Catalysts, methods of making, and uses thereof

Abstract

The application discloses a catalyst, a preparation method and application thereof, and belongs to the technical field of batteries. The catalyst provided by the application takes urea, polyethylene glycol, boric acid and nickel nitrate as reaction raw materials, and compared with a noble metal catalyst, the reaction raw materials are cheap and easy to obtain, so that the preparation cost of the catalyst can be reduced. Moreover, the catalyst can be obtained by high-temperature firing of the reaction raw materials in a tube furnace, and therefore, the preparation method of the catalyst is simple and easy to operate.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a catalyst, its preparation method, and its application. Background Technology

[0002] With the development of new energy vehicles, the discharge performance of batteries directly affects battery life, and consequently, vehicle range. 2,5-Furfurandicarboxylic acid (FDCA) can enhance battery discharge performance, and FDCA can be obtained by the catalytic oxidation of 5-hydroxymethylfurfural (HMF) in the presence of a catalyst. Therefore, the preparation of catalysts that can catalyze the conversion of HMF to FDCA is crucial.

[0003] The catalysts used in related technologies are mainly precious metal catalysts, such as platinum, gold and their alloys, but the preparation cost of precious metal catalysts is relatively high. Summary of the Invention

[0004] This application provides a catalyst, a preparation method, and its application, which can reduce the preparation cost of the catalyst. The technical solution is as follows:

[0005] On the one hand, a method for preparing a catalyst is provided, the method comprising:

[0006] Urea, polyethylene glycol, boric acid, and nickel nitrate were mixed evenly to obtain a mixture;

[0007] The mixture is placed in a crucible and fired in a tube furnace filled with argon atmosphere; wherein the firing temperature is 690~710℃ and the firing time is 130~140min.

[0008] After the firing time is reached, the temperature is maintained for 235-245 minutes to obtain the catalyst.

[0009] In one possible implementation, the urea is in the form of 11 parts by mass, the polyethylene glycol is in the form of 1 part by mass, the boric acid is in the form of 0.3 parts by mass, and the nickel nitrate is in the form of 0.005 to 0.25 parts by mass.

[0010] In another possible implementation, the mixture of urea, polyethylene glycol, boric acid, and nickel nitrate, to obtain a homogeneous mixture, comprises:

[0011] Urea solid, polyethylene glycol solid, boric acid solid and nickel nitrate solid were ground into powders respectively to obtain urea powder, polyethylene glycol powder, boric acid powder and nickel nitrate powder;

[0012] The urea powder, the polyethylene glycol powder, the boric acid powder, and the nickel nitrate powder are mixed evenly to obtain the mixture.

[0013] In another possible implementation, the mixture of urea, polyethylene glycol, boric acid, and nickel nitrate, to obtain a homogeneous mixture, comprises:

[0014] Urea solid, polyethylene glycol solid, boric acid solid and nickel nitrate solid are mixed evenly to obtain a mixed solid;

[0015] The mixed solids are ground into powder to obtain the mixture.

[0016] In another possible implementation, after reaching the firing time, the temperature is maintained for 235-245 minutes to obtain the catalyst, which includes:

[0017] After the firing time is reached, the temperature is maintained for 235-245 minutes, and then cooled to room temperature to obtain the catalyst to be cleaned.

[0018] The catalyst to be cleaned was washed multiple times with ultrapure water, and the washed catalyst was placed in a vacuum drying oven and dried at 38~42℃ for 24 hours to obtain the catalyst.

[0019] In another possible implementation, the firing temperature is 700°C.

[0020] In another possible implementation, the firing time is 135 minutes.

[0021] In another possible implementation, the polyethylene glycol has a molecular weight of 2000.

[0022] On the other hand, a catalyst is provided, which is prepared by any of the preparation methods described above.

[0023] On the other hand, the application of a catalyst prepared by any of the above methods in the catalytic conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid is provided.

[0024] This application provides a catalyst using urea, polyethylene glycol, boric acid, and nickel nitrate as reactants. Compared to precious metal catalysts, these reactants are inexpensive and readily available, thus reducing the catalyst preparation cost. Furthermore, the catalyst can be obtained by high-temperature calcination of the aforementioned reactants in a tube furnace, demonstrating that the catalyst preparation method is simple and easy to operate.

[0025] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application.

[0026] Figure Labels

[0027] Figure 1 This is a flowchart of a catalyst preparation method provided in an embodiment of this application;

[0028] Figure 2 This is a schematic diagram illustrating the conversion of HMF to FDCA according to an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of an LSV curve provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of an LSV curve provided in an embodiment of this application. Detailed Implementation

[0031] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0032] Currently, the main methods for converting HMF to FDCA are as follows:

[0033] The first method is direct oxidation. This involves using a strong oxidizing agent to oxidize HMF to FDCA. For example, hydrogen peroxide could be used as an oxidizing agent. However, this method generates byproducts, and the resulting FDCA has low purity, increasing subsequent separation costs.

[0034] The second method is biocatalysis. This method uses enzyme catalysis or whole-cell catalysis to promote the reaction. It is usually carried out in a relatively mild environment and can catalyze waste into useful renewable resources, which is very much in line with the current concept of green environmental protection.

[0035] The third method is electrocatalysis. Electrocatalysis is driven by an applied potential, therefore, it does not require the addition of strong oxidants or enzymes to catalyze the conversion of HMF to FDCA. Electrocatalysis boasts numerous significant advantages, including being environmentally friendly, highly controllable, and suitable for specific reaction conditions and temperatures, making it a highly promising technological approach. Its environmentally friendly characteristics reduce the generation of harmful substances during the catalytic process, which is of great significance for environmental protection.

[0036] The catalyst prepared in this application catalyzes the conversion of HMF to FDCA via electrocatalysis. The preparation method of the catalyst provided in this application is described below.

[0037] This application provides a method for preparing a catalyst, see [link to relevant documentation]. Figure 1 The preparation method includes:

[0038] Step 101: Mix urea, polyethylene glycol, boric acid and nickel nitrate evenly to obtain a mixture.

[0039] This step can be achieved in any of the following ways.

[0040] In the first method, solid urea, solid polyethylene glycol, solid boric acid, and solid nickel nitrate are ground into powders to obtain urea powder, polyethylene glycol powder, boric acid powder, and nickel nitrate powder; the urea powder, polyethylene glycol powder, boric acid powder, and nickel nitrate powder are then mixed evenly to obtain a mixture.

[0041] The second method involves uniformly mixing solid urea, polyethylene glycol, solid boric acid, and solid nickel nitrate to obtain a mixed solid; then grinding the mixed solid into powder to obtain a mixture.

[0042] In the embodiments of this application, the mass fraction of urea is 11 parts, the mass fraction of polyethylene glycol is 1 part, the mass fraction of boric acid is 0.3 parts, and the mass fraction of nickel nitrate is 0.005~0.25 parts.

[0043] The mass fractions of nickel nitrate can be 0.005, 0.01, 0.02, 0.03, 0.04, 0.08, 0.1, 0.12, 0.15, 0.18, 0.2, 0.22, or 0.25 parts.

[0044] The molecular weight of polyethylene glycol can be selected as needed and is not specifically limited. For example, the molecular weight of polyethylene glycol can be 2000 or 4000. In the embodiments of this application, only a molecular weight of 2000 polyethylene glycol is used as an example for illustration.

[0045] One point to note is that before this step, you can first put the solid urea, solid polyethylene glycol, solid boric acid, and solid nickel nitrate into a separate container, then add a certain volume of ultrapure water to each container, wash them with ultrapure water, and then put them into a drying oven to dry. After drying, proceed to step 101.

[0046] The volume of ultrapure water can be set and changed as needed, without any specific limitation. For example, the volume of ultrapure water is 50 mL.

[0047] The temperature of the forced-air drying oven can be set and changed as needed, without any specific limitation. For example, the temperature of the forced-air drying oven can be 80℃.

[0048] The drying time can also be set and changed as needed, without any specific limitation. For example, the drying time can be 24 hours.

[0049] Step 102: Place the mixture in a crucible and calcine it in a tube furnace filled with argon atmosphere.

[0050] The mixture is placed in a crucible and fired in a tube furnace filled with argon at a temperature of 690-710°C for 130-140 minutes.

[0051] The firing temperature can be 690℃, 695℃, 700℃, 705℃, or 710℃, and the firing time can be 130min, 132min, 135min, 138min, or 140min. In this embodiment, only a firing temperature of 700℃ and a firing time of 135min are used as an example for illustration.

[0052] In the embodiments of this application, urea, polyethylene glycol, boric acid, and nickel nitrate react at high temperature to generate a catalyst, which can be represented as Ni / BNC. However, if the firing temperature is too high or too low, or the firing time is too long or too short, the catalyst provided in this application cannot be generated.

[0053] Step 103: After the firing time is reached, keep warm for 235~245 minutes to obtain the catalyst.

[0054] After the calcination time is reached, the temperature is maintained for 235-245 minutes, and then cooled to room temperature to obtain the catalyst to be cleaned. The catalyst to be cleaned is washed multiple times with ultrapure water, and the washed catalyst is placed in a vacuum drying oven and dried at 38-42℃. After 24 hours, it is taken out to obtain the catalyst.

[0055] The heat preservation time can be 235 min, 238 min, 240 min, 242 min, or 245 min. In this embodiment, only a heat preservation time of 240 min is used as an example for illustration.

[0056] The drying temperature of the vacuum drying oven can be 38℃, 39℃, 40℃, 41℃, or 42℃. In this embodiment, only a drying temperature of 40℃ is used as an example for illustration.

[0057] The number of washes can be set and changed as needed, without any specific limit. For example, the number of washes can be 3, 4, or 5.

[0058] In the embodiments of this application, after obtaining the catalyst, the catalyst can be placed in a sample vial and taken out when needed for subsequent use.

[0059] This application provides a catalyst using urea, polyethylene glycol, boric acid, and nickel nitrate as reactants. Compared to precious metal catalysts, these reactants are inexpensive and readily available, thus reducing the catalyst preparation cost. Furthermore, the catalyst can be obtained by high-temperature calcination of the aforementioned reactants in a tube furnace, demonstrating that the catalyst preparation method is simple and easy to operate.

[0060] On the other hand, embodiments of this application provide a catalyst prepared using the above-described preparation method.

[0061] On the other hand, embodiments of this application provide an application of a catalyst in the catalytic conversion of HMF to FDCA.

[0062] It should be noted that there are two main paths for converting HMF to FDCA: the first is HMF→DFF→FFCA→FDCA, and the second is HMF→HMFCA→FFCA→FDCA. (See [link to relevant documentation]). Figure 2 The catalyst prepared in this application mainly catalyzes the conversion of HMF to FDCA via the second pathway. That is, under the catalytic action of the catalyst, HMF is first converted to HMFCA, then to FFCA, and finally to FDCA.

[0063] Exemplary embodiments of this application will now be described in more detail. While exemplary embodiments of this application are described below, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein.

[0064] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0065] Example 1

[0066] Step 1: Weigh 11g of urea, 1g of PEG-2000 (polyethylene glycol), 0.3g of boric acid and 15mg of nickel nitrate, mix them evenly, and then grind them into powder to obtain a mixture.

[0067] Step 2: Place the mixture in a crucible and fire it in a tube furnace filled with argon atmosphere at a temperature of 700°C for 135 minutes.

[0068] Step 3: After the calcination time is reached, keep warm for 240 minutes, cool down to room temperature, and obtain the catalyst to be cleaned; wash the catalyst to be cleaned multiple times with ultrapure water, put the washed catalyst into a vacuum drying oven, dry at 40℃, take it out after 24 hours, and obtain the catalyst, which is labeled as Ni / BNC-15mg.

[0069] Example 2

[0070] Step 1: Weigh 11g of urea, 1g of PEG-2000 (polyethylene glycol), 0.3g of boric acid and 30mg of nickel nitrate, mix them evenly, and then grind them into powder to obtain a mixture.

[0071] Step 2: Place the mixture in a crucible and fire it in a tube furnace filled with argon atmosphere at a temperature of 700°C for 135 minutes.

[0072] Step 3: After the calcination time is reached, keep warm for 240 minutes, cool down to room temperature, and obtain the catalyst to be cleaned; wash the catalyst to be cleaned multiple times with ultrapure water, put the washed catalyst into a vacuum drying oven, dry at 40℃, take it out after 24 hours, and obtain the catalyst, which is labeled as Ni / BNC-30mg.

[0073] Example 3

[0074] Step 1: Weigh 11g of urea, 1g of PEG-2000 (polyethylene glycol), 0.3g of boric acid and 60mg of nickel nitrate, mix them evenly, and then grind them into powder to obtain a mixture.

[0075] Step 2: Place the mixture in a crucible and fire it in a tube furnace filled with argon atmosphere at a temperature of 700°C for 135 minutes.

[0076] Step 3: After the calcination time is reached, keep warm for 240 minutes, cool down to room temperature, and obtain the catalyst to be cleaned; wash the catalyst to be cleaned multiple times with ultrapure water, put the washed catalyst into a vacuum drying oven, dry at 40℃, take it out after 24 hours, and obtain the catalyst, which is labeled as Ni / BNC-60mg.

[0077] Example 4

[0078] Step 1: Weigh 11g of urea, 1g of PEG-2000 (polyethylene glycol), 0.3g of boric acid and 120mg of nickel nitrate, mix them evenly, and then grind them into powder to obtain a mixture.

[0079] Step 2: Place the mixture in a crucible and fire it in a tube furnace filled with argon atmosphere at a temperature of 700°C for 135 minutes.

[0080] Step 3: After the calcination time is reached, keep warm for 240 minutes, then cool down to room temperature to obtain the catalyst to be cleaned; wash the catalyst to be cleaned multiple times with ultrapure water, put the washed catalyst into a vacuum drying oven, dry at 40°C, and take it out after 24 hours to obtain the catalyst, which is labeled as Ni / BNC-120mg.

[0081] In Examples 1-4 of this application, catalysts were prepared using nickel nitrate, polyethylene glycol, boric acid, and urea as precursors. The mass fractions of urea, polyethylene glycol, and boric acid were fixed using the controlled variable method, while the mass fraction of nickel nitrate was varied. The catalysts were then loaded onto carbon paper to explore their effect on the electrocatalytic oxidation of HMF to FDCA, and the discharge performance of the battery was then tested.

[0082] Test Example 1

[0083] Take 5 mg of catalyst and add 960 μL of isopropanol solution and 40 μL of Nafion solution (perfluorosulfonic acid polymer solution). Use an ultrasonic cleaner to perform ultrasonication for 30 min at a water temperature of less than 30°C to achieve uniform dispersion.

[0084] Use a pipette to transfer 50 μL of catalyst solution and evenly drop the catalyst solution onto the surface of a 1.5 cm × 1.5 cm carbon paper, leaving a 1.5 cm × 1 cm area for easy handling. Then place it at room temperature and let it dry for about 45 minutes to obtain a positive electrode that meets the research requirements.

[0085] Taking the catalyst prepared in Example 2 as an example, after preparing the positive electrode according to the above method, the positive electrode was immersed in a 1 mol / L KOH solution, and the platinum sheet was immersed in a 1 mol / L KOH solution as the negative electrode. A linearly changing potential was applied to the working electrode by linear sweep voltammetry (LSV), and the corresponding current change was monitored and recorded in real time, thereby generating a current-potential curve. Figure 3 The curve corresponding to KOH.

[0086] The positive electrode was immersed in a 5 mmol / L HMF solution, and the platinum sheet, used as the negative electrode, was immersed in a 1 mol / L KOH solution. A linearly changing potential was applied to the working electrode using linear sweep voltammetry (LSV), and the corresponding current changes were monitored and recorded in real time, thus generating a current-potential curve. This curve is... Figure 3 Curve 3 corresponds to HMF in the middle.

[0087] By analyzing this curve, the onset potential can be determined (the onset potential is the value of the intersection of the tangent line of the LSV curve and the x-axis). The onset potential directly reflects the thermodynamic barrier faced by the catalyst during the HMF oxidation process. A lower onset potential means that the catalyst can more easily overcome the energy barrier required for the reaction, thus exhibiting stronger discharge performance.

[0088] from Figure 3 It can be seen that when HMF solution is used, the onset potential of Ni / BNC shifts significantly in the negative direction, which indicates that the HMF oxidation reaction is thermodynamically more favorable than the oxidation reaction of water.

[0089] For the catalysts prepared in Examples 1-3, after preparing the positive electrode according to the above method, the positive electrode was immersed in a 5 mmol / L HMF solution, and the platinum sheet was used as the negative electrode and immersed in a 1 mol / L KOH solution. The performance of the catalyst in catalyzing the HMF oxidation reaction was tested by linear sweep voltammetry (LSV).

[0090] See Figure 4 , Figure 4 The LSV curves were obtained based on the catalysts prepared in Examples 1-4. Figure 4 As can be seen, the initiation potentials of Ni / BNC-15mg, Ni / BNC-30mg, Ni / BNC-60mg, and Ni / BNC-120mg all showed a significant negative shift. Among them, the curve corresponding to Ni / BNC-120mg had the smallest slope and the gentlest gradient, indicating that it had the lowest initiation potential and thus the strongest discharge performance.

[0091] Test Example 2

[0092] High-performance liquid chromatography (HPLC) was used to quantitatively analyze the samples and compare the effects of various catalysts on the electrocatalytic oxidation of HMF to FDCA. Before and after the electrocatalytic reaction, 10 μL of electrolyte containing reactants and products was extracted and analyzed by HPLC. The yield of FDCA can be expressed by the following formula:

[0093] .

[0094] Based on the relevant data, calculations show that the FDCA yields for Ni / BNC-15mg, Ni / BNC-30mg, Ni / BNC-60mg, and Ni / BNC-120mg are 0.1%, 1.91%, 1.68%, and 3.01%, respectively. This indicates that Ni / BNC-120mg has the highest FDCA yield, demonstrating its strongest discharge performance, consistent with the conclusion drawn from Test Example 1.

[0095] In summary, the catalyst prepared in this application using nickel nitrate, polyethylene glycol, boric acid, and urea as precursors can indeed catalyze the conversion of HMF to FDCA, thereby enhancing the discharge performance of the battery. Furthermore, the catalyst prepared in this application is low in cost and the preparation method is simple and easy to operate.

[0096] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a catalyst, characterized in that, The preparation method includes: Urea, polyethylene glycol, boric acid, and nickel nitrate are mixed evenly to obtain a mixture; wherein the mass fraction of solid urea is 11 parts, the mass fraction of solid polyethylene glycol is 1 part, the mass fraction of solid boric acid is 0.3 parts, and the mass fraction of solid nickel nitrate is 0.005~0.25 parts. The mixture is placed in a crucible and fired in a tube furnace filled with argon atmosphere; wherein the firing temperature is 690~710℃ and the firing time is 130~140min. After the firing time is reached, the temperature is maintained for 235-245 minutes, and then cooled to room temperature to obtain the catalyst to be cleaned. The catalyst to be cleaned was washed multiple times with ultrapure water. The washed catalyst was then placed in a vacuum drying oven and dried at 38-42°C for 24 hours to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that, The mixture of urea, polyethylene glycol, boric acid, and nickel nitrate is homogeneous, yielding a mixture comprising: Urea solid, polyethylene glycol solid, boric acid solid and nickel nitrate solid were ground into powders respectively to obtain urea powder, polyethylene glycol powder, boric acid powder and nickel nitrate powder; The urea powder, the polyethylene glycol powder, the boric acid powder, and the nickel nitrate powder are mixed evenly to obtain the mixture.

3. The preparation method according to claim 1, characterized in that, The mixture of urea, polyethylene glycol, boric acid, and nickel nitrate is homogeneous, yielding a mixture comprising: Urea solid, polyethylene glycol solid, boric acid solid and nickel nitrate solid are mixed evenly to obtain a mixed solid; The mixed solids are ground into powder to obtain the mixture.

4. The preparation method according to claim 1, characterized in that, The firing temperature is 700℃.

5. The preparation method according to claim 1, characterized in that, The firing time is 135 minutes.

6. The preparation method according to claim 1, characterized in that, The molecular weight of the polyethylene glycol is 2000.

7. A catalyst, characterized in that, The catalyst is prepared using the preparation method described in any one of claims 1 to 6.

8. The use of a catalyst prepared by any one of claims 1 to 6 in the catalytic conversion of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid.

Images