a SEM image of the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst from Example 1;

[0021] Figure 3 This is a TEM image of the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst from Example 1.

[0022] Figure 4 This is a SEM image of the molybdenum sulfide microsphere catalyst in Comparative Example 2. Detailed Implementation

[0023] The present invention will be further described below with reference to implementation examples, but this does not limit the scope of the present invention.

[0024] Example 1

[0025] 1.1 g of ammonium heptamolybdate, 2.37 g of thioacetamide, and 2.80 g of glucose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a hydrothermal reactor and crystallized in an oven at 200 °C for 3 h. The reaction product was separated by filtration and washed three times with deionized water to obtain a black product. This product was calcined in a tube furnace under a nitrogen atmosphere at 800 °C for 1 h to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. The specific surface area of ​​the obtained catalyst was 76.9 m². 2 / g, Figure 2 The hollow spheres of the catalyst shown have a particle size of 283–300 nm. Figure 3 The hollow sphere shown has a wall thickness of 71–80 nm and an inner diameter of 127–142 nm for its internal hollow chamber. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. Each nanosheet has a thickness of 3.5–6 nm and contains 3–5 layers of stacked plate-like molybdenum disulfide, each layer being 0.65 nm thick. The distance between the two furthest points on any side surface of the nanosheets is 10–26 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the carbon content in the catalyst is 25% by mass.

[0026] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The reaction was carried out under the following conditions: 30 g of vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gums) as feedstock; 0.2 wt.% of catalyst (based on MoS2) in the reaction system; 500℃; and an initial hydrogen pressure of 20 MPa for 4 h. The catalytic activity evaluation results are shown in Table 1.

[0027] Example 2

[0028] 2.2 g of ammonium heptamolybdate, 2.37 g of thiourea, and 0.0374 g of maltose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a hydrothermal reactor and crystallized in an oven at 180 °C for 12 h. The product after reaction was filtered, washed three times with deionized water to obtain a black product, which was calcined in a tube furnace at 600 °C for 2 h under a nitrogen atmosphere to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. XRD and HRTEM analysis showed that its structure was the same as that of the product in Example 1, except that the hollow spheres of the obtained catalyst had a particle size of 261–278 nm, a wall thickness of 53–68 nm, and a specific surface area of ​​80.7 m². 2 / g. The inner diameter of the hollow chamber is 125–152 nm. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The thickness of each individual nanosheet is 3–8 nm, containing 3–7 layers of stacked plate-like molybdenum disulfide, each layer being 0.65 nm thick. The distance between the two furthest points on any side surface of the nanosheet is 13–30 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the mass content of carbon in the catalyst is 0.2%.

[0029] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gum), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, and the reaction was carried out at a temperature of 450 °C and an initial hydrogen pressure of 16 MPa for 4 h. The catalytic activity evaluation results are shown in Table 1.

[0030] Example 3

[0031] 0.96 g of phosphomolybdic acid, 9.57 g of glutathione, and 0.0187 g of fructose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a polytetrafluoroethylene-lined reactor and crystallized at 140 °C for 24 h in a microwave reactor. The product after reaction was centrifuged and washed three times with deionized water to obtain a black product, which was calcined at 700 °C for 2 h in an argon atmosphere in a tube furnace to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. XRD and HRTEM analysis showed that its structure was the same as that of the product in Example 1, except that the hollow spheres of the obtained catalyst had a particle size of 228–239 nm, a wall thickness of 50–56 nm, and a specific surface area of ​​77.5 m². 2 / g. The inner diameter of the hollow chamber is 116–137 nm. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The thickness of each individual nanosheet is 5–8 nm, containing 5–7 layers of stacked plate-like molybdenum disulfide, each layer being 0.66 nm thick. The distance between the two furthest points on any side surface of the nanosheets is 17–30 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the carbon content in the catalyst is 0.1% by mass.

[0032] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gum), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 450℃, and the initial hydrogen pressure was 14 MPa, with a reaction time of 4 h. The catalytic activity evaluation results are shown in Table 1.

[0033] Example 4

[0034] 1.92 g of phosphomolybdic acid, 3.18 g of L-cysteine, and 0.187 g of sucrose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a polytetrafluoroethylene-lined reactor and crystallized at 160 °C for 24 h in a microwave reactor. The product after reaction was separated by sedimentation and washed three times with deionized water to obtain a black product. This product was calcined at 500 °C for 12 h in an argon atmosphere in a tube furnace to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. XRD and HRTEM analysis showed that its structure was the same as that of the product in Example 1, except that the hollow spheres of the obtained catalyst had a particle size of 100–112 nm, a wall thickness of 30–34 nm, and a specific surface area of ​​100.3 m². 2 / g. The inner diameter of the hollow chamber is 40–48 nm. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The nanosheets composing the hollow sphere are 3–6 nm thick and contain 3–5 layers of stacked plate-like molybdenum disulfide, each layer being 0.65 nm thick. The distance between the two furthest points on any side surface of the nanosheets is 10–23 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the carbon content in the catalyst is 1% by mass.

[0035] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gum), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 400℃, and the initial hydrogen pressure was 14 MPa, with a reaction time of 4 h. The catalytic activity evaluation results are shown in Table 1.

[0036] Example 5

[0037] 1.51 g of sodium molybdate, 2.37 g of ammonium thiocyanate, and 2.80 g of galactose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a flask heated in an oil bath and crystallized at 120 °C for 72 h. The product after reaction was separated by vacuum filtration and washed three times with deionized water to obtain a black product. This product was calcined in a tube furnace at 500 °C for 12 h under a helium atmosphere to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. XRD and HRTEM analysis showed that its structure was the same as that of the product in Example 1, except that the hollow spheres of the obtained catalyst had a particle size of 127–135 nm, a wall thickness of 38–47 nm, and a specific surface area of ​​88.55 m². 2 / g. The inner diameter of the hollow chamber is 47–55 nm. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The nanosheets composing the hollow sphere are 3.5–6 nm thick and contain 3–5 layers of stacked plate-like molybdenum disulfide, each layer being 0.67 nm thick. The distance between the two furthest points on any side surface of the nanosheets is 12–18 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the carbon content in the catalyst is 24% by mass.

[0038] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated fractions, 50.00% aromatics, and 25.01% gums), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 350 °C, and the initial hydrogen pressure was 12 MPa, with a reaction time of 4 h. The catalytic activity evaluation results are shown in Table 1.

[0039] Example 6

[0040] 3.02 g of sodium molybdate, 2.37 g of thioacetamide, and 5.6 g of lactose were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a flask heated in an oil bath and crystallized at 180 °C for 24 h. The product after reaction was separated by suction filtration and washed three times with deionized water to obtain a black product. This product was calcined in a tube furnace under a helium atmosphere at 300 °C for 24 h to obtain a carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. XRD and HRTEM analysis showed that its structure was the same as that of the product in Example 1, except that the hollow spheres of the obtained catalyst had a particle size of 203–218 nm, a wall thickness of 58–65 nm, and a specific surface area of ​​70.7 m². 2 / g. The inner diameter of the hollow chamber is 77–88 nm. This hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets. The nanosheets composing the hollow sphere are 3–6 nm thick and contain 3–5 layers of stacked plate-like molybdenum disulfide, each layer being 0.65 nm thick. The distance between the two furthest points on any side surface of the nanosheets is 10–15 nm. Amorphous carbon is present between the plate-like molybdenum disulfide layers, and the carbon content in the catalyst is 37% by mass.

[0041] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated fractions, 50.00% aromatics, and 25.01% gums), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 300℃, and the initial hydrogen pressure was 14 MPa for 4 h. The catalytic activity evaluation results are shown in Table 1.

[0042] Comparative Example 1

[0043] 1.1 g of ammonium heptamolybdate and 2.37 g of thiourea were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. The mixed solution was transferred to a hydrothermal reactor and crystallized in an oven at 200 °C for 12 h. The product after reaction was separated by vacuum filtration and washed three times with deionized water to obtain a black product, which was calcined in a tube furnace at 600 °C for 2 h under a nitrogen atmosphere to obtain molybdenum disulfide microsphere catalyst. Figure 1 The XRD pattern shows that the molybdenum disulfide nanosheets that make up the catalyst have an interlayer spacing of 0.65 nm. Figure 4 SEM images show that the obtained microsphere catalyst has a particle size of 2–2.5 μm and a specific surface area of ​​12.5 m². 2 / g.

[0044] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gum), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 500℃, and the initial hydrogen pressure was 20 MPa, with a reaction time of 4 h. The catalytic activity evaluation results are shown in Table 1.

[0045] Comparative Example 2

[0046] 1.1 g of ammonium heptamolybdate and 2.37 g of thiourea were dissolved in 60 mL of deionized water and stirred thoroughly for 30 minutes to form a transparent solution. Amorphous carbon powder obtained from the hydrothermal carbonization of sucrose was added to the solution and stirred until homogeneous, forming a suspension. The suspension was transferred to a hydrothermal reactor and crystallized in an oven at 200 °C for 12 h. The product was separated by filtration and washed three times with deionized water to obtain a black product, which was calcined in a tube furnace under a nitrogen atmosphere at 600 °C for 2 h to obtain an amorphous carbon-supported molybdenum disulfide microsphere catalyst. The obtained microsphere catalyst had a particle size of 2–2.5 μm, with molybdenum disulfide nanosheets supported on the surface of the amorphous carbon spheres to form a core-shell structure. The core particle size was 1.8–2.2 μm, the shell thickness was 100–150 nm, and the specific surface area was 3.85 m². 2 / g.

[0047] The obtained catalyst was used in a slurry bed residue hydrotreating reaction. The feedstock, vacuum residue (containing 5.02% asphaltenes, 19.97% saturated matter, 50.00% aromatics, and 25.01% gum), was used in an amount of 30 g. The catalyst (calculated as MoS2) content in the reaction system was 0.2 wt.%, the reaction temperature was 500℃, and the initial hydrogen pressure was 20 MPa, with a reaction time of 4 h. The catalytic activity evaluation results are shown in Table 1.

[0048] Table 1 Catalytic hydrogenation activity of the catalyst prepared in this invention and the comparative catalyst.

[0049]

[0050] The carbon-intercalated molybdenum disulfide hollow nanosphere catalyst prepared by this invention can fully expose the catalytic hydrogenation active sites of molybdenum disulfide, exhibiting high catalytic hydrogenation activity. It demonstrates good suspension and dispersibility in slurry-bed residue hydrogenation reaction systems and maintains good structural stability even under high temperature and high pressure conditions. The raw materials used in this preparation method are inexpensive and readily available, the operation is simple and controllable, and it is easy to achieve large-scale industrial application.

Claims

1. A carbon-intercalated molybdenum disulfide hollow nanosphere catalyst, characterized in that, The catalyst has hollow nanospheres with a particle size of 100-300 nm, a wall thickness of 30-80 nm, an inner diameter of 40-160 nm for the internal hollow chambers, and a specific surface area of ​​70-100 m². 2 / g, the hollow sphere is self-assembled from carbon-intercalated molybdenum disulfide nanosheets; the thickness of a single nanosheet is 3~8nm, the distance between the two furthest points on any side surface is 10~30nm, and a single nanosheet contains 3~7 layers of stacked plate-like molybdenum disulfide, each layer of molybdenum disulfide is 0.65nm~0.67nm thick; the interlayers of plate-like molybdenum disulfide are amorphous carbon, and the mass content of carbon in the catalyst is 0.1%~37%; A method for preparing carbon-intercalated molybdenum disulfide hollow nanosphere catalysts includes the following steps: (1) Dissolve the molybdenum source, sulfur source and carbon source in water at a molar ratio of Mo, S and C of 1~2:5:1~10, and stir thoroughly to form a transparent precursor solution; (2) The above transparent precursor solution was crystallized at 180~200℃ for 12~24h. (3) Solid products were obtained by solid-liquid separation, calcined in an inert gas, and cooled to obtain carbon-intercalated molybdenum disulfide hollow nanosphere catalysts. The molybdenum source mentioned in step (1) is one or a mixture of two or more of ammonium heptamolybdate, sodium molybdate, and phosphomolybdic acid; The sulfur source is one or a mixture of two or more of thiourea, thioacetamide, ammonium thiocyanate, glutathione, and L-cysteine; The carbon source is one or a mixture of two or more of glucose, fructose, galactose, maltose, sucrose, and lactose.

2. A method for preparing the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst according to claim 1, characterized in that, Includes the following steps: (1) Dissolve the molybdenum source, sulfur source and carbon source in water at a molar ratio of Mo, S and C of 1~2:5:1~10, and stir thoroughly to form a transparent precursor solution; (2) The above transparent precursor solution was crystallized at 180~200℃ for 12~24h; (3) Solid product was obtained by solid-liquid separation, calcined in an inert gas, and cooled to obtain carbon-intercalated molybdenum disulfide hollow nanosphere catalyst. The molybdenum source mentioned in step (1) is one or a mixture of two or more of ammonium heptamolybdate, sodium molybdate, and phosphomolybdic acid; The sulfur source is one or a mixture of two or more of thiourea, thioacetamide, ammonium thiocyanate, glutathione, and L-cysteine; The carbon source is one or a mixture of two or more of glucose, fructose, galactose, maltose, sucrose, and lactose.

3. The preparation method according to claim 2, characterized in that, In step (2), the crystallization reaction is carried out in a hydrothermal reactor, a microwave reactor, or a flask heated in an oil bath.

4. The preparation method according to claim 2, characterized in that: In step (3), the solid-liquid separation method is one of filtration, centrifugation, or sedimentation.

5. The preparation method according to claim 2, characterized in that: In step (3), the inert gas is one or more of nitrogen, argon, and helium, the calcination temperature is 300~800℃, and the calcination time is 1~24h.

6. The preparation method according to claim 5, characterized in that: In step (3), the roasting temperature is 500~600℃ and the roasting time is 2~8h.

7. The application of the carbon-intercalated molybdenum disulfide hollow nanosphere catalyst of claim 1 in the catalytic hydrogenation reaction of residual oil.

8. The application according to claim 7, characterized in that: The catalyst is used for the hydrotreating of vacuum residue in a slurry bed to produce gasoline and / or diesel. The composition of the vacuum residue ranges from 15% to 50% saturated matter, 20% to 55% aromatic matter, 20% to 50% gum and 1% to 15% asphaltenes. The catalyst content in the system, calculated as MoS2, is 0.01 wt.%~0.3 wt.%, the reaction temperature is 300~500℃, and the initial hydrogen pressure is 12~20 MPa.

9. The application according to claim 8, characterized in that: The catalyst content in the system, calculated as MoS2, is 0.1 wt.%~0.2 wt.%; the reaction temperature is 400~450℃; and the initial hydrogen pressure is 14~18 MPa.

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