Catalyst as well as preparation method and application thereof

Abstract

The invention relates to a catalyst and a preparation method and application thereof, and belongs to the technical field of catalysis. The method comprises the following steps: obtaining a template, wherein the template has a pore structure; filling metal salt into the pore structure of the template to obtain a first intermediate; sintering the intermediate to convert the metal salt into a metal oxide to obtain a second intermediate; and removing the template of the second intermediate to obtain the catalyst, according to the present invention, the metal oxide catalyst is prepared through the template method, the metal oxide catalyst can have the template gap structure, the specific surface area of the metal oxide with the structure is large, the contact sites with the electrolyte are rich, and the ordered structure provides the smooth path for the electron transfer; therefore, the catalyst has better catalytic performance. The whole preparation process can be carried out under normal pressure, and the prepared raw materials have the characteristics of low price and environmental protection, so that the preparation method has a great industrial production prospect.

Description

Technical Field

[0001] This application relates to the field of catalytic technology, and particularly to a catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] The molecular structure of 2,5-furandicarboxylic acid (FDCA) is similar to that of terephthalic acid, and it has good stability. It is one of the potential substitutes for terephthalic acid and is widely used in fields such as polyesters, polyamides, and plasticizers. The performance of the polyester material synthesized with 2,5-furandicarboxylic acid (FDCA) as a monomer is similar to that of traditional PTA. 2,5-Furandicarboxylic acid (FDCA) is obtained from biomass and is a high-value-added product with carbon neutrality. The clean and carbon-neutral 2,5-furandicarboxylic acid (FDCA) has great application prospects.

[0003] There are various production routes for biomass-based 2,5-furandicarboxylic acid (FDCA). A variety of bio-based chemicals such as 5-hydroxymethylfurfural (HMF), furoic acid, 2-ethylfuran, and hexanedioic acid can be used as precursors. Among them, the technical route of preparing 2,5-furandicarboxylic acid (FDCA) by the oxidation of 5-hydroxymethylfurfural has been studied most widely, and the related processes are more mature.

[0004] 5-Hydroxymethylfurfural (HMF) is a bio-based chemical with relatively active chemical properties. It can be obtained by the dehydration of glucose or fructose and is a recognized platform compound with broad application prospects. Currently, a variety of processes for preparing 2,5-furandicarboxylic acid (FDCA) by the oxidation of 5-hydroxymethylfurfural (HMF) have been developed. Such as the direct oxidation method using strong oxidants such as potassium permanganate and hydrogen peroxide, the noble metal catalytic oxidation method using oxygen as an oxidant, the pressurized catalytic oxidation method using air as an oxidant, the biological method using enzymes as catalysts, and the electrocatalytic method. However, the traditional chemical oxidation method has harsh conditions, low conversion rate, consumes a large amount of energy and chemical reagents, causes great damage to the environment, and has a huge carbon emission during the production process. Although emerging biological methods such as enzyme catalysis can achieve the catalytic oxidation of 5-hydroxymethylfurfural (HMF) under mild conditions, due to the poor stability of enzymes and their relatively high prices, etc., the catalytic method for preparing 2,5-furandicarboxylic acid (FDCA) is restricted in practical industrial applications.

[0005] The electrocatalytic method is a production process that has emerged in recent years for preparing 2,5-furandicarboxylic acid (FDCA) at room temperature and atmospheric pressure. It uses electricity as an external driving force and realizes the catalytic oxidation of 5-hydroxymethylfurfural (HMF) under the mediation of an electrocatalyst. The electrocatalytic method has mild reaction conditions, is easy to control, can use clean electric energy and by-produces green hydrogen, and has broad application prospects, so it has received extensive attention from researchers.

[0006] For the electrochemical method, to achieve the industrial popularization and application of the electrochemical method, the key lies in developing an electrochemical catalyst that is easy to fabricate, low-cost, and highly efficient and stable. Chinese Patent Application CN116590724A discloses a manganese-doped nickel sulfide electrocatalyst for the oxidation of 5-hydroxymethylfurfural (HMF). This catalyst can achieve a large electrolysis current density at the industrial level, but the preparation of the catalyst uses the hydrothermal method, making it difficult to scale up industrially. Summary of the Invention

[0007] This application provides a catalyst, its preparation method, and application to improve the problem of the difficult preparation of the catalyst for the electrocatalytic preparation of 2,5-furandicarboxylic acid.

[0008] In the first aspect, this application provides a preparation method of a catalyst, and the method includes:

[0009] Obtain a template, and the template has a pore structure;

[0010] Fill a metal salt into the pore structure of the template to obtain a first intermediate;

[0011] Sinter the intermediate to convert the metal salt into a metal oxide to obtain a second intermediate;

[0012] Remove the template of the second intermediate to obtain the catalyst.

[0013] The above technical solution provided by the embodiments of this application has the following advantages compared with the prior art:

[0014] The method provided by the embodiments of this application prepares a metal oxide catalyst through the template method. This metal oxide catalyst can have the void structure of the template. The metal oxide with this structure has a larger specific surface area, more abundant contact sites with the electrolyte, and its ordered structure also provides a smoother path for electron transfer. Therefore, it has better catalytic performance. The entire preparation process can be carried out under normal pressure, and the raw materials for preparation are all low-cost and environmentally friendly, showing great prospects for industrial production.

[0015] As an optional implementation manner, the template includes molecular sieve.

[0016] In the above implementation process, by utilizing the characteristics of the molecular sieve having many uniformly sized pores and neatly arranged cavities in its structure, using its cavities as the preset shape of the catalyst, the catalyst has a larger specific surface area, more abundant contact sites with the electrolyte, and its ordered structure also provides a smoother path for electron transfer. Therefore, it has better catalytic performance.

[0017] As an optional implementation manner, the pore structure of the template is a mesoporous structure.

[0018] In the above implementation process, the mesoporous structure can endow the catalyst with a large specific surface area, which is beneficial to its catalytic performance.

[0019] As an alternative implementation, the pore size of the pore structure of the template is 3 to 15 nanometers.

[0020] In the above implementation process, a pore size of 3 to 15 nanometers is more beneficial to the specific surface area of the catalyst, and thus beneficial to its catalytic performance.

[0021] As an alternative implementation, the material of the template includes silica.

[0022] In the above implementation process, silica can be removed by a relatively simple method, reducing the preparation difficulty and being beneficial to the preparation of the catalyst.

[0023] As an alternative implementation, the template includes at least one of SBA-15 and KIT-6.

[0024] As an alternative implementation, the metal salt includes metal acetate.

[0025] As an alternative implementation, the metal acetate includes at least one of the acetates of Ni, Co, Fe, Cu, Mn, and Ag.

[0026] As an alternative implementation, the metal acetate includes at least two of the acetates of Ni, Co, Fe, Cu, Mn, and Ag.

[0027] As an alternative implementation, the sintering temperature is 500 to 700 °C; and / or

[0028] The sintering time is 1 to 3 hours.

[0029] As an alternative implementation, the sintering temperature is 550 to 650 °C; and / or

[0030] The sintering time is 1.5 to 2.5 hours.

[0031] As an alternative implementation, the sintering temperature is 590 to 610 °C; and / or

[0032] The sintering time is 1.9 to 2.1 hours.

[0033] As an alternative implementation, the removal method of the template for removing the second intermediate includes etching removal.

[0034] As an alternative embodiment, the material of the template includes silicon dioxide, and the etching solution for etching and removing includes an alkaline solution.

[0035] As an alternative embodiment, the alkaline solution includes KOH, and the molar concentration of the KOH is 0.5 - 1.5 M.

[0036] In a second aspect, the present application provides a catalyst, which is prepared by using the catalyst preparation method described in the first aspect.

[0037] In a third aspect, the present application provides an application of a catalyst. The catalyst is the catalyst described in the second aspect, and the application includes using the catalyst for electrocatalytic preparation of 2,5 - furandicarboxylic acid from 5 - hydroxymethylfurfural.

[0038] As an alternative embodiment, the electrolyte for electrocatalysis includes KOH, and the molar concentration of the electrolyte is 0.5 - 1.5 mol / L.

[0039] As an alternative embodiment, the molar concentration of the 5 - hydroxymethylfurfural is 0.1 - 1 mol / L.

[0040] As an alternative embodiment, the voltage for electrocatalysis is 2 - 5 V. Description of the Drawings

[0041] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0042] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0043] Figure 1 It is a flowchart of the method provided by the embodiment of the present application;

[0044] Figure 2 It is a schematic diagram of the reaction process of 5 - hydroxymethylfurfural provided by the embodiment of the present application;

[0045] Figure 3 It is an electron micrograph of the macroporous - structured ordered composite metal oxide for FDCA production provided by the embodiment of the present application. Detailed Embodiments

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some, but not all, of the embodiments of this application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0047] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, equipment, etc. used in this application can be obtained through market purchases or can be prepared by existing methods.

[0048] The molecular structure of 2,5-furandicarboxylic acid (FDCA) is similar to that of terephthalic acid and has good stability. It is one of the potential substitutes for terephthalic acid and is widely used in fields such as polyesters, polyamides, and plasticizers. 2,5-Furandicarboxylic acid (FDCA) is obtained from biomass and is a high-value-added product with carbon neutrality. Clean and carbon-neutral 2,5-furandicarboxylic acid (FDCA) has great application prospects.

[0049] There are various production routes for biomass-based 2,5-furandicarboxylic acid (FDCA). Many bio-based chemicals such as 5-hydroxymethylfurfural (HMF), furfural acid, 2-ethylfuran, and hexose diacid can be used as precursors. Among them, the technical route of preparing 2,5-furandicarboxylic acid (FDCA) by the oxidation of 5-hydroxymethylfurfural has been studied the most extensively, and the related processes are more mature.

[0050] 5-Hydroxymethylfurfural (HMF) is a bio-based chemical with relatively active chemical properties. It can be obtained by the dehydration of glucose or fructose and is a recognized platform compound with broad application prospects. Currently, a variety of processes for preparing 2,5-furandicarboxylic acid (FDCA) by the oxidation of 5-hydroxymethylfurfural (HMF) have been developed. Such as direct oxidation methods using strong oxidants such as potassium permanganate and hydrogen peroxide, noble metal-catalyzed oxidation methods using oxygen as the oxidant, pressurized catalytic oxidation methods using air as the oxidant, biological methods using enzymes as catalysts, and electrochemical catalytic methods.

[0051] Among them, the electrocatalytic method is a production process that has emerged in recent years for preparing 2,5-furandicarboxylic acid (FDCA) at room temperature and atmospheric pressure. It uses electricity as an external driving force and realizes the catalytic oxidation of 5-hydroxymethylfurfural (HMF) under the mediation of an electrocatalyst. The electrocatalytic method has mild reaction conditions, is easy to control, can use clean electric energy and by-product green hydrogen, and has broad application prospects, so it has received extensive attention from researchers.

[0052] For the electrochemical method, to achieve the industrial popularization and application of the electrochemical method, the key lies in developing an electrochemical catalyst that is easy to fabricate, low-cost, and highly efficient and stable. Chinese Patent Application CN116590724A discloses a manganese-doped nickel sulfide electrocatalyst for the oxidation of 5-hydroxymethylfurfural (HMF). This catalyst can achieve an industrial-level large electrolysis current density, but the preparation of the catalyst uses the hydrothermal method, which is difficult to scale up industrially.

[0053] Therefore, the inventors intend to provide a new method for preparing a catalyst to reduce the preparation difficulty of the catalyst, realize the industrial production of the catalyst, and thus promote the industrial production of 2,5-furandicarboxylic acid (FDCA).

[0054] Figure 1 The flowchart of the method provided in the embodiments of the present application is as Figure 1 shown. The embodiments of the present application provide a method for preparing a catalyst, and the method includes:

[0055] S1. Obtain a template, and the template has a pore structure;

[0056] In some embodiments, the template includes a molecular sieve. A molecular sieve refers to a material with many uniformly sized pore channels and neatly arranged cavities in its structure. Utilizing the characteristics of a molecular sieve having many uniformly sized pore channels and neatly arranged cavities in its structure, using its cavities as the preset shape of the catalyst enables the catalyst to have a large specific surface area, a richer contact site with the electrolyte, and its ordered structure also provides a smoother path for electron transfer. Therefore, it has better catalytic performance.

[0057] Further, the pore structure of the template is a mesoporous structure. A mesoporous structure refers to a pore structure with a pore diameter in the range of 2 - 50 nanometers. The pore diameter of the pore structure of the template can be 2 nanometers, 3 nanometers, 4 nanometers, 5 nanometers, 6 nanometers, 7 nanometers, 8 nanometers, 9 nanometers, 10 nanometers, 11 nanometers, 12 nanometers, 13 nanometers, 14 nanometers, 15 nanometers, 16 nanometers, 17 nanometers, 18 nanometers, 19 nanometers, 20 nanometers, 21 nanometers, 22 nanometers, 23 nanometers, 24 nanometers, 25 nanometers, 26 nanometers, 27 nanometers, 28 nanometers, 29 nanometers, 30 nanometers, 31 nanometers, 32 nanometers, 33 nanometers, 34 nanometers, 35 nanometers, 36 nanometers, 37 nanometers, 38 nanometers, 39 nanometers, 40 nanometers, 41 nanometers, 42 nanometers, 43 nanometers, 44 nanometers, 45 nanometers, 46 nanometers, 47 nanometers, 48 nanometers, 49 nanometers, or 50 nanometers, etc., and it can also be any value within the range of 2 - 50 nanometers. The mesoporous structure can enable the catalyst to have a large specific surface area, which is beneficial to its catalytic performance. Furthermore, the pore diameter of the pore structure of the template is 3 - 15 nanometers. A pore diameter of 3 - 15 nanometers is more beneficial to the specific surface area of the catalyst and thus beneficial to its catalytic performance.

[0058] In some embodiments, the material of the template includes silica. Silica can be removed in a relatively simple manner, reducing the preparation difficulty and facilitating the preparation of the catalyst.

[0059] Specifically, the template can be selected from at least one of SBA-15 and KIT-6.

[0060] Mesoporous silica SBA-15 has a two-dimensional hexagonal through-hole structure with a P6mm space group. In the XRD diffraction pattern, the main peak is near about 1°, which is the (10) crystal plane peak. The second-strongest peaks are the (11) peak and the (20) peak in sequence. Other peaks are weak and not easily observable. In addition, the silica on the SBA-15 framework is generally amorphous, and no obvious diffraction peaks are observed in wide-angle XRD diffraction. Its synthesis conforms to the neutral template mechanism (S0I): using a neutral surfactant P123 (S0), and a neutral inorganic silicon species (I0) bonded by hydrogen bonds, without strong electrostatic interactions, and with the further hydrolysis and condensation of silanol leading to the stacking of short-range hexagonal colloids and the formation of the framework. Its typical synthesis process is: under the condition of 35 - 40 °C, dissolve the triblock surfactant P123 (Aldrich, EO20PO70EO20, Ma = 5800) in an appropriate amount of deionized water, add tetraethyl orthosilicate (TEOS) and hydrochloric acid (HCl) to it, continuously stir vigorously for more than 24 h, load it into a polytetrafluoroethylene bottle for crystallization for more than 24 h, filter, wash and dry, and finally calcine at 550 °C for more than 5 h to remove the template agent or wash away the template agent by solvent reflux, then filter, wash and dry. The obtained white powder is SBA-15. The molar ratio of each raw material used in the experiment is approximately 1 TEOS: 0.017 P123: 5.88 HCl: 136 H2O.

[0061] Mesoporous silica KIT-6 has a three-dimensional cubic ordered mesoporous structure. Its pore diameter is relatively large and can be adjusted between 4 - 12 nm. The synthesis is relatively easy. Its unique three-dimensional cubic pore channels are like an open mesoporous template, making it easy to load active species, and the loaded substances can be evenly dispersed throughout the pore channels without forming agglomerated large particles, making it have excellent structural properties and avoiding harsh conditions during synthesis. It can be obtained by anodizing crystalline silicon or amorphous silicon in hydrofluoric acid.

[0062] S2. Fill the pore structure of the template with a metal salt to obtain a first intermediate;

[0063] In some embodiments, the metal salt includes metal acetate. Further, the metal acetate includes at least one of acetates of Ni, Co, Fe, Cu, Mn, and Ag. Still further, the metal acetate includes at least two of acetates of Ni, Co, Fe, Cu, Mn, and Ag. By introducing multiple metals and utilizing the synergistic effect between different metal elements, the electronic structure of the catalytic center can be further adjusted, thereby enhancing the catalytic activity.

[0064] S3. Sinter the intermediate to convert the metal salt into a metal oxide, obtaining a second intermediate;

[0065] In some embodiments, the sintering temperature is 500 - 700 °C; the sintering time is 1 - 3 hours. Further, the sintering temperature is 550 - 650 °C; the sintering time is 1.5 - 2.5 hours. Still further, the sintering temperature is 590 - 610 °C; the sintering time is 1.9 - 2.1 hours. Exemplarily, the sintering temperature can be 500 °C, 505 °C, 510 °C, 515 °C, 520 °C, 525 °C, 530 °C, 535 °C, 540 °C, 545 °C, 550 °C, 555 °C, 560 °C, 565 °C, 570 °C, 575 °C, 580 °C, 585 °C, 590 °C, 595 °C, 600 °C, 605 °C, 610 °C, 615 °C, 620 °C, 625 °C, 630 °C, 635 °C, 640 °C, 645 °C, 650 °C, 655 °C, 660 °C, 665 °C, 670 °C, 675 °C, 680 °C, 685 °C, 690 °C, 695 °C, or 700 °C, etc., and it can also be any value within the range of 500 - 700 °C. The sintering time is 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, or 2.5 hours, etc., and it can also be any value within the range of 1.5 - 2.5 hours.

[0066] S4. Remove the template of the second intermediate to obtain a catalyst.

[0067] In some embodiments, the removal method for removing the template of the second intermediate includes etching removal. Exemplarily, the material of the template includes silicon dioxide, and the etching solution for the etching removal includes an alkali solution. Further, the alkali solution includes KOH, and the molar concentration of the KOH is 0.5 - 1.5 M. Exemplarily, the molar concentration of KOH can be 0.5 M, 0.6 M, 0.7 M, 0.8 M, 0.9 M, 1 M, 1.1 M, 1.2 M, 1.3 M, 1.4 M, or 1.5 M, etc., and it can also be any value within the range of 0.5 - 1.5 M.

[0068] This method prepares a metal oxide catalyst through a template method. The metal oxide catalyst can have the pore structure of the template. The metal oxide with such a structure has a larger specific surface area, more abundant contact sites with the electrolyte, and its ordered structure also provides a smoother path for electron transfer. Therefore, it has better catalytic performance. The entire preparation process can be carried out under normal pressure, and the raw materials for preparation are all inexpensive and environmentally friendly, having great prospects for industrial production.

[0069] Based on a general inventive concept, an embodiment of the present application also provides a catalyst, which is prepared by using the catalyst preparation method provided above.

[0070] This catalyst is prepared based on the above method. The specific steps of the method can refer to the above embodiments. Since this catalyst adopts some or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0071] Based on a general inventive concept, an embodiment of the present application also provides an application of a catalyst. The catalyst is the catalyst provided above. The application includes using the catalyst for electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural. The process of preparing 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural is as Figure 2 shown.

[0072] In some embodiments, the electrolyte for electrocatalysis includes KOH, and the molar concentration of the electrolyte is 0.5 to 1.5 mol / L. The molar concentration of 5-hydroxymethylfurfural is 0.1 to 1 mol / L. The voltage for electrocatalysis is 2 to 5V. Exemplarily, the molar concentration of the electrolyte can be 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L or 1.5 mol / L, etc., and it can also be any value within the range of 0.5 to 1.5 mol / L. The molar concentration of 5-hydroxymethylfurfural can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L or 1 mol / L, etc., and it can also be any value within the range of 0.1 to 1 mol / L. The voltage for electrocatalysis can be 2V, 3V, 4V or 5V, etc., and it can also be any value within the range of 2 to 5V.

[0073] Specifically, in this embodiment, the obtained catalyst PVDF and conductive carbon black are mixed at a mass ratio of 8:1:1, placed in an agate mortar and ground thoroughly to mix evenly. A certain amount of NMP is added, and grinding is continued for a certain time to form a uniform slurry. The slurry is evenly coated on the conductive substrate and dried thoroughly in an oven at 60 °C to obtain the loaded electrode, and the loading amount of the catalyst is 1-100 mg / cm 2 . Then, the obtained electrode is used as the anode, the Pt-loaded nickel foam is used as the cathode, Nafion115 is used as the ion exchange membrane, and the electrolyte supported by the anode and cathode is 1 mol / L KOH with a volume of 30 ml. 0.1-1 mol / L HMF is added as a reactant on the anode side. A voltage of 2-5 V is applied for electrocatalysis to obtain 2,5-furandicarboxylic acid (FDCA).

[0074] The following specific embodiments are used to further illustrate the present application. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. For the experimental methods without specific conditions indicated in the following embodiments, they are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0075] Example 1

[0076] A preparation method of a catalyst, the method comprising:

[0077] 1 g of nickel acetate and 3 g of mesoporous silica SBA-15 are added to 3 ml of ethanol, and the mixture is placed in an oven at 60 °C until the mixture is completely dried.

[0078] The mixture is ground and then heated in a muffle furnace at 600 °C for 2 h, and the product is collected.

[0079] The product is placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it is stirred for 24 h to remove the hard template. It is washed with deionized water and dried to obtain the catalyst.

[0080] Example 2

[0081] A preparation method of a catalyst, the method comprising:

[0082] 1 g of cobalt acetate and 3 g of mesoporous silica SBA-15 are added to 3 ml of ethanol, and the mixture is placed in an oven at 60 °C until the mixture is completely dried.

[0083] The mixture is ground and then heated in a muffle furnace at 600 °C for 2 h, and the product is collected.

[0084] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0085] Example 3

[0086] A method for preparing a catalyst, the method comprising:

[0087] 1 g of copper acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0088] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0089] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0090] Example 4

[0091] A method for preparing a catalyst, the method comprising:

[0092] 1 g of iron acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0093] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0094] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0095] Example 5

[0096] A method for preparing a catalyst, the method comprising:

[0097] 1 g of manganese acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0098] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0099] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0100] Example 6

[0101] A method for preparing a catalyst, the method comprising:

[0102] 1 g of silver acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0103] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0104] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0105] Example 7

[0106] A method for preparing a catalyst, the method comprising:

[0107] 1 g of nickel acetate and cobalt acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0108] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0109] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0110] Example 8

[0111] A method for preparing a catalyst, the method comprising:

[0112] 1 g of nickel acetate and copper acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0113] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0114] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0115] Example 9

[0116] A method for preparing a catalyst, the method comprising:

[0117] 1 g of nickel acetate and iron acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0118] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0119] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0120] Example 10

[0121] A method for preparing a catalyst, the method comprising:

[0122] 1 g of nickel acetate and manganese acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0123] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0124] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0125] Example 11

[0126] A method for preparing a catalyst, the method comprising:

[0127] 1 g of nickel acetate and silver acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0128] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0129] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0130] Example 12

[0131] A method for preparing a catalyst, the method comprising:

[0132] 1 g of nickel acetate, cobalt acetate and copper acetate and 3 g of mesoporous silica SBA-15 were added to 3 ml of ethanol, and the mixture was placed in an oven at 60 °C until the mixture was completely dry.

[0133] The mixture was ground and then heated in a muffle furnace at 600 °C for 2 h, and the product was collected.

[0134] The product was placed in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, it was stirred for 24 h to remove the hard template. It was washed with deionized water and dried to obtain the catalyst.

[0135] Example 13

[0136] A method for preparing a catalyst, the method comprising:

[0137] Add 1 g of nickel acetate, cobalt acetate, and manganese acetate and 3 g of mesoporous silica SBA-15 to 3 ml of ethanol, and place the mixture in an oven at 60 °C until the mixture is completely dry.

[0138] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product.

[0139] Place the product in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, stir for 24 h to remove the hard template. Wash with deionized water and dry to obtain the catalyst.

[0140] Example 14

[0141] A method for preparing a catalyst, the method comprising:

[0142] Add 1 g of nickel acetate, cobalt acetate, and silver acetate and 3 g of mesoporous silica SBA-15 to 3 ml of ethanol, and place the mixture in an oven at 60 °C until the mixture is completely dry.

[0143] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product.

[0144] Place the product in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, stir for 24 h to remove the hard template. Wash with deionized water and dry to obtain the catalyst.

[0145] Example 15

[0146] A method for preparing a catalyst, the method comprising:

[0147] Add 1 g of nickel acetate, cobalt acetate, copper acetate, and manganese acetate and 3 g of mesoporous silica SBA-15 to 3 ml of ethanol, and place the mixture in an oven at 60 °C until the mixture is completely dry.

[0148] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product.

[0149] Place the product in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, stir for 24 h to remove the hard template. Wash with deionized water and dry to obtain the catalyst.

[0150] Example 16

[0151] A method for preparing a catalyst, the method comprising:

[0152] Add 1 g of nickel acetate, cobalt acetate, copper acetate, and silver acetate and 3 g of mesoporous silica SBA-15 to 3 ml of ethanol. Place the mixture in an oven at 60 °C until the mixture is completely dry.

[0153] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product.

[0154] Place the product in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, stir for 24 h to remove the hard template. Wash with deionized water and dry to obtain the catalyst.

[0155] Example 17

[0156] A method for preparing a catalyst, the method comprising:

[0157] Add 1 g of nickel acetate, cobalt acetate, copper acetate, manganese acetate, and silver acetate and 3 g of mesoporous silica SBA-15 to 3 ml of ethanol. Place the mixture in an oven at 60 °C until the mixture is completely dry.

[0158] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product.

[0159] Place the product in 50 mL of 1 M KOH. After ultrasonic treatment for 30 min, stir for 24 h to remove the hard template. Wash with deionized water and dry to obtain the catalyst.

[0160] Comparative Example 1

[0161] A method for preparing a catalyst, the method comprising:

[0162] Add 1 g of nickel acetate to 3 ml of ethanol. Place the mixture in an oven at 60 °C until the mixture is completely dry.

[0163] Grind the mixture and then heat it in a muffle furnace at 600 °C for 2 h, and collect the product. Wash with deionized water and dry to obtain the catalyst.

[0164] Prepare the catalysts provided in the above examples and comparative examples into electrodes. The specific preparation process is as follows: Mix the catalyst, PVDF, and conductive carbon black in a mass ratio of 8:1:1, and place them in an agate mortar and grind thoroughly to mix evenly. Add a certain amount of NMP and continue to grind for a certain time to form a uniform slurry. Coat the slurry evenly on the conductive substrate and dry it thoroughly in an oven at 60 °C to obtain the loaded electrode. Then assemble the electrode into an electrolytic cell. The specific assembly process is as follows: Use the electrode prepared above as the anode, use Pt-loaded nickel foam as the cathode, use Nafion115 as the ion exchange membrane, and use 1 mol / L KOH as the electrolyte for the anode and cathode supports. The volume is 30 ml, and 0.5 mol / L HMF is added as a reactant on the anode side.

[0165] The electrolytic cell assembled with the catalyst provided in Example 12 was subjected to an electrolysis experiment. A voltage of 2 - 5 V was applied, and an electrochemical workstation was used to record the current. After the reaction ended, the solution on the anode side was taken, and the conversion rate of HMF and the yield of FDCA were analyzed using HPLC. The electrolysis used a flow-through electrolytic cell with an electrode area of 1 cm 2 . At different voltages, after electrolysis for 30 min, the conversion rate of HMF and the yield of FDCA are shown in the following table:

[0166] Voltage (V) HMF conversion rate (%) FDCA yield (%) 2 95 94 3 100 99 4 100 100 5 100 100

[0167] It can be seen from the above table that the catalytic electrolysis has a good catalytic effect when the voltage is above 2 V. Especially when the voltage is above 3 V, the conversion rate of HMF reaches 100%.

[0168] The electrolytic cells assembled with the catalysts provided in Examples 1 to 17 and Comparative Example 1 were subjected to an electrolysis experiment. A voltage of 3 V was applied, and after electrolysis for 30 min, the conversion rate of HMF and the yield of FDCA of the catalysts with different metals are shown in the following table:

[0169]

[0170]

[0171] It can be seen from the above table that the catalysts with multiple metals introduced have a better catalytic effect. It can be seen that the catalyst can further adjust the electronic structure of the catalytic center and then improve the catalytic activity by introducing multiple metals and utilizing the synergistic effect between different metal elements.

[0172] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the description of the range has specifically disclosed all possible sub-ranges and the individual values within the range. For example, it should be considered that the description of the range from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0173] In this application, unless otherwise specified, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the attached drawings. Additionally, in the description of the specification of this application, the terms "comprising", "including", etc. mean "including but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. In this text, "at least one" means one or more, and "multiple" means two or more. "At least one kind", "at least one (item) of the following", or similar expressions refer to any combination of these items, including any combination of single item (item) or plural items (items). For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0174] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a catalyst, characterized in that, The method includes: Obtaining a template, the template having a pore structure; Filling a metal salt into the pore structure of the template to obtain a first intermediate; Sintering the intermediate to convert the metal salt into a metal oxide to obtain a second intermediate; Removing the template of the second intermediate to obtain a catalyst.

2. The preparation method of the catalyst according to claim 1, characterized in that, The template includes a molecular sieve.

3. The method for preparing the catalyst according to claim 1 or 2, characterized in that, The pore structure of the template is a mesoporous structure.

4. The preparation method of the catalyst according to claim 3, characterized in that, The pore size of the pore structure of the template is 3 to 15 nanometers.

5. The preparation method of the catalyst according to claim 4, characterized in that, The material of the template includes silica.

6. The preparation method of the catalyst according to claim 5, characterized in that, The template includes at least one of SBA-15 and KIT-6.

7. The preparation method of the catalyst according to claim 1, characterized in that, The metal salt includes a metal acetate.

8. The preparation method of the catalyst according to claim 7, characterized in that, The metal acetate includes at least one of acetates of Ni, Co, Fe, Cu, Mn, and Ag.

9. The preparation method of the catalyst according to claim 8, characterized in that, The metal acetate includes at least two of acetates of Ni, Co, Fe, Cu, Mn, and Ag.

10. The preparation method of the catalyst according to claim 1, characterized in that, The temperature of the sintering is 500 to 700 °C; and / or The time of the sintering is 1 to 3 hours.

11. The preparation method of the catalyst according to claim 10, characterized in that, The temperature of the sintering is 550 to 650 °C; and / or The time of the sintering is 1.5 to 2.5 hours.

12. The preparation method of the catalyst according to claim 10, characterized in that, The temperature of the sintering is 590 to 610 °C; and / or The time of the sintering is 1.9 to 2.1 hours.

13. The preparation method of the catalyst according to claim 1, wherein, The removal method for removing the template of the second intermediate includes removal by corrosion.

14. The preparation method of the catalyst according to claim 13, characterized in that, The material of the template includes silica, and the etching solution for the removal by corrosion includes an alkali solution.

15. The preparation method of the catalyst according to claim 14, characterized in that, The alkali solution includes KOH, and the molar concentration of the KOH is 0.5 to 1.5 M.

16. A catalyst, characterized in that, The catalyst is prepared by the preparation method of the catalyst according to any one of claims 1 to 15.

17. An application of a catalyst, characterized in that, The catalyst is the catalyst according to claim 16, and the application includes using the catalyst for electrocatalytic preparation of 2,5-furandicarboxylic acid from 5-hydroxymethylfurfural.

18. Use of the catalyst according to claim 17, characterized in that, The electrolyte for the electrocatalysis includes KOH, and the molar concentration of the electrolyte is 0.5 to 1.5 mol / L.

19. Use of the catalyst according to claim 17, characterized in that, The molar concentration of the 5-hydroxymethylfurfural is 0.1 to 1 mol / L.

20. Use of the catalyst according to claim 17, characterized in that, The voltage of the electrocatalysis is 2 to 5 V.

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