Method for controllably growing Ni0.85Se on surface of carbon nanofiber and application of method
By controlling the growth of Ni0.85Se on the surface of carbon nanofibers, the challenge of uniform coating and component regulation of nickel-based catalysts on the base material is solved, and efficient urea oxidation catalytic performance and stability are achieved.
Patent Information
- Application Number
- CN202411689338.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-25
AI Technical Summary
There are challenges in uniform coating and component regulation of existing nickel-based catalysts on the base material, and the shedding of active components during the catalysis process will lead to a degradation of catalytic performance.
The method of controlling the growth of Ni0.85Se on the surface of carbon nanofibers is adopted to regulate the surface state and porosity of fibers by introducing high-temperature and easy-to-depolymerize polymethyl methacrylate, promote the nucleation and growth of Ni0.85Se, and control the active phase components through hydrothermal selenization reaction.
The uniform coating of the Ni0.85Se nanoparticle shell on the surface of the carbon nanofiber was achieved, which improved the stability and activity of the catalyst, was able to achieve high current density at lower potentials, and showed long-term catalytic performance in the stability test.
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Abstract
Description
Technical Field
[0001] The present invention relates to the field of electrocatalyst design, and in particular to a method for controlling the growth of Ni on the surface of carbon nanofibers. 0.85 Se method and its application in the field of urea oxidation assisted water electrolysis to produce hydrogen. Background Art
[0002] Hydrogen (H2) is an ideal energy carrier that can be used to overcome the energy crisis and environmental pollution caused by fossil fuel consumption. At present, sustainable energy-driven hydrogen power generation through water splitting reaction has attracted great attention. The high energy barrier of the anodic oxygen evolution reaction (OER) in the overall water splitting greatly reduces the energy conversion efficiency. Therefore, it is urgent to develop efficient electrocatalysts and alternative anodic oxidation reactions to reduce the driving voltage. In recent years, urea oxidation reaction (UOR) has attracted widespread attention due to its ability to simultaneously produce H2 and alleviate urea-rich wastewater. UOR has a lower thermodynamic equilibrium potential (0.37V) and is considered to be a promising alternative to OER. UOR is a complex process that requires high-performance catalysts to complete the 6 electron transfer steps. Studies have found that nickel-based catalysts can provide high-valent nickel species active phases for UOR through electrochemical and chemical oxidation mechanisms. In order to improve the catalytic activity and stability, nickel-based compounds are usually loaded on conductive substrates. However, the uniform coating and component regulation of nickel-based compounds on substrates still face certain challenges, and the shedding of active components during the catalytic process will cause the catalytic performance to decline. Therefore, developing a simple and controllable method for constructing nickel-based active components is of great research significance. Summary of the invention
[0003] 1. A controllable growth of Ni on the surface of carbon nanofibers 0.85 Se method. The preparation process is as follows:
[0004] (1) Prepare a precursor solution by mixing 400 mg of polyacrylonitrile and 100 mg of polymethyl methacrylate at 60 °C.
[0005] ℃, dissolved in N,N-dimethylformamide, cooled to room temperature, added 250 mg of nickel acetate tetrahydrate and stirred continuously until a uniform spinning solution was formed; then, electrospinning was carried out at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber membrane was collected on an aluminum foil about 20 cm away from the tip of the syringe.
[0006] (2) The nanofiber membrane was placed in a quartz crucible and pre-oxidized at 250 °C in air for 2 h in a tube furnace, and then carbonized at 800 °C in an Ar atmosphere for 2 h to obtain porous nickel / carbon nanofibers (Ni-PCNFs).
[0007] (3) 34.4 mg of anhydrous sodium selenite was dissolved in 15 mL of water, and 183 μL of hydrazine hydrate was added to prepare a uniform solution A, which was vigorously stirred for 20 min. Subsequently, 5 mg of Ni-PCNFs was ultrasonically dispersed in 10 mL of water, and different molar amounts of nickel acetate were added after dispersion to obtain dispersion B. Subsequently, A and B were mixed and vigorously stirred for 20 min and then transferred to a reactor for selenization reaction at 180 ° C for 8 h. The product was washed with water and ethanol several times and then dried in an oven at 50 ° C to obtain Ni-PCNFs@NiSe composite nanofibers.
[0008] 2. The carbon nanofiber surface controllable growth Ni according to claim 1 0.85 Se method, the mass fraction of polymethyl methacrylate in step (1) is controlled to be 0, 0.1, 0.2, 0.3 (mass of polymethyl methacrylate: total mass of polymer).
[0009] 3. The carbon nanofiber surface controllable growth Ni according to claim 1 0.85 Se method, the molar concentration of nickel acetate in the hydrothermal system in step (3) is 1, 2, 3, 4 mM.
[0010] The advantages of the present invention are as follows:
[0011] The present invention adopts a simple and controllable method to uniformly coat Ni on the surface of carbon nanofibers. 0.85 Se nanoparticle shell. The prepared porous composite nanofibers can reach 20 mA cm at a potential of 1.37 V vs. RHE. -2 The current density reaches 275 mA cm -2 The current density only requires 1.55 V vs. RHE, and at 15 mA cm -2 The reaction can be stable for 48 h at a current density of 1.5 wt %.
[0012] The innovative features of the method of the present invention compared with the prior art are:
[0013] (1) In the present invention, polymethyl methacrylate, which is easily depolymerized at high temperature, is introduced to regulate the surface state and porosity of carbon nanofibers, thereby promoting Ni 0.85 Nucleation and growth of Se on the fiber surface;
[0014] (2) The introduction of Ni species into the fiber can not only promote the 0.85 Se nucleates and grows on the fiber surface, which can also enhance the Ni 0.85 The binding force between Se and carbon nanofiber substrate inhibits its agglomeration and shedding during the catalytic process.
[0015] (3) The present invention can achieve the regulation of the active phase components growing on the fiber surface by simply adjusting the amount of Ni salt added during the hydrothermal process. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 : Ni-PCNFs prepared in Examples 2, 3 and 4 of the present invention 0.2 @NiSe-2, Ni-CNFs@NiSe-2, Ni-PCNFs 0.1 @NiSe-2 and Ni-PCNFs not described in detail 0.3 @SEM image of NiSe-2.
[0017] Figure 2 : Ni-PCNFs prepared in Examples 1 and 2 of the present invention 0.2 @NiSe-1、Ni-PCNFs 0.2 @NiSe-2 and Ni-PCNFs not described in detail 0.2 @NiSe-3、Ni-PCNFs 0.2 @SEM image of NiSe-4.
[0018] Figure 3 : Ni-PCNFs prepared in Examples 1 and 2 of the present invention 0.2 @NiSe-1、Ni-PCNFs 0.2 @NiSe-2 and Ni-PCNFs not described in detail 0.2 @NiSe-3、Ni-PCNFs 0.2 @XRD spectrum of NiSe-4.
[0019] Figure 4 : LSV curve of Example 1 of the present invention under alkaline conditions.
[0020] Figure 5 : it curve of Example 1 of the present invention under alkaline conditions.
[0021] Figure 6 : The full hydrolysis LSV curve of Example 2 of the present invention under alkaline conditions. Specific implementation methods
[0023] In order to more clearly illustrate the present invention, the following embodiments are listed, but they do not limit the scope of the present invention in any way. The technical solutions in the embodiments of the present invention are clearly and completely described in conjunction with the drawings of the specification. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments.
[0024] Embodiment 1:
[0025] (1) 400 mg of polyacrylonitrile and 100 mg of polymethyl methacrylate were dissolved in N,N-dimethylformamide at 60 °C. After cooling to room temperature, 250 mg of nickel acetate tetrahydrate was added and stirred continuously until a uniform spinning solution was formed. Subsequently, electrospinning was performed at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber film was collected on an aluminum foil about 20 cm away from the tip of the syringe.
[0026] (2) The obtained nanofiber membrane was pre-oxidized in air at 250 °C for 2 h in a tube furnace, and then carbonized at 800 °C in an Ar atmosphere for 2 h to obtain Ni-PCNFs 0.2 .
[0027] (3) Dissolve 34.4 mg of anhydrous sodium selenite in 15 mL of water, add 183 μL of hydrazine hydrate to prepare a uniform solution A, and stir vigorously for 20 min. 0.2 Ultrasonic dispersion was performed in 10 mL of water, and 0.025 mmol of nickel acetate was added after dispersion to obtain dispersion B. Subsequently, A and B were mixed and vigorously stirred for 20 min, and then transferred to a reactor for selenization reaction at 180 ° C for 8 h. The product was washed with water and ethanol several times and then dried in an oven at 50 ° C to obtain Ni-PCNFs 0.2 @NiSe-1 composite nanofibers.
[0028] Embodiment 2:
[0029] (1) 400 mg of polyacrylonitrile and 100 mg of polymethyl methacrylate were dissolved in N, N-dimethylformamide at 60 °C. After cooling to room temperature, 250 mg of nickel acetate tetrahydrate was added and stirred continuously until a uniform spinning solution was formed. Subsequently, electrospinning was performed at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber membrane was collected on an aluminum foil about 20 cm away from the tip of the syringe. (2) The obtained nanofiber membrane was pre-oxidized in a tubular furnace at 250 °C in air for 2 h, and then heated to 800 °C in an Ar atmosphere for carbonization for 2 h to obtain Ni-PCNFs. 0.2 .
[0030] (3) Dissolve 34.4 mg of anhydrous sodium selenite in 15 mL of water, add 183 μL of hydrazine hydrate to prepare a uniform solution A, and stir vigorously for 20 min. 0.2 Ultrasonic dispersion was performed in 10 mL of water, and 0.05 mmol of nickel acetate was added after dispersion to obtain dispersion B. A and B were then mixed and vigorously stirred for 20 min and transferred to a reactor for selenization reaction at 180 °C for 8 h. The product was washed with water and ethanol several times and dried in an oven at 50 °C to obtain Ni-PCNFs 0.2@NiSe-2 composite nanofibers.
[0031] Embodiment 3:
[0032] (1) 500 mg of polyacrylonitrile was dissolved in N,N-dimethylformamide at 60 °C, and after cooling to room temperature, 250 mg of nickel acetate tetrahydrate was added and stirred continuously until a uniform spinning solution was formed. Subsequently, electrospinning was performed at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber film was collected on an aluminum foil about 20 cm away from the tip of the syringe.
[0033] (2) The obtained nanofiber membrane was pre-oxidized in a tube furnace at 250 °C in air for 2 h, and then heated to 800 °C in an Ar gas atmosphere for carbonization for 2 h to obtain nickel / carbon nanofibers (Ni-CNFs).
[0034] (3) 34.4 mg of anhydrous sodium selenite was dissolved in 15 mL of water, and 183 μL of hydrazine hydrate was added to prepare a uniform solution A, which was vigorously stirred for 20 min. Subsequently, 5 mg of Ni-CNFs was ultrasonically dispersed in 10 mL of water, and 0.05 mmol of nickel acetate was added after dispersion to obtain dispersion B. Subsequently, A and B were mixed and vigorously stirred for 20 min and then transferred to a reactor for selenization reaction at 180 ° C for 8 h. The product was washed with water and ethanol several times and then dried in an oven at 50 ° C to obtain Ni-CNFs@NiSe-2 composite nanofibers.
[0035] Embodiment 4:
[0036] (1) 450 mg of polyacrylonitrile and 50 mg of polymethyl methacrylate were dissolved in N,N-dimethylformamide at 60 °C. After cooling to room temperature, 250 mg of nickel acetate tetrahydrate was added and stirred continuously until a uniform spinning solution was formed. Subsequently, electrospinning was performed at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber film was collected on an aluminum foil about 20 cm away from the tip of the syringe.
[0037] (2) The obtained nanofiber membrane was pre-oxidized in air at 250 °C for 2 h in a tube furnace, and then carbonized at 800 °C in an Ar atmosphere for 2 h to obtain Ni-PCNFs 0.1 .
[0038] (3) Dissolve 34.4 mg of anhydrous sodium selenite in 15 mL of water, add 183 μL of hydrazine hydrate to prepare a uniform solution A, and stir vigorously for 20 min. Then, add 5 mg of Ni-PCNF 0.1Ultrasonic dispersion was performed in 10 mL of water, and 0.05 mmol of nickel acetate was added after dispersion to obtain dispersion B. A and B were then mixed and vigorously stirred for 20 min and transferred to a reactor for selenization reaction at 180 °C for 8 h. The product was washed with water and ethanol several times and dried in an oven at 50 °C to obtain Ni-PCNFs 0.1 @NiSe-2 composite nanofibers.
[0039] Application Example 1:
[0040] The UOR catalytic activity of the prepared catalyst was tested by a three-electrode system. 0.2 @NiSe-2, for example, exhibits excellent UOR activity in a 1M KOH solution containing 0.33M urea, reaching 20mAcm at a potential of 1.37Vvs.RHE. -2 The stability of the Ni-PCNFs0.2@NiSe-2 catalyst prepared in Example 2 was tested. -2 The material can be stable for 48 h at a current density of , indicating that the material developed in the present invention has excellent UOR catalytic performance.
[0041] Application Example 2:
[0042] Ni-PCNFs prepared in Example 2 0.2 @NiSe-2 and commercial Pt / C were used as anode and cathode, respectively, to produce hydrogen by splitting water in 1M KOH solution. A potential of 1.56 V was required to reach 10 mA cm -2 The current density of Ni-PCNFs prepared in Example 2 0.2 @NiSe-2 and commercial Pt / C were used as anode and cathode, respectively, in a 1M KOH solution containing 0.33M urea for urea oxidation-assisted water splitting to produce hydrogen. Only 1.39V was required to achieve 10mAcm -2 The current density is much lower than 1.56 V, indicating that the material developed by the present invention has excellent urea oxidation-assisted full water splitting hydrogen production performance.
Claims
1. A method for controllably growing Ni0.85Se on the surface of carbon nanofibers and its application. The preparation method is as follows: (1) Prepare the electrospinning precursor solution. Dissolve a certain proportion of polyacrylonitrile and polymethyl methacrylate in N,N-dimethylformamide at 60 ºC. After cooling to room temperature, add nickel acetate tetrahydrate and stir continuously until a uniform spinning precursor solution is formed. Subsequently, electrospinning is performed at a voltage of 15 KV, and a light green nickel precursor / polymer nanofiber membrane is collected on an aluminum foil about 20 cm away from the tip of the syringe. (2) The nanofiber membrane is placed in a quartz crucible and pre-oxidized at 250 ºC in air for 2 h in a tube furnace. Then, the temperature is raised to 800 ºC in an Ar atmosphere and carbonized for 2 h to obtain porous nickel / carbon nanofibers (Ni-PCNFs). (3) Dissolve 34.4 mg of anhydrous sodium selenite in 15 mL of water, and add 183 μL of hydrazine hydrate to prepare a uniform solution A. Stir vigorously for 20 min. Subsequently, 5 mg of Ni-PCNFs was ultrasonically dispersed in 10 mL of water, and different molar amounts of nickel acetate were added after dispersion to obtain dispersion B. Subsequently, A and B were mixed and vigorously stirred for 20 min and then transferred to a reactor for selenization reaction at 180 ºC for 8 h. The product was washed with water and ethanol several times and then dried in an oven at 50 ℃ to obtain Ni-PCNFs@NiSe composite nanofibers.
2. The method of controlling the growth of Ni on the surface of carbon nanofibers according to claim 1 0.85 Se method, in the step (1), the mass fraction of polymethyl methacrylate is controlled to be 0, 0.1, 0.2, 0.3 (mass of polymethyl methacrylate: total mass of polymer).
3. The carbon nanofiber surface controllably grown Ni according to claim 1 0.85 Se method, the molar concentration of nickel acetate in the hydrothermal system in step (4) is 1, 2, 3, 4 mM.