A modified bimetallic catalyst, its preparation method and application

Abstract

The application relates to the technical field of catalysts, and discloses a modified bimetallic catalyst and a preparation method and application thereof, the preparation method of the modified bimetallic catalyst comprises the following steps: adding a niobium compound, a template agent, a titanium compound and carbon balls into a solvent to obtain a mixed solution; then adding an amino precipitate into the mixed solution to carry out reaction, and obtaining a crude product after calcination; then reacting the crude product with an amino modification solution, and obtaining the product after drying; on the one hand, the titanium compound is added to modify the niobium-based catalyst, chemical action occurs between the two kinds of metals, and the catalytic activity is enhanced; on the other hand, the hollow porous catalyst is prepared by using the double-template combination and the hydrothermal method, transmission channels are provided for macromolecular sulfides, and the adsorption and diffusion processes in the pore channel are accelerated; meanwhile, after the amino modification, the catalyst surface is rich in amino groups and the hydroxyl group polarity is enhanced, the catalyst can directly adsorb the sulfone substances generated in the desulfurization process, and low-temperature and high-efficiency desulfurization is realized.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a modified bimetallic catalyst, its preparation method, and its application. Background Technology

[0002] To effectively control the environmental pollution caused by sulfur compounds in fuel oil, the production of ultra-low sulfur fuel oil has become a major research topic. Among existing desulfurization technologies, hydrodesulfurization is widely used in the petrochemical industry. However, as the number of cycloalkane and aromatic rings in crude oil sulfur compounds increases, the reactivity of hydrogenation decreases. Dibenzothiophene, containing three rings, is particularly difficult to desulfurize via hydrodesulfurization; furthermore, hydrodesulfurization requires harsh process conditions, large amounts of hydrogen, and high production costs. In non-hydrodesulfurization technologies, single adsorption and extraction desulfurization have low efficiency, while catalytic oxidation desulfurization technology has attracted widespread attention due to its high desulfurization efficiency and mild reaction conditions. Traditional catalytic oxidation desulfurization technology utilizes the synergistic effect of catalysts and oxidants to oxidize organic sulfur compounds such as dibenzothiophene in fuel oil into highly polar sulfones, which are then extracted with polar extractants such as methanol to achieve deep desulfurization.

[0003] Transition metal oxides possess advantages such as high catalytic efficiency, strong stability, and easy separation and recovery. For example, Nb₂O₅ is a typical non-toxic solid oxide with abundant active and defect sites, strong redox capabilities, and unique Lewis acid sites (L-acids) and Brønsted acid sites (B-acids). It has attracted widespread attention and been applied in catalytic oxidation desulfurization materials. However, most existing niobium-based catalysts suffer from problems such as large particle size, small specific surface area, small pore size, and weak surface polarity. This leads to the need for large amounts of oxidant, long reaction times, high temperatures, and the reliance on extractants to achieve ideal desulfurization performance, thus affecting their further applications. Therefore, how to further modify and enhance their catalytic performance is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0004] In view of this, the present invention provides a method for preparing a modified bimetallic desulfurization catalyst to improve the desulfurization activity of fuel oil oxidation.

[0005] The present invention also provides a modified bimetallic desulfurization catalyst prepared by the above method.

[0006] The present invention also provides an application of the above-mentioned catalyst in fuel oil oxidative desulfurization.

[0007] On one hand, the present invention provides a method for preparing a modified bimetallic desulfurization catalyst, comprising the following steps:

[0008] (1) Niobium compound, template agent, titanium compound and carbon balls are added to solvent to obtain a mixture;

[0009] (2) The mixture is added to an amino precipitate solution and reacted, then calcined to obtain a crude product;

[0010] (3) React the crude product with the amino-modified solution.

[0011] In one optional embodiment, the amino-modified liquid comprises at least one of 3-aminopropyltrihexyloxysilane, 3-aminopropyltrimethoxysilane, and diethylenetriaminopropyltrimethoxysilane.

[0012] In one optional embodiment, the mass ratio of the crude product to the volume ratio of the amino-modified solution is 1:0.2-0.3, with a ratio of g / mL.

[0013] In one optional embodiment, the amino precipitate is an aqueous solution of an amino precipitant.

[0014] In one alternative embodiment, the amino precipitant includes at least one of urea, ammonium bicarbonate, and ammonia.

[0015] In one optional embodiment, the concentration of the amino precipitate is 2-2.5 mol / L.

[0016] In one alternative embodiment, the niobium compound includes at least one of niobium pentachloride, ammonium niobate oxalate hydrate, and niobium ethoxide, preferably ammonium niobate oxalate hydrate.

[0017] In one optional embodiment, the titanium compound includes at least one of titanium tetrachloride, titanium trichloride, butyl titanate, and tetrabutyl titanate, preferably titanium tetrachloride.

[0018] In one optional embodiment, the template agent includes at least one of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123) and polyoxyethylene polyoxypropylene ether triblock copolymer (F127), preferably P123.

[0019] In one optional embodiment, the solvent includes at least one of anhydrous ethanol, deionized water, toluene, and xylene.

[0020] In one optional embodiment, the ratio of the niobium compound, template agent, carbon balls, solvent and amino precipitant is 100g: 50-200g: 5-15g: 1000-3000mL: 1400-1500mL.

[0021] In one optional embodiment, the niobium compound and titanium compound are calculated based on niobium and titanium elements, respectively, and the molar ratio of niobium and titanium elements is 100:3-10.

[0022] In one optional embodiment, in step (1), the particle size of the carbon balls is 5-50 nm.

[0023] In one optional embodiment, the mixing temperature is 40-50°C and the time is 20-40 minutes.

[0024] In an optional embodiment, the method further includes an alkali activation treatment step for the carbon balls, specifically: dispersing the carbon balls in the amino precipitate solution, reacting at 45-55℃ for 10-14 hours, and obtaining the final product after filtration and drying; the mass ratio of the carbon balls to the volume of the amino precipitate solution is 5:15-30, with a ratio of g / mL.

[0025] In one optional embodiment, in step (2), the reaction temperature is 90-110°C and the reaction time is 8-12h.

[0026] In one optional embodiment, step (2) further includes a stirring step before the reaction, wherein the stirring temperature is 40-50°C and the stirring time is 10-14h.

[0027] In one optional embodiment, in step (2), the mixed solution is added by ultrasonic atomization spraying.

[0028] In one optional embodiment, during the calcination step, the mixture is heated to 700-800°C at a heating rate of 3-7°C / min and calcined for 4-5 hours.

[0029] In an optional embodiment, step (3) further includes an organic solvent, wherein the organic solvent is at least one of toluene, xylene, and ethanol.

[0030] In one optional embodiment, the mass ratio of the crude product to the volume ratio of the organic solvent is 1:90-110, with a ratio of g / mL.

[0031] In one optional embodiment, in step (3), the reaction temperature is 100-110°C and the time is 22-26h.

[0032] In one optional embodiment, in step (3), the reaction is carried out under a nitrogen atmosphere with a nitrogen flow rate of 50-300 mL / min, preferably 200 mL / min.

[0033] In one optional embodiment, step (3) further includes a drying step after the reaction is completed, wherein the drying temperature is 100-110°C and the drying time is 8-12 hours.

[0034] Secondly, the present invention provides a modified bimetallic desulfurization catalyst, which is prepared by the above-described preparation method.

[0035] Thirdly, the present invention provides an application of the above-mentioned modified bimetallic desulfurization catalyst in fuel oil oxidative desulfurization.

[0036] Fourthly, the present invention provides a fuel oil desulfurization method, comprising the following steps: a reaction is carried out in the presence of the above-mentioned desulfurization catalyst and oxidant.

[0037] In one alternative embodiment, the oxidant is hydrogen peroxide.

[0038] In one alternative embodiment, the sulfur content in the fuel is 100-500 ppm.

[0039] In one alternative embodiment, the reaction temperature is 30-60°C.

[0040] In one alternative embodiment, as the amount of template agent increases, the particle size gradually increases, which has a significant impact on the quantity and quality of nanopores. When P123 is used alone and the amount is too large, the mesoporous structure is prone to collapse, thereby reducing the specific surface area and pore volume of the catalyst. Carbon spheres can support the mesoporous structure to prevent structural collapse after the polymer template agent is removed, which is beneficial to forming a bimetallic catalyst with high specific surface area and large pore size.

[0041] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0042] 1. The present invention provides a method for preparing a modified bimetallic catalyst, comprising the following steps: (1) adding niobium compound, template agent, titanium compound and carbon balls to a solvent and stirring to obtain a mixed solution; (2) adding amino precipitate to the mixed solution for reaction, and obtaining a crude product after calcination; (3) reacting the crude product with amino modification solution and drying to obtain the catalyst. In the present invention, niobium ions will be hydrolyzed to generate niobic acid. The addition of amino precipitate is to promote the hydrolysis of metal ions. Combined with the hydrothermal process, as the low-boiling-point solvent evaporates, a solid substance is formed to coat the outer layer of the carbon balls, forming a shell structure. During the calcination process, the carbon balls and template agent are removed, and the shell solid substance is gradually oxidized and decomposed. Accompanied by the shrinkage of the shell structure (to reduce surface tension), the pore size, specific surface area and pore volume of the catalyst can be greatly improved, and a hollow porous bimetallic catalyst is finally obtained.

[0043] This invention, based on niobium-based catalysts, modifies niobium pentoxide by adding titanium compounds. The strong chemical interaction between the two metals enhances its catalytic activity. Specifically, on the one hand, it alters the Nb... 5+The high electron cloud density in the vicinity induces a phase transition in Nb₂O₅, transforming it from an orthorhombic phase to a hexagonal phase after high-temperature calcination. This increases the defect structure of niobium pentoxide, and these defect sites have high reactivity, capable of adsorbing and activating reactant molecules and promoting the reaction, thus enhancing the catalytic oxidation desulfurization activity. On the other hand, titanium compounds and Nb₂O₅, as catalyst substrates, possess unique Lewis acid sites and redox capabilities, which are beneficial for mass transfer and catalytic oxidation reactions. Specifically, the sulfur atoms in thiophene molecules contain lone pairs of electrons, and the Lewis acid sites can attack the lone pairs of electrons on the sulfur atoms, thus fixing the thiophene by the catalyst, which is beneficial for the desulfurization reaction. Niobium ions and titanium ions have high valence, strong redox capabilities, and high positive charges, allowing sulfur atoms to directly form SM bonds with metal atoms M to adsorb thiophene substances.

[0044] In addition, this invention utilizes a dual-template combined with a hydrothermal method to prepare a catalyst with a hollow porous structure, increasing the specific surface area and pore volume of the catalyst and forming a hollow structure. This provides ample transport channels for macromolecular sulfides, accelerating their adsorption and diffusion processes within the pores. This also results in more exposed active sites on the catalyst and higher catalytic activity.

[0045] Meanwhile, the present invention utilizes amino modification to make the catalyst surface rich in amino groups and enhance the polarity of hydroxyl groups, which can directly adsorb sulfone substances such as dibenzothiophene sulfone (DBTO2) and dibenzothiophene sulfoxide generated during the desulfurization process, and can achieve low-temperature and high-efficiency desulfurization without the use of other extractants or adsorbents.

[0046] 2. The present invention provides a method for preparing a modified bimetallic catalyst, which further includes alkali activation treatment of the carbon spheres. Specifically, the carbon spheres are dispersed in an amino precipitate solution for reaction, thereby expanding the pores on the surface of the carbon spheres, thereby increasing the surface area and improving the adsorption capacity; at the same time, it is beneficial to the adsorption of niobium ions and effectively forming a hollow niobium pentoxide shell.

[0047] 3. This invention provides a method for preparing a modified bimetallic catalyst, in which a mixed solution is added to an amino precipitant with the assistance of an ultrasonic atomizing nozzle, which helps to reduce particle agglomeration.

[0048] 4. This invention provides a method for preparing a modified bimetallic catalyst, wherein the reaction time of the mixed solution and the amino precipitate is controlled to be 8-12 h, which is beneficial to the growth of the niobium shell on the surface of the carbon spheres.

[0049] 5. This invention provides a method for preparing a modified bimetallic catalyst. By limiting the molar ratio of niobium and titanium to 100:3-10, the ratio of niobium pentoxide in orthorhombic and hexagonal crystal phases, structural defects, pore volume, pore size, and specific surface area can be controlled, thereby further improving the catalyst activity.

[0050] 6. This invention provides an application of a modified bimetallic desulfurization catalyst in fuel oxidative desulfurization, which can achieve low-temperature and efficient removal of dibenzothiophene sulfur-containing compounds from fuel in the presence of an oxidant, and achieve deep desulfurization without the use of an extractant; the catalyst has mild reaction conditions, stable structure and properties, and good recyclability, and can effectively remove large molecular sulfur compounds such as DBT, 4-MDBT and 4,6-DMDBT from fuel. Attached Figure Description

[0051] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1 These are SEM images of the catalyst prepared in Example 1 of this invention, wherein (a) is an SEM image of the outer surface and (b) is an SEM image of the inner surface.

[0053] Figure 2 These are the wide-angle XRD patterns of the catalysts prepared in Examples 1, 2 and Comparative Example 1 of this invention.

[0054] Figure 3 These are wide-angle XRD magnified images of the catalysts prepared in Examples 1, 2 and Comparative Example 1 of this invention.

[0055] Figure 4 This is the XPS full spectrum of the catalyst prepared in Example 1 of this invention.

[0056] Figure 5 These are fine XPS elemental spectra of the catalysts prepared according to the present invention; wherein, (a) is the fine N elemental spectrum of TiNbOx (5:100) prepared in Example 1, (b) is the fine Nb elemental spectrum of TiNbOx (5:100) prepared in Example 1 and Nb2O5 prepared in Comparative Example 1, (c) is the fine O elemental spectrum of TiNbOx (5:100) prepared in Example 1, and (d) is the fine Ti elemental spectrum of TiNbOx (5:100) prepared in Example 1 and TiO2 prepared in Comparative Example 2.

[0057] Figure 6 This is a test of the desulfurization activity of the catalysts prepared in Examples 1-3 and Comparative Examples 1-4 of this invention on simulated oil.

[0058] Figure 7 This is a test of the desulfurization activity of the catalyst prepared in Example 1 of the present invention at different temperatures.

[0059] Figure 8 The images show the catalyst cycle performance test (a) prepared in Example 1 of this invention and the XRD comparison spectrum (b) of the fresh catalyst and the catalyst after 10 cycles. Detailed Implementation

[0060] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0061] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0062] To address the problems existing in the aforementioned related technologies, according to a first aspect of the present invention, the present invention provides a method for preparing a modified bimetallic catalyst, comprising the following steps: (1) adding a niobium compound, a template agent, a titanium compound, and carbon spheres to a solvent and stirring to obtain a mixed solution; (2) adding an amino precipitate to the mixed solution for reaction, and calcining to obtain a crude product; (3) reacting the crude product with an amino-modifying solution, and drying to obtain the catalyst. The catalyst prepared by the present invention has a hollow porous structure, which can greatly improve the pore size, specific surface area, and pore volume of the catalyst. Based on the niobium-based catalyst, the present invention adds a titanium compound to modify niobium pentoxide, resulting in a strong chemical interaction between the two metals, enhancing its catalytic activity. Specifically, on the one hand, it modifies the Nb... 5+ The density of electron clouds in the vicinity induces a phase transition in Nb2O5, transforming it from an orthorhombic phase to a hexagonal phase after high-temperature calcination. This increases the defect structure of niobium pentoxide and enhances its catalytic oxidation desulfurization activity. On the other hand, titanium compounds and Nb2O5, as catalyst substrates, possess unique Lewis acid sites and redox capabilities. The number of Lewis acid centers is closely related to the conversion rate of sulfides such as 4,6-dimethyldibenzothiophene (4,6-DMDBT), which is beneficial for mass transfer and catalytic oxidation reactions.

[0063] In addition, the present invention utilizes a dual-template combined with a hydrothermal method to prepare a catalyst with a hollow porous structure, which provides abundant transport channels for the transport of macromolecular sulfides, accelerating their adsorption and diffusion processes within the pores. This also results in the catalyst having more exposed active sites and higher catalytic activity.

[0064] Meanwhile, the present invention utilizes amino modification to make the catalyst surface rich in amino groups and enhance the polarity of hydroxyl groups, which can directly adsorb sulfone substances such as dibenzothiophene sulfone (DBTO2) and dibenzothiophene sulfoxide generated during the desulfurization process, and can achieve low-temperature and high-efficiency desulfurization without the use of other extractants or adsorbents.

[0065] The present invention will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention.

[0066] In this invention, P123 and F127 were both purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Ammonium niobate oxalate hydrate was also purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a molecular weight of 302.98.

[0067] Example 1

[0068] This embodiment provides a method for preparing a modified bimetallic catalyst, comprising the following steps:

[0069] (1) Weigh 2g of ammonium niobate oxalate hydrate (C4H4NNbO9·nH2O), 0.0625g of TiCl4, 2g of P123, and 0.1g of carbon balls activated by surface alkali and add them to 30mL of anhydrous ethanol. Stir at 45℃ for 30min to obtain a mixed solution.

[0070] The preparation process of surface alkali activated carbon balls is as follows: 5g of carbon balls with a pore size of 5-50nm are dispersed in 15mL of 2mol / L ammonia solution, and the mixture is stirred and reacted in a water bath at 50℃ for 12h. After filtration and drying, the carbon balls are obtained.

[0071] (2) The mixed solution obtained in step (1) was added to 30 mL of 2 mol / L ammonia water through an ultrasonic atomizing sprayer. After stirring at 45 °C for 12 h, it was hydrothermally reacted at 100 °C for 12 h. The reaction product was collected, washed and dried, and then placed in a muffle furnace and calcined at 800 °C for 4 h at a heating rate of 5 °C / min to remove the template agent, and the crude product was obtained.

[0072] (3) 1g of the crude solid product was ultrasonically dispersed in 100mL of toluene, and 0.25mL of 3-aminopropyltrihexyloxysilane (APTES) was added. The mixture was refluxed at 110℃ under a nitrogen atmosphere (flow rate of 200mL / min) for 24h. After reflux, the suspension was filtered, and the resulting pale yellow solid was washed with distilled water and dried at 110℃ for 12h to obtain TiNbOx (5:100).

[0073] Example 2

[0074] This embodiment provides a method for preparing a modified bimetallic catalyst, which is basically the same as the steps in Example 1, except that in step (1), the mass of titanium tetrachloride (TiCl4) added is 0.125g, and the resulting catalyst is named TiNbOx (10:100).

[0075] Example 3

[0076] This embodiment provides a method for preparing a modified bimetallic catalyst, which is basically the same as the steps in Example 1, except that in step (1), the mass of titanium tetrachloride (TiCl4) added is 0.038g, and the resulting catalyst is named TiNbOx (3:100).

[0077] Example 4

[0078] This embodiment provides a method for preparing a modified bimetallic catalyst, comprising the following steps:

[0079] (1) Weigh 2g of niobium pentachloride, 0.1g of tetrabutyl titanate, 1g of F127 and 0.3g of carbon balls activated by surface alkali and add them to 20mL of toluene. Stir at 40℃ for 40min to obtain a mixed solution.

[0080] The preparation process of surface alkali activated carbon balls is as follows: 5g of carbon balls with a pore size of 5-50nm are dispersed in 30mL of 2.5mol / L ammonium bicarbonate solution, and the mixture is stirred at a constant temperature of 45℃ for 14h. After filtration and drying, the carbon balls are obtained.

[0081] (2) The mixed solution obtained in step (1) was added to 28 mL of 2.5 mol / L urea solution through an ultrasonic atomizing sprayer. After stirring at 40 °C for 14 h, the mixture was hydrothermally reacted at 110 °C for 8 h. The reaction product was collected, washed and dried, and then placed in a muffle furnace and calcined at 750 °C for 4.5 h at a heating rate of 3 °C / min to remove the template agent, thus obtaining the crude product.

[0082] (3) 1g of the crude solid product was ultrasonically dispersed in 90mL of xylene, and 0.2mL of 3-aminopropyltrimethoxysilane (APES) was added. The mixture was refluxed at 100℃ under a nitrogen atmosphere (flow rate of 300mL / min) for 26h. After reflux, the suspension was filtered, and the resulting pale yellow solid was washed with distilled water and dried at 105℃ for 8h to obtain TiNbOx (4:100).

[0083] Example 5

[0084] This embodiment provides a method for preparing a modified bimetallic catalyst, comprising the following steps:

[0085] (1) Weigh 2g of niobium ethanol, 0.08g of TiCl3, 4g of P123, and 0.2g of carbon balls activated by surface alkali and add them to 60mL of deionized water. Stir at 50℃ for 20min to obtain a mixed solution.

[0086] The preparation process of surface alkali activated carbon balls is as follows: 5g of carbon balls with a pore size of 5-50nm are dispersed in 20mL of 2.25mol / L urea solution, and the mixture is stirred at a constant temperature of 55℃ for 10h. After filtration and drying, the carbon balls are obtained.

[0087] (2) The mixed solution obtained in step (1) was added to 29 mL of 2.25 mol / L ammonium bicarbonate solution through an ultrasonic atomizing sprayer. After stirring at 50 °C for 10 h, the mixture was hydrothermally reacted at 90 °C for 10 h. The reaction product was collected, washed and dried, and then placed in a muffle furnace and calcined at 7 °C / min to 700 °C for 5 h to remove the template agent, thus obtaining the crude product.

[0088] (3) 1g of solid crude product was ultrasonically dispersed in 110mL of ethanol, and 0.3mL of diethylenetriaminepropyltrimethylsilane (NQ-62) was added. The mixture was refluxed at 105℃ under a nitrogen atmosphere (flow rate of 50mL / min) for 22h. After reflux, the suspension was filtered, and the resulting pale yellow solid was washed with distilled water and dried at 100℃ for 10h to obtain TiNbOx (8.25:100).

[0089] Comparative Example 1

[0090] This comparative example provides a method for preparing a catalyst, which is basically the same as the steps in Example 1, except that in step (1), TiCl4 is replaced with ammonium niobate oxalate hydrate, and the resulting catalyst is named Nb2O5.

[0091] Comparative Example 2

[0092] This comparative example provides a method for preparing a catalyst, which is basically the same as the steps in Example 1, except that in step (1), ammonium niobate oxalate hydrate is replaced with 2g TiCl4, and the resulting catalyst is named TiO2.

[0093] Comparative Example 3

[0094] This comparative example provides a method for preparing a catalyst, which is basically the same as the steps in Example 1, except that the addition of 3-aminopropyltrihexyloxysilane (APTES) is omitted in step (3), and the resulting material is named TiNbOx(5:100)-non-amino modified.

[0095] Comparative Example 4

[0096] This comparative example provides a method for preparing a catalyst, which is basically the same as the steps in Example 1, except that in step (1), TiCl4 is replaced with ZrCl4, and the resulting catalyst is named ZrNbOx (5:100).

[0097] Experimental Example 1

[0098] The catalyst prepared in Example 1 was subjected to SEM testing, and the results are as follows: Figure 1 As shown, from Figure 1 (a) It can be seen that the prepared TiNbOx(5:100) microspheres have a hollow structure, from Figure 1 (b) It can be seen that the prepared TiNbOx(5:100) microspheres have a porous structure.

[0099] XRD tests were performed on the catalysts prepared in Examples 1, 2, and Comparative Example 1. PDF#28-0317 is the standard PDF card for the hexagonal niobium pentoxide phase, and PDF#30-0873 is the standard PDF card for the orthorhombic niobium pentoxide phase. Results are shown in […]. Figure 2 As shown, Comparative Example 1 exhibits nine distinct characteristic peaks at 2θ = 22.606°, 28.586°, 36.711°, 46.233°, 50.673°, 55.186°, 56.139°, 58.969°, and 63.783°. Compared with the standard PDF card (PDF#30-0873), it can be seen that the catalyst prepared in Comparative Example 1 is an orthorhombic niobium pentoxide. Similarly, no characteristic peaks of titanium oxide (27.443°, 36.098°, 54.338°, etc.) were detected in the catalysts prepared in Examples 1 and 2, indicating that titanium doping has entered the niobium pentoxide lattice but has not formed an independent crystalline phase.

[0100] Figure 3The images shown are magnified wide-angle XRD patterns at 2θ = 40-70° for the catalysts prepared in Examples 1, 2, and Comparative Example 1 of this invention. It can be seen that, compared to the standard PDF card (PDF#28-0317), a distinct single diffraction peak is observed at 2θ = 50.673°, proving the presence of a hexagonal crystal phase in the catalyst. Similarly, compared to the standard PDF card (PDF#30-0873), a distinct diffraction peak is observed at 2θ = 60°-65°, proving the presence of an orthorhombic crystal system in the catalyst. Therefore, it can be concluded that the catalysts prepared in Examples 1 and 2 of this invention should contain both orthorhombic and hexagonal Nb₂O₅ phases, i.e., niobium pentoxide transforms from an orthorhombic crystal form to a hexagonal crystal form.

[0101] XPS tests were performed on the catalyst prepared in Example 1, and the results are shown in [Figure 1]. Figure 4 and Figure 5 As shown, from Figure 4 As can be seen from the above, the catalyst prepared by this invention contains titanium, niobium, oxygen, and nitrogen elements, indicating the successful preparation of the catalyst. From... Figure 5 As can be seen from (b), compared with the Nb₂O₅ prepared in Comparative Example 1, the niobium binding energy position of the catalyst prepared in this invention is shifted; from Figure 5 As can be seen from (d), the satellite peaks of titanium in the TiO2 prepared in Comparative Example 2 are significantly increased, indicating a strong chemical interaction between titanium and niobium; from oxygen ( Figure 5 -c) and nitrogen ( Figure 5 The fine spectrum of -a) shows that the prepared catalyst surface has abundant hydroxyl and amino groups.

[0102] The specific surface area, pore volume, and pore size of niobium pentoxide in Examples 1-5 and Comparative Examples 1-4 were measured using a physical adsorption instrument (model ASAP2460, Micron Instruments, USA). The results are shown in Table 1. It can be seen that Ti modification of niobium pentoxide can greatly increase its pore volume, pore size, and specific surface area. Although Zr modification can also increase the pore volume, pore size, and specific surface area of ​​niobium pentoxide, the effect is not significant.

[0103] Table 1. Physicochemical properties of the catalysts prepared in each example and comparative example.

[0104]

[0105] Experimental Example 2

[0106] This experimental example examines the application of the catalysts prepared in the above examples and comparative examples in the catalytic oxidative desulfurization reaction, including the following steps:

[0107] A simulated oil was prepared using dibenzothiophene as the sulfur-containing compound and dodecane as the solvent. 20 mL of the simulated oil with a sulfur content of 200 ppm was added to a three-necked flask containing 0.05 g of catalyst. The flask was placed in a magnetically stirred water bath. A 30% hydrogen peroxide solution was added to the oil phase at an oxygen-to-sulfur molar ratio of 1:1. Samples were taken every 10 minutes, and the supernatant was centrifuged. The supernatant of the centrifuged sample was then placed in a sample tube. The sulfur content in the simulated oil after the reaction was measured using a sulfur-nitrogen analyzer to evaluate the desulfurization performance of the catalyst. The test data were recorded, and the desulfurization rate was calculated.

[0108] The formula for calculating the oxidative desulfurization efficiency is: Desulfurization rate (%) = (C0-Ct) / C0×100%, where C0 is the simulated oil sulfur content (DBT) and Ct is the real-time sulfur content of the substrate.

[0109] from Figure 6 As shown in Table 2, at 50℃, among the catalysts prepared in Examples 1-5 and Comparative Examples 1-4, the TiNbOx (5:100)-unmodified catalyst prepared in Comparative Example 3 exhibits the lowest catalytic activity without amino modification. This is because the unmodified catalyst has fewer polar substances on its surface, and the sulfones generated by catalytic oxidation cannot be removed from the oil in time, resulting in a lower desulfurization rate. Compared with Comparative Examples 1-4, the catalysts prepared in Examples 1-5 of this invention all show better desulfurization performance. Surface titanium doping enhances the catalytic oxidation desulfurization performance of niobium pentoxide. With the increase of titanium doping amount, the desulfurization performance of the catalyst shows a trend of first increasing and then decreasing, that is, more titanium doping is not necessarily better; a ratio of 5:100 is preferred. Comparative Example 4 also has a certain desulfurization effect, but the effect is not good; the desulfurization rate cannot reach 100% within 60 minutes, meaning that deep desulfurization cannot be achieved at low temperatures.

[0110] Table 2. Desulfurization effect of each embodiment and comparative example.

[0111]

[0112] from Figure 7 As can be seen from the data, the TiNbOx (5:100) prepared in Example 1 has a desulfurization rate close to 100% at 60℃ for 10 min; at 20 min, the desulfurization rate can reach 100% at both 50℃ and 60℃, which means that the catalyst prepared in this invention can achieve deep desulfurization at low temperature and in a short time.

[0113] Experimental Example 3

[0114] After the catalytic oxidation adsorption desulfurization reaction in Experiment Example 2 was completed, the catalyst was separated by centrifugation. The collected catalyst was ultrasonically dispersed in 10 mL of acetonitrile, and centrifuged after magnetic stirring for 30 min at room temperature. The collected solid catalyst was washed three times with acetonitrile again. Finally, the solid catalyst was placed in an oven and dried at 100 °C for 12 h. The dried regenerated catalyst can be used for the next cycle experiment.

[0115] The recycling performance of TiNbOx (5:100) was determined under the conditions of catalyst dosage of 0.05 g, oxygen-sulfur molar ratio of 1:1, and 50 °C. The results are as follows: Figure 8 As shown in -a, after 10 cycles, the desulfurization performance of the catalyst did not show a significant decrease, demonstrating excellent cycle performance.

[0116] After the 10th cycle, TiNbOx(5:100) was centrifuged and dried from the simulated oil. The XRD patterns of fresh and recovered TiNbOx(5:100) catalysts were studied to determine the structural stability of the catalysts. The test results are as follows: Figure 8 As shown in -b. It is worth noting that there is almost no difference between the XRD patterns of fresh and recycled TiNbOx(5:100), indicating that its structure is stable and has good reusability.

[0117] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for desulfurizing fuel oil, characterized in that, Includes the following steps: The reaction is carried out in the presence of a hollow porous bimetallic desulfurization catalyst and an oxidant; the reaction temperature is 30-60℃. The preparation method of the desulfurization catalyst includes the following steps: (1) Niobium compound, template agent, titanium compound and carbon balls are added to solvent to obtain a mixture; (2) The mixture is added to an amino precipitate solution for reaction, calcined, and carbon balls and template agent are removed to obtain a crude product; (3) React the crude product with the amino-modified solution.

2. The fuel oil desulfurization method according to claim 1, characterized in that, The oxidant is hydrogen peroxide; The sulfur content in the fuel is 100-500 ppm.

3. The fuel oil desulfurization method according to claim 1, characterized in that, The amino-modified liquid comprises at least one of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, and diethylenetriaminopropyltrimethoxysilane; and / or The mass ratio of the crude product to the volume of the amino-modified solution is 1:0.2-0.3, with a ratio of g / mL; and / or, The amino precipitate is an aqueous solution of an amino precipitant; The concentration of the amino precipitate is 2-2.5 mol / L.

4. The fuel oil desulfurization method according to claim 3, characterized in that, The amino precipitant includes at least one of urea, ammonium bicarbonate, and ammonia water.

5. The fuel oil desulfurization method according to claim 1, characterized in that, The niobium compound includes at least one of niobium pentachloride, ammonium oxalate hydrate of niobate, and niobium ethoxide, and / or, The titanium compound includes at least one of titanium tetrachloride, titanium trichloride, and tetrabutyl titanate; and / or, The template agent is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer, and / or, The solvent includes at least one selected from anhydrous ethanol, deionized water, toluene, and xylene; and / or, The ratio of the niobium compound, template agent, carbon balls, solvent and amino precipitant is 100g: 50-200g: 5-15g: 1000-3000mL: 1400-1500mL.

6. The fuel oil desulfurization method according to claim 5, characterized in that, The niobium compound is ammonium oxalate hydrate.

7. The fuel oil desulfurization method according to claim 5, characterized in that, The titanium compound is titanium tetrachloride.

8. The fuel oil desulfurization method according to claim 5, characterized in that, The template agent is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

9. The fuel oil desulfurization method according to claim 1 or 4, characterized in that, In step (1), the particle size of the carbon spheres is 5-50 nm; and / or, The mixing temperature is 40-50℃, and the time is 20-40 min; and / or, The method also includes an alkali activation treatment step for the carbon balls, specifically: dispersing the carbon balls in the amino precipitate solution, reacting at 45-55℃ for 10-14 hours, and obtaining the product after filtration and drying; the mass ratio of the carbon balls to the volume of the amino precipitate solution is 5:15-30, and the ratio is g / mL.

10. The fuel oil desulfurization method according to claim 1, characterized in that, In step (2), the reaction temperature is 90-110℃, and the reaction time is 8-12h; and / or, The reaction also includes a stirring step prior to the reaction, wherein the stirring temperature is 40-50°C and the stirring time is 10-14 hours; and / or, The mixture is added by means of ultrasonic atomization spraying; and / or, In the calcination step, the mixture is heated to 700-800℃ at a heating rate of 3-7℃ / min and calcined for 4-5 hours.

11. The fuel oil desulfurization method according to claim 1, characterized in that, Step (3) also includes an organic solvent, wherein the organic solvent is at least one of toluene, xylene, and ethanol; The mass ratio of the crude product to the volume ratio of the organic solvent is 1:90-110, with a ratio of g / mL; and / or, The reaction temperature is 100-110℃, and the time is 22-26 hours; and / or, The reaction is carried out under a nitrogen atmosphere at a flow rate of 50-300 mL / min; and / or, After the reaction is completed, a drying step is also included, wherein the drying temperature is 100-110℃ and the time is 8-12h.

12. The fuel oil desulfurization method according to claim 11, characterized in that, The nitrogen flow rate is 200 mL / min.

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