A method for preparing a refractory metal-doped cobalt-based catalyst

Abstract

The present invention discloses a method for preparing a refractory metal-doped cobalt-based catalyst, comprising the following steps: S1. Preparation of a cobalt-based precursor; S2. Carboxylation of a metal; S3. Preparation of a cobalt-refractory metal-based precursor; S4. Preparation of a refractory metal-doped cobalt-based catalyst; The present invention successfully introduces a refractory metal into an electrocatalyst, suppresses the dissolution of cobalt ions, and can effectively reduce the secondary pollution caused by the dissolution of the cobalt element. The prepared catalyst is soaked in a 1M nitric acid solution at 80°C for 24h and then continues to be soaked at room temperature for more than three months. The soaking liquid is still clear and transparent (if the cobalt ions are dissolved, the solution generally presents pink), thereby successfully reducing the toxicity of the catalyst. Such catalysts also have good active persulfate performance, and the mass loss of polyvinyl chloride reaches ~20% after being treated at 120°C and 8h.

Description

Technical Field

[0001] The invention relates to the technical field of cobalt-based catalyst preparation, and in particular to a method for preparing a refractory metal-doped cobalt-based catalyst. Background Art

[0002] Microplastics are plastic particles with an effective diameter of less than 5mm. They can be divided into primary microplastics and secondary microplastics. Primary microplastics are microplastics that are produced for the first time. Secondary microplastics refer to plastic fragments produced after the decomposition of large plastics. Microplastics are now widely present in marine and terrestrial ecosystems. As an organic pollutant, the harm of microplastics has been growing. The degradation methods of microplastics can be divided into physical treatment, chemical treatment and biological treatment.

[0003] Advanced oxidation method is an emerging wastewater treatment technology in the field of water treatment in recent years. Compared with traditional wastewater treatment technology, it can efficiently treat microplastics in wastewater and reduce microplastic pollution in the water environment caused by wastewater discharge. The principle is that the oxidant decomposes under the action of light, sound, electricity, high temperature and high pressure, and catalysts to produce active free radicals with strong oxidizing ability. The free radicals combine with organic compounds to undergo substitution, addition, bond breaking and other reactions, and directly mineralize toxic and difficult-to-degrade macromolecular organic pollutants into small molecular substances, such as carbon dioxide and water. There are many types of advanced oxidation methods. The most commonly used ones are the Fenton advanced oxidation method based on hydroxyl free radicals and the persulfate advanced oxidation method based on sulfate free radicals. French scientist Henry Fenton discovered that when the pH is acidic, hydrogen peroxide (H2O2) reacts with ferrous ions (Fe 2+ ) as a catalyst can oxidize and degrade tartaric acid. 2+ The / H2O2 reagent is named Fenton's reagent, and the reaction of oxidizing organic matter with this reagent is called Fenton's reaction.

[0004] The persulfate oxidation method is a Fenton-like reaction. Persulfate contains highly oxidizing peroxide groups. Its cleavage can produce sulfate radicals (·SO4 -). The oxidation principle of sulfate radicals is similar to that of hydroxyl radicals, but they are more stable than hydroxyl radicals, and under neutral conditions, sulfate radicals have a higher standard reduction potential. However, persulfate is relatively stable at room temperature, and it is necessary to activate persulfate by heat, light, ultrasound, transition metals, carbon-based materials and other methods to achieve the purpose of degrading microplastics. Transition metal ion activation of persulfate is the most common way to activate persulfate. It can decompose persulfate at room temperature to produce sulfate radicals. Cobalt ion is the transition metal ion with the best performance in activating persulfate so far (Environmental Science & Technology, 2004, 38, 13, 3705), but the widespread toxicity of transition metal ions affects their practical application. Therefore, it is an urgent problem to provide a method for preparing a cobalt-based catalyst to solve the defects of the above-mentioned transition metal ions. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a refractory metal-doped cobalt-based catalyst. The present invention successfully introduces refractory metals into the electrocatalyst, inhibits the dissolution of cobalt ions, and can effectively reduce the secondary pollution caused by the dissolution of cobalt elements. The prepared catalyst is soaked in 1M nitric acid solution at 80°C for 24 hours and then soaked at room temperature for more than three months. The soaking liquid is still clear and transparent (if cobalt ions are dissolved, the solution generally appears pink), thereby successfully reducing the toxicity of the catalyst. This type of catalyst also has good active persulfate performance. The mass loss of polyvinyl chloride after being treated at 120°C for 8 hours reaches 20%.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a refractory metal-doped cobalt-based catalyst comprises the following steps:

[0008] S1. Preparation of a cobalt-based precursor: growing a basic cobalt salt on the surface of a substrate in a water bath, and then coating the surface of the basic cobalt salt with dopamine to obtain a cobalt-based precursor, wherein the reaction temperature of the water bath is 80-100° C. and the reaction time is 1-3 h;

[0009] S2. Carboxylation of metals: prepare a mixed salt solution of cobalt and refractory metals, add a carboxylic acid precursor, and stir for 2-3 hours to obtain a metal carboxylic acid complex;

[0010] S3. Preparation of a cobalt-refractory metal-based precursor: mixing the metal carboxylic acid complex obtained in step S2 with the cobalt-based precursor obtained in step S1 and reacting them to obtain a cobalt-refractory metal-based precursor;

[0011] S4. Preparation of refractory metal-doped cobalt-based catalyst: annealing the cobalt-refractory metal-based precursor prepared in step S3 under an inert atmosphere, and taking it out after cooling in the furnace to obtain a refractory metal-doped cobalt-based catalyst.

[0012] Preferably, in step S1, the substrate is carbon cloth.

[0013] Preferably, in step S1, the concentration of dopamine coating the cobalt-based precursor is 0.4-0.8 mg / mL.

[0014] Preferably, in step S1, the preparation method of the basic cobalt salt is: dissolving cobalt chloride and urea in 30-50 mL of deionized water at a mass ratio of 1:1.5-3 to obtain the basic cobalt salt.

[0015] Preferably, the refractory metal is selected from one or more of Mo, V, or Cr.

[0016] Preferably, in step S2, the mass ratio of the carboxylic acid precursor to the mixed salt solution of cobalt and refractory metal is 3-4:1; and the carboxylic acid precursor is selected from one or more of acetic anhydride and benzoic anhydride.

[0017] Preferably, in step S2, the atomic ratio of cobalt to refractory metal in the cobalt-refractory metal-based precursor is 0.5 to 3:1.

[0018] Preferably, in step S3, the reaction is a water bath reaction; the working parameters of the reaction are limited to: reaction temperature 80-100° C., reaction time 1-3 h.

[0019] Preferably, in step S3, the reaction is a hydrothermal reaction; the working parameters of the reaction are limited to: reaction temperature 110-130° C., reaction time 1-3 h.

[0020] Preferably, in step S4, the reaction parameters of the annealing are defined as follows: the reaction temperature is 600-900° C., and the reaction time is 1-3 h.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. Successfully introduced refractory metals into the electrocatalyst, inhibiting the dissolution of cobalt ions and effectively reducing the secondary pollution caused by the dissolution of cobalt elements;

[0023] 2. The present invention has the advantages of low equipment requirements, low cost, easy control of reaction conditions, simple production process, and little environmental pollution;

[0024] 3. The catalyst prepared by the present invention can efficiently activate persulfate and successfully inhibit the dissolution of cobalt, which has great environmental significance for the degradation of microplastics. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a flow chart of the preparation process of the refractory metal-doped cobalt-based catalyst;

[0026] Figure 2 The variable speed cyclic voltammetry curves of the sample prepared in Example 1 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 1, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0027] Figure 3 The variable speed cyclic voltammetry curves of the sample prepared in Example 2 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 2, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0028] Figure 4 The variable speed cyclic voltammetry curves of the sample prepared in Example 3 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 3, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0029] Figure 5 The variable speed cyclic voltammetry curves of the sample prepared in Example 41 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 4, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0030] Figure 6 The variable speed cyclic voltammetry curves of the sample prepared in Example 5 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 5, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0031] Figure 7 The variable speed cyclic voltammetry curves of the sample prepared in Example 6 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 6, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0032] Figure 8 The variable speed cyclic voltammetry curves of the sample prepared in Example 7 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 7, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0033] Fig. 9 The variable speed cyclic voltammetry curves of the sample prepared in Example 8 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 8, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0034] Fig.10 The variable speed cyclic voltammetry curves of the sample prepared in Example 9 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 9, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0035] Fig.11 The variable speed cyclic voltammetry curves of the sample prepared in Example 10 of the present invention are as follows: (a) is the variable speed cyclic voltammetry curve (CV) of the sample prepared in Example 10, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1V, and the slope of the straight line is the double layer capacitance (C dl );

[0036] Fig.12 The XRD graphs of the refractory metal-doped cobalt-based catalysts of the present invention are as follows: from top to bottom, they are the XRD curves of the samples prepared in Example 5, Example 4, Example 1 and Example 3;

[0037] Fig.13 The XRD graphs of the refractory metal-doped cobalt-based catalysts of the present invention are as follows: from top to bottom, they are the XRD curves of the samples prepared in Example 7 and Example 8;

[0038] Fig.14 The SEM images of the refractory metal-doped cobalt-based catalyst of the present invention are as follows: (a) is a SEM image of the sample prepared in Example 1 magnified 10,000 times; (b) is a SEM image of the sample prepared in Example 1 magnified 40,000 times; (c) is a SEM image of the sample prepared in Example 3 magnified 10,000 times; (d) is a SEM image of the sample prepared in Example 3 magnified 40,000 times;

[0039] Fig.15 The SEM images of the refractory metal-doped cobalt-based catalyst of the present invention are as follows: (a) is a SEM image of the sample prepared in Example 4 magnified 10,000 times; (b) is a SEM image of the sample prepared in Example 4 magnified 40,000 times; (c) is a SEM image of the sample prepared in Example 5 magnified 10,000 times; (d) is an SEM image of the sample prepared in Example 5 magnified 20,000 times;

[0040] Fig.16 The SEM images of the refractory metal-doped cobalt-based catalyst of the present invention are as follows: (a) is a SEM image of the sample prepared in Example 7 magnified 10,000 times; (b) is a SEM image of the sample prepared in Example 7 magnified 40,000 times; (c) is a SEM image of the sample prepared in Example 8 magnified 10,000 times; (d) is a SEM image of the sample prepared in Example 8 magnified 40,000 times:

[0041] Fig.17 This is a microplastic degradation time diagram of a sample prepared in Example 1 of the present invention;

[0042] Fig.18 This is a comparison chart of microplastic degradation performance of samples prepared in Example 1 and Example 3 of the present invention;

[0043] Fig.19 This is a comparison chart of microplastic degradation performance of samples prepared in Example 7 and Example 8 of the present invention;

[0044] Fig. 20 This is a comparison chart of microplastic degradation performance of samples prepared in Comparative Examples 1 and 2 of the present invention;

[0045] Fig.21 It is a comparison chart of the degradation performance of Example 1, Example 3, Example 4, Example 5, Example 7, Example 8, Example 9, Example 10 of the present invention, Control Sample 1 and Control Sample 2 under the same degradation time. DETAILED DESCRIPTION

[0046] The present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] See also Figure 1-21 , the present invention provides a technical solution:

[0048] Embodiment 1:

[0049] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0050] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.04g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.39g of ammonium molybdate, dissolve them in 60ml of deionized water, add 3.15g of acetic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-molybdenum precursor with a cobalt-molybdenum atomic ratio of 1:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0051] Embodiment 2:

[0052] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0053] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.04g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.20g of ammonium molybdate, dissolve them in 60ml of deionized water, add 3.15g of acetic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-molybdenum precursor with a cobalt-molybdenum atomic ratio of 2:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0054] Embodiment 3:

[0055] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.04g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.13g of ammonium molybdate, dissolve them in 60ml of deionized water, add 3.15g of benzoic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-molybdenum precursor with a cobalt-molybdenum atomic ratio of 3:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 800℃ at a rate of 5℃ / min, and keep it warm for 2h. Take it out after cooling to room temperature.

[0056] Embodiment 4:

[0057] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0058] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.39g of ammonium molybdate, dissolve them in 60ml of deionized water, add 3.15g of benzoic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-molybdenum precursor with a cobalt-molybdenum atomic ratio of 1:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 600℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0059] Embodiment 5:

[0060] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0061] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.39g of ammonium molybdate, dissolve them in 60ml of deionized water, add 3.15g of acetic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-molybdenum precursor with a cobalt-molybdenum atomic ratio of 1:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 600℃ at a rate of 5℃ / min, and keep it warm for 3h. Take it out after cooling to room temperature.

[0062] Embodiment 6:

[0063] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0064] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.13g of ammonium metavanadate, dissolve them in 60ml of deionized water, add 3.15g of acetic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-vanadium precursor with a cobalt-vanadium atomic ratio of 2:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0065] Embodiment 7:

[0066] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0067] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.09g of ammonium metavanadate, dissolve them in 60ml of deionized water, add 3.15g of benzoic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-vanadium precursor with a cobalt-vanadium atomic ratio of 3:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0068] Embodiment 8:

[0069] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0070] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.09g of ammonium metavanadate, dissolve them in 60ml of deionized water, add 3.15g of benzoic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and hydrothermal at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-vanadium precursor with a cobalt-vanadium atomic ratio of 3:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 800℃ at a rate of 5℃ / min, and keep it warm for 2h. Take it out after cooling to room temperature.

[0071] Embodiment 9:

[0072] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0073] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.17g of chromium acetate, dissolve them in 60ml of deionized water, add 3.15g of benzoic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and place in a water bath at 90℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-chromium precursor with a cobalt-chromium atomic ratio of 3:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0074] Embodiment 10:

[0075] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0076] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride and 0.17g of chromium acetate, dissolve them in 60ml of deionized water, add 3.15g of acetic anhydride, stir for 2h, then add a piece of cobalt-based precursor coated with dopamine, and place in a water bath at 90℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-chromium precursor with a cobalt-chromium atomic ratio of 3:1. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, and then heat it from 350℃ to 800℃ at a rate of 5℃ / min, and keep it warm for 2h. Take it out after cooling to room temperature.

[0077] Comparative Example

[0078] Comparative Example 1:

[0079] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0080] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride, dissolve it in 60ml of deionized water, then add a piece of cobalt-based precursor coated with dopamine, and hydroheat it at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-based precursor without doping refractory metals. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 700℃ at a rate of 5℃ / min, and keep it warm for 1h. Take it out after cooling to room temperature.

[0081] Comparative Example 2:

[0082] A method for preparing a refractory metal-doped cobalt-based catalyst:

[0083] Take 1.43g of cobalt chloride and 2.67g of urea and dissolve them in 40ml of deionized water. Place the hydrophilic treated carbon cloth (2.5cm×5cm) in the above solution and keep it heated in a 90℃ water bath for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.61g of tris(hydroxymethyl)aminomethane and dissolve it in 500ml of deionized water to prepare a Tris solution, and adjust its pH value to 8.5. Weigh 0.08g of dopamine hydrochloride and add it to a beaker. Take the carbon cloth grown with a cobalt-based precursor, hang it on a beaker, and completely immerse it in the solution. Place the beaker on a stirring table, add a magnet, keep the solution in a low-speed stirring state for 24h, then take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃. Take 0.54g of cobalt chloride, dissolve it in 60ml of deionized water, then add a piece of cobalt-based precursor coated with dopamine, and hydroheat it at 120℃ for 2h. After cooling to room temperature, take it out, rinse the surface of the carbon cloth with deionized water, place it on a clean filter paper, and dry it on a hot plate at 80℃ to obtain a cobalt-based precursor without doping refractory metals. Place it on a corundum boat, then transfer it to a quartz tube, place it on a tube furnace, and anneal it in an argon atmosphere. First, heat it from room temperature to 350℃ at a rate of 5℃ / min, keep it warm for 2h, then heat it from 350℃ to 800℃ at a rate of 5℃ / min, and keep it warm for 2h. Take it out after cooling to room temperature.

[0084] Data Characterization:

[0085] 1. Characterization and test conditions

[0086] Material characterization: XRD diffraction was performed using a Rigaku Ultima IV X-ray diffractometer to characterize the samples; a FESEM field emission scanning electron microscope was used to characterize the surface morphology and microstructure of the above samples.

[0087] Cyclic voltammetry (CV) test: The electrochemical test was performed using the Shanghai Chenhua CHI760E electrochemical workstation, and a three-electrode system was used in a 1M KOH electrolyte. The catalyst prepared above was cut into small pieces of 0.5 cm × 2 cm and clamped on the working electrode, a carbon rod was used as the counter electrode, and a saturated Hg / HgO electrode was used as the reference electrode. All working potentials used were calibrated with a reversible hydrogen electrode (RHE). Before the CV curve test, oxygen was introduced into the electrolyte for 0.5 h to saturate it with oxygen. The non-Faraday interval double-layer capacitance current corresponding to the variable-speed cyclic voltammetry curve with a scan rate of 20 mV s-1 to 100 mV s-1 was plotted using the current density and scan rate at a certain potential, and a straight line was obtained through linear fitting. The slope of the straight line is the double-layer capacitance C dl According to the formula ECSA=C dl / Cs, and calculate the electrochemical active area (ECSA) of the catalyst. Where Cs is the surface double layer capacitance of an ideal smooth oxide, which is taken as 20μF / cm 2 .

[0088] Microplastic degradation experiment: In this paper, the prepared catalyst was added to deionized water containing persulfate, and then polyvinyl chloride was added to degrade microplastics through hydrothermal reaction. The mass change of polyvinyl chloride before and after was calculated to obtain the performance of the catalyst in degrading microplastics.

[0089] 2. Data Analysis

[0090] Figure 2 In the figure, (a) is the CV curve of the sample prepared in Example 1, and (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V. The slope of the straight line is the double layer capacitance (C dl ). According to the double-layer capacitance, the electrochemical active area of ​​Co-Mo(1:1)-700-1 can be calculated to be 932.

[0091] Figure 3 In the figure, (a) is the CV curve of the sample prepared in Example 2, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double layer capacitance, the electrochemical active area of ​​Co-Mo(2:1)-700-1 can be calculated to be 317.5.

[0092] Figure 4 In the figure, (a) is the CV curve of the sample prepared in Example 3, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double-layer capacitance, the electrochemical active area of ​​Co-Mo(3:1)-800-2 can be calculated to be 106.

[0093] Figure 5 In the figure, (a) is the CV curve of the sample prepared in Example 4, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double-layer capacitance, the electrochemical active area of ​​Co-Mo(1:1)-600-1 can be calculated to be 300.

[0094] Figure 6 In the figure, (a) is the CV curve of the sample prepared in Example 5, and (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V. The slope of the straight line is the double layer capacitance (C dl). According to the double layer capacitance, the electrochemical active area of ​​Co-Mo(1:1)-600-3 can be calculated to be 25.

[0095] Figure 7 In the figure, (a) is the CV curve of the sample prepared in Example 6, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double layer capacitance, the electrochemical active area of ​​Co-V(2:1)-700-1 can be calculated to be 434.

[0096] Figure 8 In the figure, (a) is the CV curve of the sample prepared in Example 7, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double-layer capacitance, the electrochemical active area of ​​Co-V(3:1)-700-1 can be calculated to be 389.5.

[0097] Fig. 9 In the figure, (a) is the CV curve of the sample prepared in Example 8, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double-layer capacitance, the electrochemical active area of ​​Co-V(3:1)-800-2 can be calculated to be 510.5.

[0098] Fig.10 In the figure, (a) is the CV curve of the sample prepared in Example 9, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double layer capacitance, the electrochemical active area of ​​Co-Cr(3:1)-700-1 can be calculated to be 516.

[0099] Fig.11 In the figure, (a) is the CV curve of the sample prepared in Example 10, (b) is the linear fitting diagram of the current density difference and the scan rate corresponding to the potential of 1 V, and the slope of the straight line is the double layer capacitance (C dl ). According to the double layer capacitance, the electrochemical active area of ​​Co-Cr(3:1)-800-2 can be calculated to be 202.5.

[0100] Fig.12 XRD patterns of samples and PDF#34-0511 standard cards prepared for Example 1, Example 3, Example 4 and Example 5. As can be seen from the figure, the pattern corresponds to the diffraction peak of Co2Mo3O8.

[0101] Fig.13 XRD patterns of samples and PDF32-1413 standard cards prepared in Example 7 and Example 8. As can be seen from the figure, the diffraction peaks corresponding to V2N in the spectrum

[0102] Fig.14 The SEM images of the samples prepared in Example 1 and Example 3 are shown. It can be seen from the figure that when the ratio of cobalt to molybdenum is 1:1, hexagonal flakes with a diameter of about 0.5 to 1 μm grow on the carbon fiber substrate. When the ratio of cobalt to molybdenum is 3:1, after the annealing temperature is increased, the structure grown on the surface is irregular and the crystal structure is also smaller overall.

[0103] Fig.15 The SEM images of the samples prepared in Example 5 and Example 6. As can be seen from the figure, when the annealing temperature is 600°C, a granular morphology grows on the carbon fiber.

[0104] Fig.16 The SEM images of the samples prepared in Example 7 and Example 8 are shown. As can be seen from the figure, there are many agglomerates of irregular shapes and sizes on the carbon fiber as a whole. When a part is selected and enlarged, some small particles with a diameter of about 50 to 100 nm can be observed stacked together to form this type of morphology. In (c) to (d), a relatively regular and dense morphology can be observed, but there are still some small clusters attached to the surface of the carbon fiber. In the enlarged image, it is observed that the surface of the carbon fiber shows a granular morphology with a diameter of about 150 nm, which is regularly distributed on the carbon fiber.

[0105] Fig.17 The relationship between the degradation performance of microplastics and time of the sample prepared in Example 1 is shown in the figure. As can be seen from the figure, with the extension of degradation time, the mass loss of microplastics continues to increase. When the degradation time reaches 4h, the mass loss of microplastics is 13.6%. When the degradation time is extended to 36h, the mass loss of microplastics reaches 25.1%. Although the mass loss continues to increase, the increase rate continues to decrease. In the 24h and 36h comparative experiments, the mass loss of microplastics is less than 1%. It can be inferred that as the degradation time continues to extend, the mass loss of microplastics will no longer increase significantly, and after 36h of degradation, the mass loss almost reaches the peak.

[0106] Fig.18 This is a comparison chart of the microplastic degradation performance of the samples prepared in Example 1 and Example 3.

[0107] Fig.19 This is a comparison chart of the microplastic degradation performance of the samples prepared in Example 7 and Example 8.

[0108] Fig. 20 The microplastic degradation performance comparison chart of the samples prepared for control sample 1 and control sample 2.

[0109] Fig.21 The comparison chart of microplastic degradation performance of samples prepared for Example 1, Example 3, Example 4, Example 5, Example 7, Example 8, Control Sample 1 and Control Sample 2 at the same degradation time is as follows:

[0110] In the experimental group where only persulfate was added, the mass loss of microplastics reached 3%. In the experimental group where the sample Co-Mo (1: 1) -700-1 prepared in Example 1 and persulfate were added, the mass loss of microplastics reached 21.7%. In the experimental group where the sample Co-Mo (1: 1) -600-1 prepared in Example 4 and persulfate were added, the mass loss of microplastics reached 12.9%. In the experimental group where the sample Co-Mo (1: 1) -600-3 prepared in Example 5 and persulfate were added, the mass loss of microplastics reached 10.1%. In the experimental group where the sample Co-V (3: 1) -700-1 prepared in Example 7 and persulfate were added, the mass loss of microplastics reached 12.6%. In the experimental group where the sample Co-Mo (1: 1) -800-2 prepared in Example 8 and persulfate were added, the mass loss of microplastics reached 10%. In the experimental groups of control sample 1 and control sample 2 without refractory metal doping, the mass loss of microplastics was 14.9% and 12.3%, respectively.

[0111] The present invention performs structural characterization and performance testing on Examples 1-10 and Comparative Examples 1-2. Through SEM scanning of Examples 1, 3, 4, 5, 7, and 8, it can be seen that there are more granular morphologies on the carbon cloth, and the XRD graphs of Examples 1, 3, 4, and 5 correspond to the diffraction peaks of Co2Mo3O8, and the XRD graphs of Examples 7 and 8 have the diffraction peaks of V2N, which indicates that the present invention successfully introduces refractory metals into the surface of carbon cloth and combines with it, and prepares a new refractory metal-doped cobalt-based catalyst; Fig.21 Further, a comparison chart of the degradation performance of Examples 1, 3, 4, 5, 7, 8, 9, 10 of the present invention and Comparative Examples 1 and 2 is shown. The data in the chart strongly proves that the refractory metal-doped cobalt-based catalyst prepared by the method provided by the present invention has excellent microplastic degradation performance and has obvious application value in the field of microplastic degradation.

[0112] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a refractory metal-doped cobalt-based catalyst, characterized in that: The following steps are involved: S1. Preparation of a cobalt-based precursor: growing a basic cobalt salt on the surface of a substrate in a water bath, and then coating the surface of the basic cobalt salt with dopamine to obtain a cobalt-based precursor, wherein the reaction temperature of the water bath is 80-100° C. and the reaction time is 1-3 h; S2. Carboxylation of metals: prepare a mixed salt solution of cobalt and refractory metals, add a carboxylic acid precursor, and stir for 2-3 hours to obtain a metal carboxylic acid complex; S3. Preparation of a cobalt-refractory metal-based precursor: mixing the metal carboxylic acid complex obtained in step S2 with the cobalt-based precursor obtained in step S1 and reacting them to obtain a cobalt-refractory metal-based precursor; S4. Preparation of a refractory metal-doped cobalt-based catalyst: annealing the cobalt-refractory metal-based precursor prepared in step S3 under an inert atmosphere, cooling the precursor and removing the precursor from the furnace to obtain a refractory metal-doped cobalt-based catalyst; In step S2, the mass ratio of the carboxylic acid precursor to the mixed salt solution of cobalt and refractory metal is 3-4:1; the carboxylic acid precursor is selected from one or more of acetic anhydride and benzoic anhydride, the refractory metal is Mo, and the atomic ratio of cobalt to refractory metal Mo in the cobalt-refractory metal-based precursor is 1:1; In step S4, the reaction parameters of the annealing are defined as firstly heating from room temperature to 350°C at a rate of 5°C / min, keeping the temperature for 2 hours, then heating from 350°C to 700°C at a rate of 5°C / min, keeping the temperature for 1 hour, and then taking out after cooling to room temperature.

2. The method for preparing a refractory metal-doped cobalt-based catalyst according to claim 1, characterized in that: In step S1, the substrate is carbon cloth.

3. The method for preparing a refractory metal-doped cobalt-based catalyst according to claim 1, characterized in that: In step S1, the concentration of dopamine coated on the cobalt-based precursor is 0.4-0.8 mg / mL.

4. The method for preparing a refractory metal-doped cobalt-based catalyst according to claim 1, characterized in that: In step S1, the preparation method of the basic cobalt salt is: dissolving cobalt chloride and urea in 30-50 mL of deionized water at a mass ratio of 1:1.5-3 to obtain the basic cobalt salt.

5. The method for preparing a refractory metal-doped cobalt-based catalyst according to claim 1, characterized in that: In step S3, the reaction is a water bath reaction; the working parameters of the reaction are limited to: reaction temperature 80-100° C., reaction time 1-3 h.

6. The method for preparing a refractory metal-doped cobalt-based catalyst according to claim 1, characterized in that: In step S3, the reaction is a hydrothermal reaction; the working parameters of the reaction are limited to: reaction temperature 110-130° C., reaction time 1-3 h.

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