Preparation method and application of cobalt-boron (CoB) hydrogen evolution electrocatalyst based on foamed nickel
By preparing CoB hydrogen evolution electrocatalysts on nickel foam substrates, the problems of few active sites and poor conductivity of TMBs electrodes were solved, achieving low-cost and high-efficiency electrocatalytic performance suitable for commercial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHENZHEN ZHONGKE HYDROGEN TECH CO LTD
- Filing Date
- 2023-05-05
- Publication Date
- 2026-04-21
AI Technical Summary
Existing TMBs electrodes have few active sites, poor conductivity, high preparation costs, and poor catalytic performance.
CoB hydrogen evolution electrocatalyst was prepared by using nickel foam as a substrate and generating cobalt boride through the reduction reaction of cobalt chloride hexahydrate and sodium borohydride. Its morphology was then controlled by ultrasonic reaction and argon gas introduction.
The prepared CoB hydrogen evolution electrocatalyst has low hydrogen evolution overpotential, good conductivity, stability and high HER performance, making it suitable for commercial application.
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Figure CN116479456B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochemical catalysis technology, specifically relating to a method for preparing and applying a CoB hydrogen evolution electrocatalyst based on nickel foam. Background Technology
[0002] With the continuous depletion of traditional fossil fuels, one of the major challenges facing the rapid development of human civilization is the exploration of efficient, clean, and sustainable new energy sources. Hydrogen is considered one of the most promising alternatives to fossil fuels due to its high energy density, environmental friendliness, and renewable energy advantages. Currently, water electrolysis for hydrogen production is considered a mainstream technology due to its stability, low pollution, and high efficiency. However, the lack of highly active and stable electrocatalysts limits the development of the electrocatalytic hydrogen production industry. At present, noble metal-based catalysts are the most widely used electrocatalysts for electrocatalytic hydrogen production. In the long term, however, inexpensive and efficient transition metal-based materials are one of the most promising alternatives for electrodes in industrial water electrolyzers. Therefore, there is an urgent need to research low-cost, rare-earth-rich, efficient, and stable transition metal electrocatalysts for hydrogen production.
[0003] Recently, transition metal borides (TMBs) have attracted considerable interest as a novel alternative to Pt catalysts and have proven to be effective HER electrocatalysts due to their significant activity, high conductivity, long-term stability, and abundant active sites. Co-based compounds, with their advantages of being environmentally friendly, abundant, thermally stable, low-cost, and highly active, have become ideal catalysts for electrocatalytic hydrogen production. Meanwhile, the reverse charge transfer from boron to transition metals significantly increases the density of metal as HER active sites, further enhancing the performance of electrocatalytic hydrogen production.
[0004] Therefore, CoB is currently considered a promising candidate to replace platinum due to its excellent adsorption and desorption performance in the electrocatalyst hydrogen evolution reaction (HER). However, current CoB synthesis requires the use of polymer binders to immobilize the catalyst powder on a substrate, which leads to partial coverage of active sites, easy catalyst separation, and reduced catalyst conductivity, resulting in a significant decrease in catalyst performance. Therefore, further significantly improving the catalytic performance of TMBs to meet practical applications remains a major challenge. Summary of the Invention
[0005] The purpose of this invention is to solve the problems of existing TMBs electrodes, such as few active sites, poor conductivity, high preparation cost, and poor catalytic effect, and to provide a method for preparing CoB hydrogen evolution electrocatalyst based on nickel foam and its application.
[0006] The specific technical solution is as follows:
[0007] The first aspect of this invention provides a method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam, comprising the following steps:
[0008] Pretreatment of nickel foam substrate: The nickel foam substrate is pretreated to remove oil and oxide layer from the surface of the nickel foam;
[0009] Preparation of mixed solutions: Mix cobalt chloride hexahydrate, ammonium fluoride, ammonia and deionized water to obtain mixed solution A; mix sodium borohydride, sodium hydroxide and deionized water to obtain mixed solution B; preferably, when mixing sodium borohydride, sodium hydroxide and deionized water, the stirring speed is 60-80 r / min and the stirring time is 20-50 min.
[0010] Chemical deposition: ① The pretreated nickel foam substrate is immersed in a mixed solution A with argon gas introduced into it; ② The mixed solution B is poured into the system of step ①, and ultrasonic treatment is performed in an ice bath. After the reaction is completed, the substrate is dried to obtain the CoB electrocatalyst based on nickel foam.
[0011] Furthermore, the nickel foam substrate is pure nickel or a nickel alloy; the nickel foam has a width of 1-1.5 cm, a length of 1-2 cm, a thickness of 0.04-25 mm, and a porosity ≥98%.
[0012] Further, the pretreatment method for the nickel foam substrate is as follows: 1) Immerse the nickel foam substrate in an acetone solution for ultrasonic degreasing, and then ultrasonically clean it with deionized water to obtain a degreased nickel foam substrate; 2) Immerse the degreased nickel foam substrate in a hydrochloric acid solution with a molar concentration of 2M to 8M for ultrasonic removal of the oxide layer on the surface of the nickel foam, and then ultrasonically clean it with deionized water; 3) Dry the ultrasonically cleaned nickel foam substrate for chemical deposition, or store the ultrasonically cleaned nickel foam substrate in a 0.1M to 0.5M nickel chloride solution for later use, and take it out and wash and dry it before chemical deposition.
[0013] Furthermore, in step 1), the ultrasonic power is 200W to 300W, the ultrasonic degreasing time is 5min to 10min, and the ultrasonic cleaning time is 2min to 5min.
[0014] In step 2), the ultrasonic power is 200W to 300W, the ultrasonic removal time for the nickel foam surface oxide layer is 10min to 15min, and the ultrasonic cleaning time is 5min to 10min.
[0015] Further, in mixed solution A, the mass ratio of cobalt chloride hexahydrate to ammonium fluoride is (0.65g~1.05g):(1.05g~1.35g), and the mass ratio of cobalt chloride hexahydrate, ammonia water volume, and deionized water volume is (0.65g~1.05g):(2.0mL~3.0mL):(20mL~50mL).
[0016] In mixed solution B, the mass ratio of sodium borohydride to sodium hydroxide is (0.325g~1.35g):(0.10g~0.30g), and the mass ratio of sodium borohydride to deionized water is (0.325g~1.35g):(20mL~50mL).
[0017] Furthermore, in step ①, the argon gas introduction rate is 15-30 mL / min. -1 The soaking time in mixed solution A is 5 to 10 minutes.
[0018] Furthermore, in step ②, the power of the ice bath ultrasound is 200W to 300W, and the duration is 30-50 minutes.
[0019] A second aspect of the present invention provides a CoB hydrogen evolution electrocatalyst based on nickel foam obtained by the preparation method described above.
[0020] A third aspect of the present invention provides a working electrode for electrocatalytic hydrogen evolution, the working electrode being prepared from the CoB electrocatalyst based on nickel foam.
[0021] The fourth aspect of the present invention provides the application of the CoB hydrogen evolution electrocatalyst based on nickel foam or the working electrode of the electrocatalytic hydrogen evolution in the preparation of hydrogen.
[0022] The beneficial effects of this invention are as follows:
[0023] 1. This invention provides a method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam. Cobalt boride is generated by the reduction reaction of cobalt chloride hexahydrate and sodium borohydride. At the same time, its morphology is controlled by means of ultrasonic reaction and argon gas introduction. The preparation process is easy to operate, low in cost and low in equipment investment, and is suitable for commercial promotion and application.
[0024] 2. The CoB hydrogen evolution electrocatalyst prepared by this invention has low hydrogen evolution overpotential, good corrosion resistance, good stability, and good conductivity, which has important theoretical and practical significance.
[0025] 3. This invention provides a CoB hydrogen evolution electrocatalyst, which has the advantages of high controllability, mild reaction conditions, small footprint and environmental friendliness;
[0026] 4. The CoB hydrogen evolution electrocatalyst prepared in this invention exhibits high HER performance at a current density of 10 mA·cm⁻¹. -2 The hydrogen evolution overpotential was 32mV, and after 42 hours of continuous chronocurrent stability testing, the hydrogen evolution overpotential remained almost unchanged. Attached Figure Description
[0027] Figure 1 Linear voltammetric scan of the CoB composite electrocatalyst electrode prepared in Example 1;
[0028] Figure 2 These are scanning electron microscope (SEM) images of the CoB composite electrocatalyst prepared in Example 1 at different magnifications.
[0029] Figure 3 Linear voltammetric scan of the CoB composite electrocatalyst electrode prepared in Example 2;
[0030] Figure 4 These are scanning electron microscope (SEM) images of the CoB composite electrocatalyst prepared in Example 2 at different magnifications.
[0031] Figure 5 The image shows a series of graphs of the chronoamperometry and linear sweep voltammetry before and after the chronoamperometry test for the CoB composite electrocatalyst electrode prepared in Example 2.
[0032] Figure 6 Linear voltammetric scan of the CoB composite electrocatalyst electrode prepared in Example 3;
[0033] Figure 7 The images are scanning electron microscope (SEM) images of the CoB composite electrocatalyst prepared in Example 3 at different magnifications. Detailed Implementation
[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.
[0035] Unless otherwise specified, all raw materials used in the various embodiments of this invention are commercially available.
[0036] Example 1
[0037] This embodiment provides a method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam. The raw materials used are: cobalt chloride hexahydrate (0.85g), ammonium fluoride (1.35g), ammonia (2mL), sodium borohydride (1.3g), sodium hydroxide (0.15g), and deionized water (100mL). The preparation is carried out according to the following steps:
[0038] S1. Pretreatment of the nickel foam substrate:
[0039] The nickel foam substrate was cut into 1.5cm × 1.5cm samples and immersed in acetone solution (analytical grade) for ultrasonic degreasing for 10 min. Then, it was ultrasonically cleaned with deionized water for 5 min to obtain the degreased nickel foam substrate. The degreased nickel foam substrate was then immersed in a 4M hydrochloric acid solution and ultrasonically cleaned for 10 min to remove the oxide layer on the surface of the nickel foam. After removal, it was ultrasonically cleaned with deionized water for 5 min. The ultrasonically cleaned nickel foam substrate was then stored in a 0.1M nickel chloride solution for later use. The ultrasonic power in this step was 200W.
[0040] S2. Preparation of the mixed solution:
[0041] Mix 0.85 g of cobalt chloride hexahydrate, 1.35 g of ammonium fluoride, 2 mL of ammonia, and 50 mL of deionized water, and stir continuously at 80 rpm for 30 min to obtain mixed solution A. Mix 1.3 g of sodium borohydride, 0.15 g of sodium hydroxide, and 50 mL of deionized water, and stir continuously at 100 rpm for 10 min to obtain mixed solution B.
[0042] S3, Chemical Deposition:
[0043] ① Take the nickel foam substrate to be used out of the 0.1M nickel chloride solution, wash and dry it, and then soak it in mixed solution A with argon gas for 5 minutes.
[0044] ② Slowly pour mixed solution B into the system of step ① and perform sonication in an ice bath. After reacting for 30 minutes, remove the nickel foam from which the CoB catalyst is grown.
[0045] ③ The catalyst obtained in step ② was rinsed with deionized water. Then, it was dried in a vacuum drying oven for 1 hour to obtain a CoB hydrogen evolution electrocatalyst based on nickel foam. This is denoted as Co. 0.85 B 1.3 .
[0046] Co in this embodiment 1 0.85 B 1.3 The hydrogen evolution material was directly used as the working electrode in the electrocatalytic hydrogen evolution reaction, and its electrocatalytic performance was studied. Specifically:
[0047] (1) Prepare a 1.0 M potassium hydroxide solution as the electrolyte for electrocatalysis, and use 25 mL·min -1 Nitrogen gas was introduced at a rate of 10 min to saturate the solution with nitrogen. Co 0.85 B 1.3 An Ag / AgCl electrode and a platinum electrode were connected to an electrochemical workstation as the working electrode, reference electrode, and counter electrode, respectively. The voltage was measured at 5 mV·s. -1 The electrode material was subjected to linear voltammetry testing at a scan rate of [missing information]. Figure 1 As shown ( Figure 1 (For linear sweep voltammetry curves), Co 0.85 B 1.3 At a current density of 10 mA·cm -2 The overpotential is 78mV.
[0048] (2) Co 0.85 B 1.3 Scanning electron microscope images at different magnifications, such as Figure 2 As shown, from Figure 2 As can be seen from a, Co 0.85 B 1.3 The surface is composed of irregular crack-like structures, with micron-sized spherical particles randomly distributed on it. Higher magnification indicates ( Figure 2 b) The catalyst surface is composed of densely packed spherical particles of about 300 nm.
[0049] Example 2
[0050] This embodiment provides a method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam. The raw materials used are: cobalt chloride hexahydrate (0.85g), ammonium fluoride (1.35g), ammonia (2mL), sodium borohydride (0.65g), sodium hydroxide (0.15g), and deionized water (100mL). The preparation is carried out according to the following steps:
[0051] S1. Pretreatment of the nickel foam substrate:
[0052] The nickel foam substrate was cut into 1.5cm × 1.5cm samples, immersed in acetone solution, and ultrasonically degreased for 10 min. Then, it was ultrasonically cleaned with deionized water for 5 min to obtain the degreased nickel foam substrate. The degreased nickel foam substrate was then immersed in an 8M hydrochloric acid solution and ultrasonically cleaned for 10 min to remove the oxide layer on the surface of the nickel foam. After removal, it was ultrasonically cleaned with deionized water for 5 min. The ultrasonically cleaned nickel foam substrate was then stored in a 0.5M nickel chloride solution for later use. The ultrasonic power in this step was 300W.
[0053] S2. Preparation of the mixed solution:
[0054] Mix 0.85 g of cobalt chloride hexahydrate, 1.35 g of ammonium fluoride, 2 mL of ammonia, and 50 mL of deionized water, and stir continuously at 80 rpm for 30 min to obtain mixed solution A. Mix 0.65 g of sodium borohydride, 0.15 g of sodium hydroxide, and 50 mL of deionized water, and stir continuously at 100 rpm for 10 min to obtain mixed solution B.
[0055] S3, Chemical Deposition:
[0056] ① Take the foamed nickel substrate to be used out of the 0.5M nickel chloride solution, wash and dry it, and then soak it in mixed solution A for 10 minutes.
[0057] ② Slowly pour mixed solution B into the system of step ① and perform sonication in an ice bath. After reacting for 30 minutes, remove the nickel foam from which the CoB catalyst is grown.
[0058] ③ The catalyst obtained in step ② was rinsed with deionized water. Then, it was dried in a vacuum drying oven for 1 hour to obtain a CoB hydrogen evolution electrocatalyst based on nickel foam. This is denoted as Co. 0.85 B 0.65 .
[0059] Co in this embodiment 2 0.85 B 0.65 The hydrogen evolution material was directly used as the working electrode in the electrocatalytic hydrogen evolution reaction, and its electrocatalytic performance was studied. Specifically:
[0060] (1) Prepare a 1.0 M potassium hydroxide solution as the electrolyte for electrocatalysis, and use 25 mL·min -1 Nitrogen gas was introduced at a rate of 10 min to saturate the solution with nitrogen. Co 0.85 B 0.65 An Ag / AgCl electrode and a platinum electrode were connected to an electrochemical workstation as the working electrode, reference electrode, and counter electrode, respectively. The voltage was measured at 5 mV·s. -1 The electrode material was subjected to linear voltammetry testing at a scan rate of [missing information]. Figure 3 As shown ( Figure 3 (For linear sweep voltammetry curves), Co 0.85 B 0.65 At a current density of 10 mA·cm -2 The overpotential is 32mV.
[0061] (2) Co 0.85 B 0.65 Scanning electron microscope images at different magnifications, such as Figure 4 As shown, from Figure 4 As can be seen from a, Co 0.85 B 0.65 The surface has a "paper-wrinkled" structure composed of nanosheets, and is uniform and free of impurities. Higher magnification indicates ( Figure 4 b) The catalyst surface is composed of nanosheets, and nanoscale pore structures can be observed on the nanosheets.
[0062] (3) Prepare a 1.0 M potassium hydroxide solution as the electrolyte for electrocatalysis, and use 25 mL·min -1 Nitrogen gas was introduced at a rate of 10 min to saturate the solution with nitrogen. The treated Co... 0.85 B0.65 Ag / AgCl electrode and platinum electrode were used as working electrode, reference electrode and counter electrode, respectively, and connected to an electrochemical workstation for chronocurrent stability testing. Figure 5 As shown in the illustration, Co 0.85 B 0.65 The current remained stable over 42 hours (voltage condition: 0.093V vs Ag / AgCl). Furthermore, the linear sweep voltammetry curves before and after the stability test showed almost no shift, further confirming the presence of Co. 0.85 B 0.65 It has good stability.
[0063] Example 3
[0064] This embodiment provides a method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam. The raw materials used are: cobalt chloride hexahydrate (0.85g), ammonium fluoride (1.35g), ammonia (2mL), sodium borohydride (0.32g), sodium hydroxide (0.15g), and deionized water (100mL). The preparation is carried out according to the following steps:
[0065] S1. Pretreatment of the nickel foam substrate:
[0066] The nickel foam substrate was cut into 1.5cm × 1.5cm samples, immersed in acetone solution, and ultrasonically degreased for 10 min. Then, it was ultrasonically cleaned with deionized water for 5 min to obtain the degreased nickel foam substrate. The degreased nickel foam substrate was then immersed in a 4M hydrochloric acid solution and ultrasonically cleaned for 10 min to remove the oxide layer on the surface of the nickel foam. After removal, it was ultrasonically cleaned with deionized water for 5 min. The ultrasonically cleaned nickel foam substrate was then stored in a 0.1M nickel chloride solution for later use. The ultrasonic power in this step was 200W.
[0067] S2. Preparation of the mixed solution:
[0068] Mix 0.85 g of cobalt chloride hexahydrate, 1.35 g of ammonium fluoride, 2 mL of ammonia, and 50 mL of deionized water, and stir continuously at 80 rpm for 30 min to obtain mixed solution A. Mix 0.325 g of sodium borohydride, 0.15 g of sodium hydroxide, and 50 mL of deionized water, and stir continuously at 100 rpm for 10 min to obtain mixed solution B.
[0069] S3, Chemical Deposition:
[0070] ① Take the nickel foam substrate to be used out of the 0.1M nickel chloride solution, wash and dry it, and then soak it in mixed solution A for 5 minutes.
[0071] ② Slowly pour mixed solution B into the system of step ① and perform sonication in an ice bath. After reacting for 30 minutes, remove the nickel foam from which the CoB catalyst is grown.
[0072] ③ The catalyst obtained in step ② was rinsed with deionized water. Then, it was dried in a vacuum drying oven for 1 hour to obtain a CoB hydrogen evolution electrocatalyst based on nickel foam. This is denoted as Co. 0.85 B 0.325 .
[0073] Co in this embodiment 3 0.85 B 0.325 The hydrogen evolution material was directly used as the working electrode in the electrocatalytic hydrogen evolution reaction, and its electrocatalytic performance was studied. Specifically:
[0074] (1) Prepare a 1.0 M potassium hydroxide solution as the electrolyte for electrocatalysis, and use 25 mL·min -1 Nitrogen gas was introduced at a rate of 10 min to saturate the solution with nitrogen. Co 0.85 B 0.325 An Ag / AgCl electrode and a platinum electrode were connected to an electrochemical workstation as the working electrode, reference electrode, and counter electrode, respectively. The voltage was measured at 5 mV·s. -1 The electrode material was subjected to linear voltammetry testing at a scan rate of [missing information]. Figure 6 As shown ( Figure 6 (For linear sweep voltammetry curves), Co 0.85 B 0.325 At a current density of 10 mA·cm -2 The overpotential is 67mV.
[0075] (2) Co 0.85 B 0.325 Scanning electron microscope images at different magnifications, such as Figure 7 As shown, from Figure 7 As can be seen from a, Co 0.85 B 0.325 The surface is composed of random nanoparticles and contains a small number of cracks. Higher magnification shows ( Figure 7 (b) The catalyst surface is composed of smooth nanosheets. At the same time, a large number of nanosheets agglomerate.
[0076] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A method for preparing a CoB hydrogen evolution electrocatalyst based on nickel foam, characterized in that, Includes the following steps: Pretreatment of nickel foam substrate: The nickel foam substrate is pretreated to remove oil and oxide layer from the surface of the nickel foam; Preparation of mixed solutions: Mix cobalt chloride hexahydrate, ammonium fluoride, ammonia, and deionized water to obtain mixed solution A; mix sodium borohydride, sodium hydroxide, and deionized water to obtain mixed solution B; Chemical deposition: ① The pretreated nickel foam substrate is immersed in a mixed solution A with argon gas introduced; ② The mixed solution B is poured into the system of step ①, and ultrasonic treatment is performed in an ice bath. After the reaction is completed, the substrate is dried to obtain the CoB electrocatalyst based on nickel foam. In step ①, the argon gas introduction rate is 15-30 mL / min. -1 The soaking time in mixed solution A is 5~10 min; In step ②, the power of the ice bath ultrasound is 200 W~300 W, and the time is 30-50 min; In mixed solution A, the mass ratio of cobalt chloride hexahydrate to ammonium fluoride is (0.65 g~1.05 g):(1.05 g~1.35 g), and the mass ratio of cobalt chloride hexahydrate, ammonia water, and deionized water is (0.65 g~1.05 g):(2.0 mL~3.0 mL):(20 mL~50 mL). In mixed solution B, the mass ratio of sodium borohydride to sodium hydroxide is (0.325 g~1.35 g):(0.10 g~0.30 g), and the mass ratio of sodium borohydride to deionized water is (0.325 g~1.35 g):(20 mL~50 mL).
2. The preparation method according to claim 1, characterized in that, The nickel foam substrate is pure nickel or a nickel alloy; the nickel foam has a width of 1~1.5 cm, a length of 1~2 cm, a thickness of 0.04~25 mm, and a porosity ≥98%.
3. The preparation method according to claim 1, characterized in that, The pretreatment method for the nickel foam substrate is as follows: 1) Immerse the nickel foam substrate in acetone solution and ultrasonically remove oil, then ultrasonically clean it with deionized water to obtain the degreased nickel foam substrate; 2) Immerse the degreased nickel foam substrate in hydrochloric acid solution with a molar concentration of 2 M to 8 M and ultrasonically remove the oxide layer on the surface of the nickel foam, then ultrasonically clean it with deionized water; 3) Dry the ultrasonically cleaned nickel foam substrate and use it for chemical deposition, or store the ultrasonically cleaned nickel foam substrate in 0.1 M to 0.5 M nickel chloride solution for later use, and take it out and wash and dry it before chemical deposition.
4. The preparation method according to claim 3, characterized in that, In step 1), the ultrasonic power is 200 W to 300 W, the ultrasonic degreasing time is 5 min to 10 min, and the ultrasonic cleaning time is 2 min to 5 min. In step 2), the ultrasonic power is 200 W to 300 W, the ultrasonic removal time for the nickel foam surface oxide layer is 10 min to 15 min, and the ultrasonic cleaning time is 5 min to 10 min.
5. The CoB hydrogen evolution electrocatalyst based on nickel foam obtained by the preparation method according to any one of claims 1-4.
6. A working electrode for electrocatalytic hydrogen evolution, characterized in that, The working electrode is formed from the CoB electrocatalyst based on nickel foam as described in claim 5.
7. The application of the CoB hydrogen evolution electrocatalyst based on nickel foam as described in claim 5 or the working electrode for electrocatalytic hydrogen evolution as described in claim 6 in the preparation of hydrogen.