Preparation method and application of a monolithic cobalt-doped nickel-molybdenum nanowire catalyst

Abstract

The application discloses a preparation method and application of a monolithic cobalt-doped nickel-molybdenum nanowire catalyst, the catalyst comprising a carrier and an active substance in-situ grown on the carrier; the active substance comprising cobalt elements, nickel elements and molybdenum elements. The preparation method comprises the following steps: 1. generating a precursor on the carrier through a hydrothermal reaction; 2. performing in-situ electrochemical activation on the precursor to obtain the monolithic cobalt-doped nickel-molybdenum nanowire catalyst. The monolithic cobalt-doped nickel-molybdenum nanowire catalyst provided by the application has high stability and long service life, has rich pore structure and large aspect ratio nanowire morphology, and improves the mass transfer and charge transfer rate. Compared with a nanometer powder catalyst, the catalyst provided by the application is easy to separate from products after reaction, and can be repeatedly used for multiple times. The catalyst can be applied to the fields of chemical industry, environmental protection and biomass conversion, and is particularly suitable for large-current biomass electrocatalytic reactions.

Description

TECHNICAL FIELD

[0001] The application relates to a monolithic cobalt-doped nickel-molybdenum nanowire catalyst and a preparation method and application thereof, and belongs to the technical field of catalysis. BACKGROUND

[0002] At present, catalysts are widely used in chemical production to accelerate the reaction rate and improve the selectivity of target products. Traditional noble metal catalysts such as gold, platinum and ruthenium are expensive, which limits their large-scale industrial application. Transition metals such as nickel, cobalt and molybdenum not only have good catalytic performance, but also have abundant reserves and low price, and are expected to replace noble metal catalysts and be applied to the field of electrocatalysis. The performance of the electrocatalyst depends largely on its geometric morphology, active defects and electronic energy band distribution. Through catalyst structure design and surface interface engineering treatment, the mass transfer channel of the catalyst can be constructed, and the electronic structure and band gap of the catalyst can be adjusted, so that the catalytic performance can be greatly improved, and the service life of the catalyst can be prolonged. Patent CN202010687438.7 discloses a noble metal / nickel-molybdenum-based composite hydrogen evolution electrocatalyst, which can realize large current density hydrogen evolution reaction, but the use of noble metal increases the use cost of the catalyst. Patent CN202010032065.X discloses a hydrogen evolution electrocatalyst taking nickel molybdate-nickel nitride as an active component and foamed nickel as a carrier, which adopts a doping strategy and constructs a heterojunction to improve the conductivity and activity of the catalyst, but the preparation process involves a high-temperature calcination and annealing step, which is complicated and has low controllability, and is not conducive to large-scale industrialization. The nickel-molybdenum-based catalysts involved at present have single catalytic performance, and can only improve the cathode hydrogen evolution reaction rate. In order to improve the energy utilization efficiency of the electrolysis system, the anode reaction rate needs to be improved by developing catalysts, but the use of multiple catalysts increases the cost of the electrolysis system. Therefore, obtaining a multifunctional electrocatalyst with high activity, selectivity and stability is of great significance for the industrial application of electrocatalytic reaction. SUMMARY

[0003] To solve the above technical problems, the application provides a preparation method and application of a monolithic cobalt-doped nickel-molybdenum nanowire bifunctional catalyst. The catalyst precursor after hydrothermal reaction is subjected to simple activation treatment, the molybdenum element in the nanowire is partially dissolved to construct rich pores, more mass transfer channels are provided for reaction molecules, and the specific surface area of the electrocatalytic activity is improved. Secondly, the doping of the variable valence metal cobalt can adjust the electronic structure of the active site, improve the reaction activity and reduce the overpotential required for biomass electrocatalytic conversion. The monolithic catalyst has high catalytic activity and stable performance, and the preparation method is simple and low in cost.

[0004] The monolithic cobalt-doped nickel-molybdenum nanowire catalyst comprises a carrier and an active substance grown in situ on the carrier.

[0005] The active substance comprises cobalt elements, nickel elements and molybdenum elements.

[0006] The content of cobalt element is 1-10wt%, the content of nickel element is 50-80wt%, and the content of molybdenum element is 10-30wt%

[0007] The content of each element is in percentage of mass.

[0008] The carrier is not particularly limited in the present application. In order to prepare a uniform catalyst and improve the catalytic efficiency, the carrier is selected from any one of foamed metal, carbon fiber cloth, and sheet metal, so that the carrier can be laid flat or stand on the bottom of a reaction kettle.

[0009] Optionally, the active substance has a needle-like nanowire morphology on the carrier.

[0010] Optionally, the nanowire has a diameter of 50-100nm and a length of 200-800nm.

[0011] According to another aspect of the present application, a preparation method of the monolithic cobalt-doped nickel-molybdenum nanowire catalyst is provided, which comprises at least the following steps:

[0012] Step 1, hydrothermal reaction of a mixture containing a cobalt source, a nickel source, and a molybdenum source with a carrier to obtain a catalyst precursor;

[0013] Step 2, electrochemical activation of the catalyst precursor to obtain the monolithic cobalt-doped nickel-molybdenum nanowire catalyst.

[0014] Optionally, the method further comprises pretreatment of the carrier.

[0015] Specifically, the carrier pretreatment method is as follows:

[0016] The carrier is immersed in 0.1-2M hydrochloric acid for ultrasonic treatment for 10-30min, and then taken out and cleaned with anhydrous ethanol and deionized water for 10-20min to obtain the carrier with impurities removed.

[0017] Specifically, step 1 comprises:

[0018] The cobalt source, the nickel source, the molybdenum source, and the solvent are mixed uniformly, and the carrier is added to prepare the catalyst precursor by hydrothermal reaction.

[0019] Optionally, the cobalt source is selected from at least one of cobalt nitrate hexahydrate, cobalt sulfate, cobalt chloride hexahydrate, and cobalt acetate tetrahydrate;

[0020] The nickel source is selected from at least one of nickel nitrate hexahydrate, nickel acetate tetrahydrate, nickel chloride hexahydrate, and nickel sulfate hexahydrate;

[0021] The molybdenum source is selected from at least one of sodium molybdate dihydrate and ammonium molybdate tetrahydrate.

[0022] Specifically, in the embodiments of the present application, the cobalt source is selected from at least one of cobalt nitrate hexahydrate and cobalt chloride hexahydrate;

[0023] The nickel source is selected from at least one of nickel acetate tetrahydrate and nickel sulfate hexahydrate;

[0024] The molybdenum source is selected from at least one of nickel acetate tetrahydrate and nickel sulfate hexahydrate.

[0025] Optionally, in step 1, the molar ratio of the cobalt source to the nickel source in the mixture is 1:5-1:100, and the molar ratio of the molybdenum source to the nickel source is 1:5-1:50, based on the moles of each substance itself.

[0026] Preferably, the molar ratio of the cobalt source to the nickel source in the mixture is 1:5-1:80, and the molar ratio of the molybdenum source to the nickel source is 1:5-1:20.

[0027] Specifically, the lower limit of the molar ratio of the cobalt source to the nickel source in the mixture can be independently selected from 1:5, 1:10, 1:20, 1:30, 1:40, and 1:50, and the upper limit of the molar ratio of the cobalt source to the nickel source can be independently selected from 1:60, 1:70, 1:80, 1:90, and 1:100.

[0028] Specifically, the lower limit of the molar ratio of the molybdenum source to the nickel source in the mixture can be independently selected from 1:5, 1:8, 1:10, 1:15, 1:20, and 1:25, and the upper limit of the molar ratio of the molybdenum source to the nickel source can be independently selected from 1:30, 1:35, 1:40, 1:45, and 1:50.

[0029] Optionally, in step 1, the mixture further comprises a solvent;

[0030] In the present application, the concentration of each substance in the mixture is not particularly limited. In order to prepare a cobalt-doped nickel-molybdenum nanowire catalyst with excellent performance, enhance the stability of the catalyst, and improve the service life, the molar ratio of the cobalt source to the solvent in the mixture is 1:2000-1:12000.

[0031] Preferably, the solvent comprises water.

[0032] Specifically, the lower limit of the molar ratio of the cobalt source to the solvent can be independently selected from 1:2000, 1:3000, 1:4000, 1:5000, and 1:6000, and the upper limit of the molar ratio of the cobalt source to the solvent can be independently selected from 1:7000, 1:8000, 1:9000, 1:10000, and 1:12000.

[0033] Optionally, in step 1, the hydrothermal reaction is carried out under the following conditions:

[0034] The reaction temperature is 110°C-200°C, and the reaction time is 2h-15h.

[0035] Preferably, the reaction temperature is 140° C. to 160° C., and the reaction time is 10 h to 15 h.

[0036] Specifically, the lower limit of the reaction temperature can be independently selected from 110°C, 115°C, 120°C, 125°C, and 130°C; the upper limit of the reaction temperature can be independently selected from 140°C, 150°C, 160°C, 180°C, and 200°C.

[0037] Specifically, the lower limit of the reaction time can be independently selected from 2 h, 3 h, 4 h, 5 h, and 6 h; the lower limit of the reaction time can be independently selected from 8 h, 10 h, 12 h, 14 h, and 15 h.

[0038] Optionally, step 2 includes:

[0039] In an electrolytic cell containing an alkaline solution, the catalyst precursor is used as an anode to perform in-situ electrochemical activation to obtain the monolithic cobalt-doped nickel-molybdenum nanowire catalyst;

[0040] Preferably, the alkaline solution is at least one of sodium hydroxide and potassium hydroxide solution;

[0041] Preferably, the concentration of hydroxide in the alkaline solution is 0.1M to 3M.

[0042] Optionally, in step 2, the conditions for the electrochemical activation are:

[0043] The activation voltage is 0.8~2V, and the activation current density is 1~100mA / cm 2 , activation time is 1 to 30 hours.

[0044] Preferably, the activation voltage is 1-1.5 V and the activation current density is 10-50 mA / cm 2 , activation time is 2 to 5 hours.

[0045] In a specific embodiment, the electroactivation process is performed by activation at a constant voltage until the current reaches a steady state or activation at a constant current density until the potential reaches a steady state.

[0046] Specifically, the lower limit of activation voltage can be independently selected from 0.8V, 0.9V, 1V, the upper limit of activation voltage can be independently selected from 1.5V, 1.6V, 1.7V, 1.8V, 1.9V, 2.0V; the lower limit of activation current density can be independently selected from 1mA / cm 2 , 5mA / cm 2 , 10mA / cm 2 , 20mA / cm 2 、30mA / cm 2 , the upper limit of activation current density can be independently selected from 50mA / cm2 , 60 mA / cm 2 , 70 mA / cm 2 , 90 mA / cm 2 , 100 mA / cm 2 .

[0047] Specifically, the lower limit of the activation time can be independently selected from 1 h, 2 h, 5 h, 10 h, 13 h, and the upper limit of the activation time can be independently selected from 15 h, 17 h, 20 h, 25 h, 30 h.

[0048] Optionally, the method further comprises: washing and drying the catalyst precursor.

[0049] The drying condition is that the drying temperature is 50-100°C, and the drying time is 5-12 h.

[0050] A small amount of solid is attached to the surface of the precursor obtained by the reaction, and washing operation is required to remove the solid. Preferably, the washing method is that the precursor is washed with water and ethanol for 2-3 times in sequence.

[0051] After the washing operation of the catalyst precursor, drying treatment is performed to remove the residual water and ethanol of the precursor.

[0052] Specifically, the lower limit of the drying temperature can be independently selected from 50°C, 55°C, 60°C, 65°C, 70°C, and the upper limit of the drying temperature can be independently selected from 75°C, 80°C, 85°C, 90°C, 100°C.

[0053] Specifically, the drying time can be independently selected from 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h, or any point value between the above two points.

[0054] According to another aspect of the present application, the application provides the use of the whole cobalt-doped nickel-molybdenum nanowire catalyst.

[0055] A method for preparing 2,5-furan dicarboxylic acid, characterized in that the method at least comprises:

[0056] The solution containing the reaction substrate is reacted under the action of the catalyst to obtain 2,5-furan dicarboxylic acid;

[0057] The reaction substrate is selected from at least one of 2,5-furan dimethanol, 5-hydroxymethyl furfural, 2,5-furan dicarboxaldehyde, 5-hydroxymethyl-2-furan carboxylic acid, and 5-formyl-2-furan carboxylic acid;

[0058] The catalyst is selected from at least one of any of the above whole cobalt-doped nickel-molybdenum nanowire catalysts and the whole cobalt-doped nickel-molybdenum nanowire catalysts prepared by any of the above methods.

[0059] Optionally, the method comprises:

[0060] The 2,5-furan dicarboxylic acid is obtained by performing an electrochemical reaction with the catalyst as a working electrode and the reaction substrate as a raw material.

[0061] Specifically, the method is:

[0062] The 2,5-furan dicarboxylic acid is obtained by performing a constant voltage reaction with the catalyst as a working electrode, a carbon rod as a counter electrode, mercury / mercury oxide as a reference electrode, 1M KOH as an electrolyte, and the reaction substrate as a raw material to construct a reaction system.

[0063] Optionally, the electrochemical reaction condition is:

[0064] The reaction voltage is 1-3V, and the reaction time is 0.5-5h.

[0065] Specifically, the reaction voltage can be independently selected from 1V, 1.5V, 2V, 2.5V, 3V, or any value between the above two points.

[0066] Specifically, the reaction time can be independently selected from 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, or any value between the above two points.

[0067] The beneficial effects that can be produced by the present application include:

[0068] 1) The overall cobalt-doped nickel-molybdenum nanowire catalyst provided by the present application has high stability and long service life. During preparation, after the precursor is subjected to simple electrochemical activation treatment, part of the molybdenum element on the surface of the nanowire is dissolved to construct rich pores, thereby improving the electrocatalytic activity specific surface area. Secondly, the nanowire obtained through structural design has a large aspect ratio structure, thereby having better electronic conductivity and surface contact ability, improving the mass transfer and charge transfer rate, and being able to meet the large current density requirement required in actual production.

[0069] 2) The overall cobalt-doped nickel-molybdenum nanowire catalyst provided by the present application only needs to pass through the hydrothermal and electrochemical activation steps, without subsequent high-temperature calcination treatment, thereby reducing the preparation energy consumption; the raw materials are cheap and easy to obtain, the catalyst can be prepared on a large scale, and the requirements for equipment and technology are low. Compared with the nanometer powder catalyst, it is easy to separate from the product during catalytic reaction, and can be repeatedly used.

[0070] 3) The whole cobalt-doped nickel-molybdenum nanowire catalyst provided by the present application is used for anodic electrocatalytic oxidation of 2,5-furandimethanol, 5-hydroxymethylfurfural, 2,5-furandicarboxaldehyde, 5-hydroxymethyl-2-furancarboxylic acid, and 5-formyl-2-furancarboxylic acid to prepare 2,5-furandicarboxylic acid, and has stable catalytic performance and good hydrogen evolution performance, so it can be used as a bifunctional catalyst to simultaneously perform biomass oxidation reaction and hydrogen evolution reaction, thereby greatly improving the utilization efficiency of input energy. In addition, the catalyst can also be applied to other organic small molecule electrocatalytic reactions. BRIEF DESCRIPTION OF DRAWINGS

[0071] Figure 1 is a scanning electron microscope image of the whole cobalt-doped nickel-molybdenum nanowire catalyst precursor prepared in Example 1;

[0072] Figure 2 is a scanning electron microscope image of the whole cobalt-doped nickel-molybdenum nanowire catalyst prepared in Example 1;

[0073] Figure 3 is a scanning electron microscope image of the whole cobalt-doped nickel-molybdenum nanowire catalyst prepared in Examples 1-3, wherein Figure a is a scanning electron microscope image of the catalyst precursor obtained in Example 1, Figure b is a scanning electron microscope image of the catalyst precursor obtained in Example 2, and Figure c is a scanning electron microscope image of the catalyst precursor obtained in Example 3;

[0074] Figure 4 is a transmission electron microscope image of the whole cobalt-doped nickel-molybdenum nanowire catalyst prepared in Example 1, wherein Figures a and b are transmission electron microscope images at different magnifications;

[0075] Figure 5 is a polarization curve of the catalyst prepared in Example 1 as an electrocatalytic electrode in a solution containing 100 mM 2,5-furandimethanol and 1 M potassium hydroxide;

[0076] Figure 6 is a high-performance liquid chromatogram of each substance in the reaction process of Example 8;

[0077] Figure 7 is a graph of the conversion rate of the reactant and the yield of the product with time in the reaction of Example 8. DETAILED DESCRIPTION

[0078] The present application will be described in detail below in conjunction with examples, but the present application is not limited to these examples.

[0079] In the following examples, the experimental methods used are conventional methods unless otherwise specified; the reagents, materials, etc. used in the following examples can be obtained from commercial channels unless otherwise specified. In the following examples, the parameters used in the use process are all the parameters recommended by the manufacturer unless otherwise specified.

[0080] The instruments and parameters used in the sample characterization analysis in the examples are as follows:

[0081] SEM measurements were performed using a HITACHI S-4800 scanning electron microscope at 8.0 kV.

[0082] SEM-EDX measurements were performed using a HITACHI S-4800 scanning electron microscope at 20.0 kV.

[0083] TEM analysis was performed using a JEOL 2100 transmission electron microscope at 200 kV.

[0084] Catalyst activation and catalytic reactions were carried out using a Chenhua CHI 760E electrochemical workstation.

[0085] Agilent high performance liquid chromatography was used for quantitative analysis of reactants, intermediates, and products.

[0086] Example 1

[0087] (1) Add 0.15 g of cobalt nitrate hexahydrate, 1.493 g of nickel acetate tetrahydrate, 1.235 g of ammonium molybdate tetrahydrate, and 60 mL of deionized water into a beaker and stir magnetically at room temperature for half an hour to obtain a green uniform mixed solution.

[0088] (2) The mixed solution prepared in step (1) was transferred to a 100 mL hydrothermal reactor, and two pieces of nickel foam carriers with a size of 1 cm*3 cm were added, and they were laid flat or placed sideways on the bottom of the reactor. The reactor was placed in an oven and reacted at 140°C for 5 hours. After the reaction was completed and cooled to room temperature naturally, the precursor was taken out and rinsed with water and ethanol three times in sequence. The washed precursor was placed in a beaker and placed in an oven and dried at 60°C for 12 hours. The precursor was characterized by SEM, and the results were as follows: Figure 1 shown.

[0089] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , 10mA / cm 2 Under constant current activation conditions for 2 h, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 1.

[0090] The obtained catalyst was characterized by EDX, and the results are shown in Table 1. The percentage content of each element on the catalyst surface is Co (1.57At%), Mo (13.60At%), O (22.31At%), and Ni (62.52At%), respectively. The above results prove that a cobalt-doped nickel-molybdenum-based catalyst was successfully obtained.

[0091] Table 1

[0092]

[0093] Example 2

[0094] The specific operations of steps (1) and (2) are the same as those in Example 1.

[0095] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , 10mA / cm 2 After 5 h of constant current activation, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 2.

[0096] Example 3

[0097] The specific operations of steps (1) and (2) are the same as those in Example 1.

[0098] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm -2 , 10mA / cm 2 After 30 h of constant current activation, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 3.

[0099] Example 4

[0100] The specific operations of steps (1) and (2) are the same as those in Example 1.

[0101] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , 50mA / cm 2 Under constant current activation conditions for 5 h, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 4.

[0102] Example 5

[0103] (1) Add 0.09438 g of cobalt chloride hexahydrate, 1.577 g of nickel sulfate hexahydrate, 0.24195 g of sodium molybdate dihydrate, and 60 mL of deionized water into a beaker and stir magnetically at room temperature for half an hour to obtain a green homogeneous solution.

[0104] (2) The mixed solution prepared in step (1) was transferred to a 100 mL hydrothermal reactor, and two pieces of nickel foam carriers with a size of 1 cm*3 cm were added and laid flat or placed sideways on the bottom of the reactor. The reactor was placed in an oven and reacted at 140°C for 5 h. After the reaction was completed and naturally cooled to room temperature, the precursor was taken out and rinsed with water and ethanol three times in sequence. The washed precursor was placed in a beaker and placed in an oven and dried at 60°C for 12 h.

[0105] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , 10mA / cm 2 Under constant current activation conditions for 2 h, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 5.

[0106] Example 6

[0107] The specific operations of steps (1) and (2) are the same as those in Example 5.

[0108] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , 20mA / cm 2 Under constant current activation conditions for 1 h, a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam was obtained, which was recorded as sample 6.

[0109] Example 7

[0110] The specific operations of steps (1) and (2) are the same as those in Example 5.

[0111] (3) The precursor obtained in step (2) was used as the anode, the carbon rod as the cathode, mercury / mercuric oxide as the reference electrode, and 1M potassium hydroxide as the electrolyte to form a three-electrode system. The precursor was immersed in the electrolyte for 1 cm 2 , and activated at a constant voltage of 1.5 V for 2 h to obtain a monolithic cobalt-doped nickel-molybdenum nanowire catalyst in situ grown on nickel foam, which was recorded as sample 7.

[0112] Example 8 Sample morphology characterization

[0113] Typically, taking samples 1-3 as an example, scanning electron microscopy tests were performed on samples 1-3 to compare and analyze the morphological integrity of the catalyst nanowires at different activation times. Figure 3 a, b, and c are scanning electron micrographs of the catalysts of Examples 1 to 3 at 5000 times magnification. Figure 1) and the morphology of the catalyst ( Figure 2 As shown in Figure 2, it can be seen that compared with the catalyst precursor, the nanowires after constant current activation become rough, which increases the contact area with the substrate and is conducive to diffusion and mass transfer. Figure 3 It can be seen that the morphology of the catalyst nanowires after activation for 2h, 5h, and 30h is complete, proving that the prepared monolithic catalyst has excellent stability.

[0114] The catalyst prepared in Example 1 was tested and analyzed by transmission electron microscopy. The monolithic cobalt-doped nickel-molybdenum nanowire catalyst of Sample 1 was placed in an ethanol solution and ultrasonicated for 2 hours before the supernatant was dropped onto the microgrid. Figure 4 As shown in a, the diameter of the nanowires on the surface of the carrier in the selected area ranges from 50 to 100 nm, and the length ranges from 200 to 800 nm.

[0115] Example 9: Electrocatalytic Oxidation of 2,5-Furandimethanol (BHMF) to Prepare 2,5-Furandicarboxylic Acid (FDCA)

[0116] The electrocatalytic oxidation performance of the catalyst of Example 1 on BHMF was determined by linear sweep voltammetry. Figure 5 As shown, when the applied potential is only 1.32V, the current density can reach 10 mA per square centimeter. When the potential reaches 1.65V, the current density can reach 400 mA per square centimeter. The high current density can increase the reaction rate and greatly improve the conversion rate of 2,5-furan dimethanol.

[0117] Meanwhile, the monolithic catalyst obtained in Example 1 was used as the working electrode, along with a carbon rod as the counter electrode and mercury / mercuric oxide as the reference electrode, to form a three-electrode electrolysis system. 5 mL of 1 M KOH was used as the electrolyte. At a constant voltage of 1.474 V, 10 mM 2,5-furan dimethanol was electrocatalytically converted. Figure 6 This is a high-performance liquid chromatography analysis chart of each substance in the reaction process. Dual wavelengths (220nm, 265nm) were used to detect reactants, intermediates, and products. Under the condition of a wavelength of 220nm, the reactant BHMF peaked at 6.3min; under the condition of a wavelength of 265nm, the product FDCA peaked at 2.5min. As the electrolysis proceeded, the peak area of ​​the reactant BHMF gradually decreased, and the peak area of ​​the product FDCA gradually increased. According to the standard curve measured by the external standard method, the peak area was converted into the corresponding concentration of the substance and the conversion rate or yield of each substance in the reaction process was calculated, as shown below. Figure 7The conversion / yield plot over time shows that as the reaction proceeds, the amount of 2,5-furandimethanol (the raw material) decreases, while the yield of the main product, 2,5-furandicarboxylic acid, gradually increases. After a final reaction time of 0.91 h, the conversion of 2,5-furandimethanol reached 100%, the yield of the target product, 2,5-furandicarboxylic acid, was 98.18%, and the Faradaic efficiency was 97.9%. This demonstrates that the catalyst of this application achieves complete conversion of the reactants and a high yield of the target product. Furthermore, the Faradaic efficiency of the cathode hydrogen evolution reaction approaches 100%.

[0118] Example 10 Electrocatalytic Oxidation of 5-Hydroxymethylfurfural HMF to Prepare 2,5-Furandicarboxylic Acid FDCA

[0119] The monolithic catalyst obtained in Example 1 served as the working electrode, along with a carbon rod as the counter electrode and a mercury / mercuric oxide reference electrode, to form a three-electrode electrolysis system. 5 mL of 1M KOH was used as the electrolyte. Electrocatalytic conversion of 20 mM 5-HMF for 1 hour was achieved at a constant voltage of 1.6 V, resulting in a 99% conversion of 5-HMF and a 90% yield of 2,5-furandicarboxylic acid.

[0120] Example 11 Electrocatalytic Oxidation of 5-Hydroxymethyl-2-furancarboxylic Acid (HMFCA) to Prepare 2,5-Furandicarboxylic Acid (FDCA)

[0121] The monolithic catalyst obtained in Example 2 served as the working electrode, along with a carbon rod counter electrode and a mercury / mercuric oxide reference electrode, to form a three-electrode electrolysis system. 5 mL of 1 M KOH served as the electrolyte. Electrocatalytic conversion of 100 mM 5-hydroxymethyl-2-furancarboxylic acid was achieved at a constant voltage of 1.7 V for 3 hours, resulting in a final 5-hydroxymethyl-2-furancarboxylic acid conversion rate of 89% and a 2,5-furandicarboxylic acid yield of 82%.

[0122] Example 12 Electrocatalytic Oxidation of 2,5-Furandicarboxaldehyde DFF to Prepare 2,5-Furandicarboxylic Acid FDCA

[0123] The monolithic catalyst obtained in Example 3 served as the working electrode, along with a carbon rod counter electrode and a mercury / mercuric oxide reference electrode, to form a three-electrode electrolysis system. 5 mL of 1 M KOH served as the electrolyte. Electrocatalytic conversion of 100 mM 2,5-furandicarboxaldehyde was achieved at a constant voltage of 2 V for 2 hours, resulting in a final 2,5-furandicarboxaldehyde conversion rate of 86% and a 2,5-furandicarboxylic acid yield of 80%.

[0124] Example 13 Electrocatalytic Oxidation of 5-Formyl-2-Furancarboxylic Acid FFCA to Prepare 2,5-Furandicarboxylic Acid FDCA

[0125] The monolithic catalyst obtained in Example 3 served as the working electrode, along with a carbon rod as the counter electrode and a mercury / mercuric oxide reference electrode, to form a three-electrode electrolysis system. 5 mL of 1 M KOH served as the electrolyte. Electrocatalytic conversion of 200 mM 5-formyl-2-furancarboxylic acid was achieved at a constant voltage of 1.8 V for 1.5 hours, resulting in a final 5-formyl-2-furancarboxylic acid conversion rate of 89% and a 2,5-furandicarboxylic acid yield of 83%.

[0126] In summary, the cobalt-doped nickel-molybdenum nanowire electrocatalyst provided in this application has excellent stability and can meet the current density requirements required for industrial production. Furthermore, it can efficiently catalyze the conversion of 2,5-furan dimethanol, 5-hydroxymethylfurfural, 2,5-furandicarboxaldehyde, 5-hydroxymethyl-2-furancarboxylic acid, and 5-formyl-2-furancarboxylic acid to produce 2,5-furandicarboxylic acid, showing broad application prospects in the field of biomass electrocatalytic conversion.

[0127] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing a monolithic cobalt-doped nickel-molybdenum nanowire catalyst, characterized in that: The method comprises at least the following steps: Step 1: hydrothermally reacting a mixture containing a cobalt source, a nickel source, and a molybdenum source with a carrier to obtain a catalyst precursor; Step 2: electrochemically activating the catalyst precursor to obtain the monolithic cobalt-doped nickel-molybdenum nanowire catalyst; In an electrolytic cell containing an alkaline solution, the catalyst precursor is used as an anode to perform in-situ electrochemical activation to obtain the monolithic cobalt-doped nickel-molybdenum nanowire catalyst; The electrochemical activation conditions are: Select activation current density between 1 and 100 mA / cm 2 , activation time is 1~20 h; The catalyst comprises a carrier and an active substance grown in situ on the carrier; the nanowires of the catalyst obtained in step 2) have a diameter of 50 to 100 nm and a length of 200 to 800 nm; The active material includes cobalt, nickel and molybdenum.

2. The preparation method according to claim 1, characterized in that In the catalyst, the content of cobalt element is 1-10 wt%, the content of nickel element is 50-80 wt%, and the content of molybdenum element is 10-30 wt%. The content of each element is expressed in percentage by mass.

3. The preparation method according to claim 1, characterized in that The carrier is selected from any one of foam metal, carbon fiber cloth, and sheet metal.

4. The preparation method according to claim 3, characterized in that The active substance is in the form of nanowires on the carrier.

5. The preparation method according to claim 1, characterized in that In step 1, the cobalt source is selected from at least one of cobalt nitrate hexahydrate, cobalt sulfate, cobalt chloride hexahydrate, and cobalt acetate tetrahydrate; The nickel source is selected from at least one of nickel nitrate hexahydrate, nickel acetate tetrahydrate, nickel chloride hexahydrate, and nickel sulfate hexahydrate; The molybdenum source is selected from at least one of sodium molybdate dihydrate and ammonium molybdate tetrahydrate.

6. The preparation method according to claim 1, characterized in that Based on the molar number of each substance itself, in step 1, the molar ratio of the cobalt source to the nickel source in the mixture is 1:5~1:100, and the molar ratio of the molybdenum source to the nickel source is 1:5~1:

50.

7. The preparation method according to claim 1, characterized in that In step 1, the mixture further comprises a solvent; In the mixture, the molar ratio of the cobalt source to the solvent is 1:2000 to 1:12000, calculated on the molar basis of the substance itself; The solvent includes water.

8. The preparation method according to claim 1, characterized in that In step 1, the conditions of the hydrothermal reaction are: The reaction temperature is 110 ℃~200 ℃, and the reaction time is 2 h~15 h.

9. The preparation method according to claim 1, characterized in that The alkaline solution is selected from at least one of sodium hydroxide and potassium hydroxide solution; In the alkaline solution, the concentration of hydroxide is 0.1 mol / L~3 mol / L.

10. A method for preparing 2,5-furandicarboxylic acid, characterized in that: The method at least comprises: The solution containing the reaction substrate is reacted under the action of a catalyst to obtain 2,5-furandicarboxylic acid; The reaction substrate is selected from at least one of 2,5-furan dimethanol, 5-hydroxymethylfurfural, 2,5-furandicarboxaldehyde, 5-hydroxymethyl-2-furancarboxylic acid, and 5-formyl-2-furancarboxylic acid; The catalyst is selected from at least one of the monolithic cobalt-doped nickel-molybdenum nanowire catalysts prepared by the method according to any one of claims 1 to 9.

11. The method for preparing 2,5-furandicarboxylic acid according to claim 10, characterized in that: The method comprises: The reaction substrate is used as a raw material and the catalyst is used as a working electrode to carry out an electrochemical reaction to obtain the 2,5-furandicarboxylic acid.

12. The method for preparing 2,5-furandicarboxylic acid according to claim 11, characterized in that: The electrochemical reaction conditions are: The reaction voltage is 1.1~3 V, and the reaction time is 0.5~5 h.

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