A porous ionic liquid containing supported high-entropy metal oxides, its preparation method and application

Abstract

This invention discloses a porous ionic liquid containing supported high-entropy metal oxides, its preparation method, and its application. Five non-noble metal salts from the secondary group are dissolved in water to obtain a mixed aqueous solution of the metal salts. SBA-15 molecular sieve is added to the mixed aqueous solution and stirred thoroughly to obtain a suspension. The suspension is heated to dryness, ground, washed with deionized water, centrifuged, and dried to obtain a loose solid powder. The solid powder is calcined at high temperature under a protective atmosphere to obtain the supported high-entropy metal oxides. Finally, the obtained supported high-entropy metal oxides are uniformly dispersed in the ionic liquid to obtain the final product. This porous ionic liquid serves as both an extractant and a catalyst. It not only overcomes the barrier of constructing porous ionic liquids solely using intermolecular steric hindrance but also demonstrates excellent removal ability of aromatic sulfides and good catalyst cycling performance in the ECODS system.

Description

Technical Field

[0001] This invention relates to the field of catalytic material preparation, specifically to a porous ionic liquid containing supported high-entropy metal oxides, its preparation method, and its application. Background Technology

[0002] Fuel oil contains many aromatic sulfides, such as thiophene, benzothiophene, dibenzothiophene, and their derivatives, which have stable conjugated structures and are difficult to remove using traditional hydrodesulfurization (HDS) processes. Currently, existing novel desulfurization methods include adsorption desulfurization (ADS), extraction desulfurization (EDS), oxidative desulfurization (ODS), and biological desulfurization (BDS). Among these, ODS has gained favor among scientists due to its more effective removal of aromatic sulfides. However, oxidative desulfurization reactions involve oil oxidation side reactions, and separating the oil from the catalyst is difficult. Therefore, combining extraction coupled with catalytic oxidation (ECODS) to create a two-phase system of extraction and oxidative desulfurization, using a liquid extractant to extract oil-phase sulfides and then accelerating the oxidative desulfurization rate in an oxygen-containing environment, is considered a promising method. The key lies in designing a catalyst that possesses both extraction and oxidative desulfurization capabilities.

[0003] Ionic liquids (ILs) are organic molten salts composed of organic cations and organic (inorganic) anions, exhibiting high ionic conductivity, solubility, and stability, and existing in liquid form at room temperature. Notably, ionic liquids are also key materials for preparing porous liquids using readily available porous solid materials. Porous ionic liquids (PILs) offer significant advantages in gas trapping. Because IL molecules are too large to enter the pores of porous materials, the micropores of solute molecules become dry, allowing gas molecules to enter. They rely on steric mechanics to create permanent micropores and gas trapping capabilities. Furthermore, utilizing the different hydrophilic and hydrophobic properties of solvent molecules and porous solute molecules to construct PILs has proven to be a feasible and innovative method in this invention.

[0004] High entropy alloy oxides (HEOs) are composed of five or more metal cations and possess high-temperature stability. The ability of various HEO structures to generate and control oxygen vacancies can enhance the catalytic activity of various oxidation reactions. However, due to the diverse structures and difficult-to-tune morphology of HEOs, the active sites are unevenly exposed, preventing HEOs from fully realizing their catalytic advantages in oxidation reactions. Summary of the Invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to address the shortcomings of existing high-entropy alloy oxide catalysts, such as uneven exposure of active sites and difficulty in molecular mass transfer, and to provide a novel method for constructing porous ionic liquids. By using supported high-entropy metal oxides and room temperature ionic liquids, a thermodynamically based porous ionic liquid is designed to significantly improve catalytic activity.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a porous ionic liquid containing a supported high-entropy metal oxide includes the following steps:

[0008] (1) Dissolve five non-precious metal salts in water to obtain a mixed aqueous solution of metal salts;

[0009] (2) Add molecular sieve SBA-15 to the mixed aqueous solution of step (1) and stir thoroughly to obtain a suspension;

[0010] (3) The suspension in step (2) is heated at a constant temperature to evaporate to dryness, ground and washed with deionized water, centrifuged and dried to obtain loose solid powder;

[0011] (4) The solid powder obtained in step (3) is subjected to high-temperature calcination in a protective atmosphere to obtain a supported high-entropy metal oxide.

[0012] (5) The supported high-entropy metal oxide obtained in step (4) is uniformly dispersed into the ionic liquid to obtain the final product.

[0013] Specifically, in step (1), the five non-precious metal salts are cobalt salt, iron salt, molybdenum salt, nickel salt, and copper salt, and the total mass percentage of the five non-precious metal salts in the mixed aqueous solution is 1 to 15 wt%.

[0014] Specifically, in step (2), the molecular sieve SBA-15 is a commercial-grade ordered hexagonal mesoporous silica molecular sieve with a pore size between 7 and 11 nm; the molecular sieve SBA-15 is mixed with the mixed aqueous solution in step (1) at a mass-volume ratio of 0.1 to 0.5 g / ml.

[0015] Preferably, in step (2), the stirring speed is set to 500-800 rpm, and the mixture is stirred at 30-60°C for 6-12 hours to obtain a suspension.

[0016] Preferably, in step (3), the constant temperature heating and drying temperature is 80-100℃, the time is 24-48 hours, and the stirring is carried out continuously during the drying process, with the stirring speed set to 500-800 revolutions per minute.

[0017] Preferably, in step (3), each 0.01 to 0.05 g of solid powder is washed with 30 mL of deionized water, and after washing, it is centrifuged at a speed of 8000 to 10000 rpm for 1 to 5 minutes.

[0018] Specifically, in step (4), the calcination treatment refers to heating to 500-800°C at a rate of 2-10°C / min and calcining for 2-4 hours in air or a protective atmosphere containing 1-30% oxygen.

[0019] Preferably, in step (5), the ionic liquid is an ionic liquid with hydrophobic side chains, selected from any one of 1-butyl-3-trimethylimidazolium tetrafluoroborate, 1-octyl-3-trimethylimidazolium tetrafluoroborate, 1-butyl-3-trimethylimidazolium hexafluoroborate, and 1-octyl-3-trimethylimidazolium hexafluoroborate; the supported high-entropy metal oxide and the ionic liquid with hydrophobic side chains are mixed at a mass ratio of 1:2 to 5, and the dispersion is carried out by magnetic stirring at a speed of 400 to 800 rpm.

[0020] Furthermore, the porous ionic liquid containing supported high-entropy metal oxides prepared by the above preparation method is also within the scope of protection of this invention.

[0021] Furthermore, the present invention also claims the use of the above-mentioned porous ionic liquid containing supported high-entropy metal oxides in the extraction coupled with catalytic oxidation to remove organic sulfur compounds from fuel oil.

[0022] Beneficial effects:

[0023] (1) The supported high entropy metal oxide prepared in this invention enhances the molecular mass transfer rate by utilizing the high activation ability of HEOs active sites to oxygen on the one hand, and overcomes the defect of insufficient exposure of HEOs active sites by utilizing the high specific surface area of ​​SBA-15 to highly disperse HEOs on the other hand.

[0024] (2) Based on the difference in hydrophilicity of functional groups between ionic liquids and supported high-entropy metal oxides, this invention yields a novel porous ionic liquid with high active sites, high porosity, and efficient oxygen storage capacity. The obtained porous ionic liquid serves as both an extractant and a catalyst. It not only overcomes the barrier of constructing porous ionic liquids solely using intermolecular steric hindrance, but also demonstrates excellent removal capabilities for aromatic sulfides and good catalyst cycling performance in the ECODS system. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0026] Figure 1 This is a schematic diagram illustrating the synthesis of the supported high-entropy metal oxide of the present invention.

[0027] Figure 2 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the materials in Example 1. Specifically, a is the SEM image of SBA-15, b is the SEM image of the supported high-entropy metal oxide, c and d are the TEM images of the supported high-entropy metal oxide, and e and f are the elemental distribution maps of the supported high-entropy metal oxide.

[0028] Figure 3 These are the nitrogen adsorption-desorption curves and pore size distribution diagrams of the material in Example 1.

[0029] Figure 4 These are the Fourier transform infrared (FT-IR) spectrum and thermogravimetric (TG) curve of the porous ionic liquid prepared in Example 1. Detailed Implementation

[0030] The present invention can be better understood from the following embodiments.

[0031] Example 1

[0032] (1) Weigh out cobalt nitrate, ferric nitrate, ammonium molybdate, nickel nitrate and copper nitrate. The amount of each metal salt is 0.01 mol. Mix all the metal salts and dissolve them in deionized water to obtain a mixed aqueous solution of metal salts, such that the mass percentage of metal salts in the mixed aqueous solution is 5 wt%.

[0033] (2) Add 1g of molecular sieve SBA-15 to 10mL of mixed aqueous solution of metal salts, stir at 30℃ for 6 hours, and set the rotation speed to 600 rpm to obtain a pale yellow suspension.

[0034] (3) The suspension was heated at 80°C and evaporated to dryness. The rotation speed was set to 600 rpm. The evaporated solid was then ground to obtain a light yellow solid powder.

[0035] (4) Wash the solid powder with deionized water and centrifuge. Repeat this step three times to obtain a white suspension and dry it to obtain a white loose solid powder.

[0036] (5) The supported high-entropy metal oxide is obtained by calcining in air for 2 hours at a temperature of 550°C and a heating rate of 5°C / min.

[0037] (6) Take 0.05g of the above-mentioned supported high-entropy metal oxide and add it to 4mL of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Use a magnetic stirrer to evenly disperse it into the ionic liquid to obtain a porous ionic liquid.

[0038] Figure 1 This is a schematic diagram illustrating the synthesis of the supported high-entropy metal oxide of the present invention.

[0039] Figure 2 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the material in Example 1. Among them:

[0040] Figure 2 a is a SEM image of the untreated molecular sieve SBA-15 in Example 1. As can be seen from the image, the macroscopic morphology of SBA-15 is a rod-shaped structure with a radial dimension of 50 to 200 μm.

[0041] Figure 2 b is an SEM image of the molecular sieve after the addition of high-entropy oxide in Example 1. It can be seen that the loading did not affect the morphology of the carrier molecular sieve.

[0042] Figure 2 cd are the lattice fringes of the loaded high-entropy metal oxide under HRTEM. As can be seen from the figure, the loading did not affect the pore structure of SBA-15.

[0043] Figure 2 ef is the elemental distribution diagram of the supported high-entropy metal oxide in Example 1. It can be seen that the five metal elements are evenly distributed on SBA-15, indicating the formation of high-entropy metal oxide.

[0044] Figure 3 These are the nitrogen adsorption-desorption curves and pore size distribution diagrams of the material in Example 1. Wherein:

[0045] Figure 3 Figure a shows the nitrogen adsorption-desorption curves and pore size distribution curves of SBA-15 before and after loading in Example 1. It can be seen that the hysteresis loops of SBA-15 exhibit a significant H1 hysteresis loop within the relative pressure range of 0.6-0.9, indicating that SBA-15 has an ordered mesoporous structure. The isotherms of supported high-entropy metal oxides show typical mesoporous structures, which is consistent with the information obtained from the isotherms of SBA-15.

[0046] Figure 3 b is the pore size distribution curve of Example 1. This curve shows that there are abundant mesopores in SBA-15 before and after loading, and the pore size is mostly in the range of 6-8 nm, which is consistent with the pore size range of the selected SBA-15.

[0047] Figure 4 These are the Fourier transform infrared (FT-IR) spectrum and thermogravimetric (TG) curve of the porous ionic liquid prepared in Example 1. Wherein:

[0048] Figure 4a is the Fourier transform infrared (FT-IR) spectrum of the porous ionic liquid in Example 1. The figure shows that the addition of the supported high-entropy metal oxide did not change the structure of the ionic liquid, proving that the supported high-entropy metal oxide exists stably and uniformly in the ionic liquid after physical dispersion, and does not chemically react with the ionic liquid.

[0049] Figure 4 b is the thermogravimetric (TG) curve of the porous ionic liquid in Example 1. The results show that below 330°C, neither the ionic liquid nor the supported high-entropy metal oxide experienced significant mass loss, demonstrating their good thermal stability within this temperature range. Furthermore, the addition of the supported high-entropy metal oxide had a negligible impact on the thermal stability of the ionic liquid, further confirming the excellent structural stability of the constructed porous ionic liquid environment.

[0050] Example 2

[0051] (1) Weigh out cobalt nitrate, ferric nitrate, ammonium molybdate, nickel nitrate and copper nitrate. The amount of each metal salt is 0.01 mol. Mix all the metal salts and dissolve them in deionized water to obtain a mixed aqueous solution of metal salts, such that the mass percentage of metal salts in the mixed aqueous solution is 5 wt%.

[0052] (2) Add 1g of molecular sieve SBA-15 to 10mL of mixed aqueous solution of metal salts, stir at 30℃ for 6 hours, and set the rotation speed to 600 rpm to obtain a pale yellow suspension.

[0053] (3) The suspension was heated at 80°C and evaporated to dryness. The rotation speed was set to 600 rpm. The evaporated solid was then ground to obtain a light yellow solid powder.

[0054] (4) Wash the solid powder with deionized water and centrifuge. Repeat this step three times to obtain a white suspension and dry it to obtain a white loose solid powder.

[0055] (5) Calcination at high temperature in air for 2 hours, at a temperature of 650°C and a heating rate of 5°C / min, yields a supported high-entropy metal oxide.

[0056] (6) Take 0.05g of the above-mentioned supported high-entropy metal oxide and add it to 4mL of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Use a magnetic stirrer to evenly disperse it into the ionic liquid to obtain a porous ionic liquid.

[0057] Example 3

[0058] (1) Weigh out cobalt nitrate, ferric nitrate, ammonium molybdate, nickel nitrate and copper nitrate. The amount of each metal salt is 0.01 mol. Mix all the metal salts and dissolve them in deionized water to obtain a mixed aqueous solution of metal salts, such that the mass percentage of metal salts in the mixed aqueous solution is 3 wt%.

[0059] (2) Add 1g of molecular sieve SBA-15 to 10mL of mixed aqueous solution of metal salts, stir at 30℃ for 6 hours, and set the rotation speed to 600 rpm to obtain a pale yellow suspension.

[0060] (3) The suspension was heated at 80°C and evaporated to dryness. The rotation speed was set to 600 rpm. The evaporated solid was then ground to obtain a light yellow solid powder.

[0061] (4) Wash the solid powder with deionized water and centrifuge. Repeat this step three times to obtain a white suspension and dry it to obtain a white loose solid powder.

[0062] (5) The supported high-entropy metal oxide is obtained by calcining in air for 2 hours at a temperature of 550°C and a heating rate of 5°C / min.

[0063] (6) Take 0.05g of the above-mentioned supported high-entropy metal oxide and add it to 4mL of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Use a magnetic stirrer to evenly disperse it into the ionic liquid to obtain a porous ionic liquid.

[0064] Example 4

[0065] (1) Weigh out cobalt nitrate, ferric nitrate, ammonium molybdate, nickel nitrate and copper nitrate. The amount of each metal salt is 0.01 mol. Mix all the metal salts and dissolve them in deionized water to obtain a mixed aqueous solution of metal salts, such that the mass percentage of metal salts in the mixed aqueous solution is 10 wt%.

[0066] (2) Add 1g of molecular sieve SBA-15 to 10mL of mixed aqueous solution of metal salts, stir at 30℃ for 6 hours, and set the rotation speed to 600 rpm to obtain a pale yellow suspension.

[0067] (3) The suspension was heated at 80°C and evaporated to dryness. The rotation speed was set to 600 rpm. The evaporated solid was then ground to obtain a light yellow solid powder.

[0068] (4) Wash the solid powder with deionized water and centrifuge. Repeat this step three times to obtain a white suspension and dry it to obtain a white loose solid powder.

[0069] (5) The supported high-entropy metal oxide is obtained by calcining in air for 2 hours at a temperature of 550°C and a heating rate of 5°C / min.

[0070] (6) Take 0.05g of the above-mentioned supported high-entropy metal oxide and add it to 4mL of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. Use a magnetic stirrer to evenly disperse it into the ionic liquid to obtain a porous ionic liquid.

[0071] Example 5

[0072] (1) Weigh out cobalt nitrate, ferric nitrate, ammonium molybdate, nickel nitrate and ferric nitrate, with each metal salt being 0.01 mol. Mix all the metal salts and dissolve them in deionized water to obtain a mixed aqueous solution of metal salts, such that the mass percentage of metal salts in the mixed aqueous solution is 5 wt%.

[0073] (2) Add 1g of molecular sieve SBA-15 to 10mL of mixed aqueous solution of metal salts, stir at 30℃ for 6 hours, and set the rotation speed to 600 rpm to obtain a pale yellow suspension.

[0074] (3) The suspension was heated at 80°C and evaporated to dryness. The rotation speed was set to 600 rpm. The evaporated solid was then ground to obtain a light yellow solid powder.

[0075] (4) Wash the solid powder with deionized water and centrifuge. Repeat this step three times to obtain a white suspension and dry it to obtain a white loose solid powder.

[0076] (5) The supported high-entropy metal oxide is obtained by calcining in air for 2 hours at a temperature of 550°C and a heating rate of 5°C / min.

[0077] (6) Take 0.05g of the above-mentioned supported high-entropy metal oxide and add it to 4mL of ionic liquid 1-octyl-3-methylimidazolium tetrafluoroborate. Use a magnetic stirrer to evenly disperse it into the ionic liquid to obtain a porous ionic liquid.

[0078] Examples 6-12

[0079] The porous ionic liquids obtained in Examples 1-5 were used in an extraction-coupled catalytic oxidation process to remove sulfides from oil products. The following describes the simulated diesel oil types and the setup of the oxidative desulfurization experimental apparatus:

[0080] The model oil is made by dissolving dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and 4-methyldibenzothiophene (4-MDBT) in n-dodecane, and adding n-hexadecane as an internal standard.

[0081] A 20 mL sample of simulated oil was transferred to a three-necked flask, and 4 mL of the porous ionic liquid synthesized in the previous example was added. The flask was placed in a 120°C constant-temperature oil bath and connected to a reflux condenser. Oxygen was continuously introduced into the system at a flow rate of 150 mL / min, while a magnetic stirrer was activated. During the reaction, the sulfur content in the oil was quantitatively detected using a gas chromatograph, and the desulfurization rate was calculated using the following formula.

[0082]

[0083] The experimental results are shown in Table 1.

[0084] Table 1

[0085]

[0086] As shown in Table 1, the porous ionic liquids synthesized in all examples exhibit good removal efficiency for sulfides in model oils. Among them, the porous ionic liquid synthesized in Example 1 shows the highest removal efficiency for dibenzothiophene (DBT) under the same conditions, with the removal efficiency being DBT>4-MDBT>4,6-DMDBT.

[0087] This invention provides a porous ionic liquid containing supported high-entropy metal oxides, its preparation method, and its application. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing a porous ionic liquid containing supported high-entropy metal oxide, characterized in that, The preparation method comprises the following steps: (1) dissolving five kinds of non-noble metal salt of sub-group in water to obtain a mixed aqueous solution of metal salt; (2) adding molecular sieve SBA-15 into the mixed aqueous solution of step (1) and stirring sufficiently to obtain a suspension; (3) heating and evaporating the suspension in step (2) at constant temperature, grinding and washing with deionized water, centrifuging and drying to obtain loose solid powder; (4) performing high-temperature calcination treatment on the solid powder obtained in step (3) in a protective atmosphere to obtain a supported high-entropy metal oxide; (5) uniformly dispersing the supported high-entropy metal oxide obtained in step (4) into ionic liquid to obtain the supported high-entropy metal oxide-containing porous ionic liquid. In step (1), the five kinds of non-noble metal salt of sub-group are respectively cobalt salt, iron salt, molybdenum salt, nickel salt and copper salt, and the total mass percentage of the five kinds of non-noble metal salt of sub-group in the mixed aqueous solution is 1-15 wt%. In step (5), the ionic liquid is a hydrophobic side chain-containing ionic liquid selected from any one of 1-butyl-3-trimethyl imidazole tetrafluoroborate, 1-octyl-3-trimethyl imidazole tetrafluoroborate, 1-butyl-3-trimethyl imidazole hexafluoroborate and 1-octyl-3-trimethyl imidazole hexafluoroborate; and the supported high-entropy metal oxide and the hydrophobic side chain-containing ionic liquid are mixed at a mass ratio of 1:2-5.

2. The method for preparing a supported high-entropy metal oxide-containing porous ionic liquid according to claim 1, characterized in that, In step (2), the molecular sieve SBA-15 is a commercial ordered hexagonal mesoporous silica molecular sieve with a pore size of 7-11 nm; and the molecular sieve SBA-15 is mixed with the mixed aqueous solution of step (1) at a mass / volume ratio of 0.1-0.5 g / mL.

3. The method for preparing a supported high-entropy metal oxide containing porous ionic liquid according to claim 1, characterized in that, In step (2), the stirring speed is set to 500-800 rpm, and the stirring is performed at 30-60℃ for 6-12 hours to obtain the suspension.

4. The method of claim 1, wherein the method is characterized by, In step (3), the temperature for heating and evaporating at constant temperature is 80-100℃, and the time is 24-48 hours; and the stirring is continuously performed during the evaporating process, and the stirring speed is set to 500-800 rpm.

5. The method of claim 1, wherein the method is characterized by, In step (3), 30 mL of deionized water is used to wash every 0.01-0.05 g of solid powder; and after the washing is completed, the solid powder is centrifuged at a centrifugal speed of 8000-10000 rpm for 1-5 minutes.

6. The method of claim 1, wherein the method is characterized by, In step (4), the calcination treatment refers to heating at a rate of 2-10℃ / min to 500-800℃ in air or a protective atmosphere containing oxygen at a proportion of 1-30% for 2-4 hours.

7. The method of claim 1, wherein the method is characterized by, In step (5), the dispersion is performed by magnetic stirring, and the stirring speed is set to 400-800 rpm.

8. The supported high-entropy metal oxide-containing porous ionic liquid prepared by the preparation method of any one of claims 1-7.

9. The application of the supported high-entropy metal oxide-containing porous ionic liquid of claim 8 in removing organic sulfides in fuel oil.

Images