An electrolysis catalyst for water and its preparation method
By growing transition metal hydroxides in situ on a foamed iron substrate and loading noble metals, the problem of high overpotential and poor stability of water electrolysis catalysts under high current density was solved, and a water electrolysis catalyst with low overpotential and high stability was realized, which is suitable for industrial production.
Patent Information
- Application Number
- CN202211281564.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-10-19
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2042-10-19
AI Technical Summary
Existing water electrolysis catalysts have high overpotentials and poor stability at high current densities, making it difficult to simultaneously possess excellent hydrogen evolution performance and high stability.
A precursor was prepared by in-situ growth of transition metal hydroxides on a foamed iron substrate using an etching method. Then, a noble metal was loaded onto the precursor by a solution immersion reduction method to form a stable self-supporting structure.
It achieves high stability at high current density under low overpotential, meeting the needs of industrial production. The catalyst achieves a high current density of 500 mA/cm2 at an overpotential of 94 mV and operates stably for 1300 h.
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Figure CN115679365B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of materials, and more specifically, relates to an electrolysis catalyst for water and its preparation method. Background Technology
[0002] With the scarcity of fossil fuels and the urgent need for carbon emission reduction worldwide, finding new renewable and clean energy sources is crucial. Hydrogen energy has attracted widespread attention due to its wide availability, high energy density, and pollution-free combustion products. Among these, water electrolysis for hydrogen production is considered to have the potential for large-scale industrial hydrogen production due to its high energy efficiency, pollution-free production process, and high product purity, showing promising application prospects. However, industrial production also presents new challenges to water electrolysis technology, especially the cathode for hydrogen evolution: maintaining low overpotential and high stability under high current density.
[0003] Currently, the best-performing hydrogen evolution catalysts are noble metal-based materials, mostly in powder form. Electrode fabrication requires the use of conductive binders, which, while providing high hydrogen evolution performance, makes them prone to detachment from the substrate and results in poor stability. In contrast, transition metal hydroxides can easily grow in situ on the substrate, forming a stable, self-supporting structure with high stability. However, their drawback is a relatively poor hydrogen evolution capability. Summary of the Invention
[0004] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides an electrolytic water catalyst and its preparation method, thereby solving the technical problem that existing electrolytic water catalysts are difficult to simultaneously possess superior hydrogen evolution performance and stability.
[0005] To achieve the above objectives, according to a first aspect of the present invention, a water electrolysis catalyst and a method for preparing the same are provided, comprising:
[0006] S1, a precursor is prepared by in-situ growth of transition metal hydroxides on a foamed iron substrate using an etching method;
[0007] S2, a water electrolysis catalyst is obtained by loading noble metals onto the precursor through a solution immersion reduction method.
[0008] Preferably, step S1 includes:
[0009] Nickel chloride and sodium chloride were added to deionized water and stirred evenly. After adding cleaned foamed iron as a substrate, the mixture was removed and washed with deionized water and anhydrous ethanol, and then dried under vacuum to obtain the precursor.
[0010] Preferably, the size of the foamed iron is 1mm*20mm*40mm, the volume of the deionized water is 100mL, and the amounts of sodium chloride and nickel chloride are 10mmol and 30mmol, respectively.
[0011] Preferably, the cleaning method for the foamed iron is as follows: ultrasonic cleaning with anhydrous ethanol and hydrochloric acid for 10 minutes each, followed by rinsing with deionized water several times.
[0012] Preferably, the corrosion reaction temperature is room temperature and the reaction time is 12 hours.
[0013] Preferably, step S2 includes:
[0014] The precursor was immersed in a noble metal salt aqueous solution for reduction reaction, then removed, washed with deionized water and ethanol respectively, and dried under vacuum to obtain the water electrolysis catalyst.
[0015] Preferably, the reduction reaction temperature is room temperature and the reaction time is 10 hours; the noble metal salt aqueous solution is a ruthenium chloride aqueous solution.
[0016] Preferably, the precursor has a size of 1cm*2cm, and the ruthenium chloride aqueous solution has a concentration of 8mg / mL and a volume of 2mL.
[0017] Preferably, the transition metal hydroxide is a nickel-iron hydroxide.
[0018] According to a second aspect of the present invention, a water electrolysis catalyst is provided, which is prepared by the preparation method described in the first aspect.
[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:
[0020] Therefore, we combine the advantages of both to grow layered hydroxides in situ on a conductive substrate, maintaining a stable self-supporting structure, while loading a small amount of noble metals to utilize their excellent hydrogen evolution performance, ultimately meeting the requirements of industrial production: high current density, low overpotential, and high stability.
[0021] The purpose of this invention is to improve the hydrogen evolution performance and stability of water electrolysis catalysts to meet the needs of industrial production. This invention uses common and inexpensive commercial foamed iron as raw material, prepares transition metal hydroxide precursors by corrosion method, and then loads noble metals by immersion in noble metal salt aqueous solution. The process is simple and has the potential for large-scale industrial production. The prepared catalyst can achieve high current density and high stability at low overpotential.
[0022] The process is simple, has the foundation for large-scale production, and has high potential for industrial application. The prepared catalyst can achieve a high current density of 500 mA / cm2 at an overpotential of 94 mV and can operate stably for at least 1300 h after being assembled into an electrolytic cell. Attached Figure Description
[0023] Figure 1 The polarization curves of the catalysts prepared according to Examples 1, 2, and 3 of this invention are shown.
[0024] Figure 2 This is a potential-time chronopotential curve of the electrolytic cell assembled according to Example 4 of the present invention. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0026] This invention provides a method for preparing a water electrolysis catalyst, comprising:
[0027] S1, a precursor was prepared by in-situ growth of transition metal hydroxides on a foamed iron substrate using an etching method.
[0028] S2, a water electrolysis catalyst is obtained by loading noble metals onto the precursor through a solution immersion reduction method.
[0029] Specifically, the water electrolysis catalyst is a transition metal hydroxide supported noble metal catalyst. The catalyst is grown in situ on a foamed iron substrate using an etching method to grow a transition metal hydroxide precursor, and then a noble metal is loaded onto the precursor by a solution immersion reduction method.
[0030] Preferably, step S1 includes:
[0031] Nickel chloride and sodium chloride were added to deionized water and stirred evenly. After adding cleaned foamed iron as a substrate, the mixture was removed and washed with deionized water and anhydrous ethanol, and then dried under vacuum to obtain the precursor.
[0032] Specifically, the precursor is prepared by corrosion method. A certain amount of nickel chloride and sodium chloride are added to a certain volume of deionized water and stirred evenly. Then, cleaned foamed iron is added as a substrate. After reacting at a certain temperature for a certain time, the substrate is washed with deionized water and anhydrous ethanol respectively, and finally dried in a vacuum environment.
[0033] Preferably, the size of the foamed iron is 1mm*20mm*40mm, the volume of the deionized water is 100mL, and the amounts of sodium chloride and nickel chloride are 10mmol and 30mmol, respectively.
[0034] Preferably, the cleaning method for the foamed iron is as follows: ultrasonic cleaning with anhydrous ethanol and 1 mol / L hydrochloric acid for 10 min each, followed by rinsing with deionized water several times.
[0035] Preferably, the corrosion reaction temperature is room temperature and the reaction time is 12 hours.
[0036] Preferably, step S2 includes:
[0037] The precursor was immersed in a noble metal salt aqueous solution for reduction reaction, then removed, washed with deionized water and ethanol respectively, and dried under vacuum to obtain the water electrolysis catalyst.
[0038] Specifically, noble metals are loaded onto the precursor by solution immersion reduction method. A certain concentration of noble metal salt aqueous solution is prepared, the prepared precursor is immersed in it, reacted at a certain temperature for a period of time, and then taken out, washed with deionized water and ethanol respectively, and finally dried in a vacuum environment.
[0039] Preferably, the reduction reaction temperature is room temperature and the reaction time is 10 hours.
[0040] Preferably, the noble metal salt aqueous solution is a ruthenium chloride aqueous solution.
[0041] Preferably, the precursor has a size of 1cm*2cm, and the ruthenium chloride aqueous solution has a concentration of 8mg / mL and a volume of 2mL.
[0042] Preferably, the transition metal hydroxide is a nickel-iron hydroxide.
[0043] Specifically, precious metals can be loaded onto nickel-iron hydroxide grown in situ on a foamed iron substrate using a solution immersion reduction method.
[0044] This invention provides a water electrolysis catalyst, which is prepared using the preparation method described in any of the above embodiments.
[0045] To ensure the comparability of the data obtained from electrochemical tests, the following examples were all conducted on the CHI660D electrochemical workstation of Shanghai Chenhua Instrument Co., Ltd. The test conditions for Examples 1-3 were as follows: a carbon rod was used as the counter electrode, a mercury oxide electrode as the reference electrode, and the prepared catalyst as the working electrode, forming a three-electrode test system. The test electrolyte was 1 M KOH solution.
[0046] Example 1 includes the following steps:
[0047] 1) Clean the foamed iron with anhydrous ethanol and 1 mol / L HCl solution for 10 min to remove surface oil and oxides, then rinse several times with deionized water to remove surface acid.
[0048] 2) Add 10 mmol NaCl and 30 mmol NiCl2 to 100 mL of deionized water, stir well, and then put the washed foamed iron into it. After reacting at room temperature for 12 h, wash the obtained sample with deionized water and anhydrous ethanol, and then dry it under vacuum. The product obtained is the nickel iron hydroxide precursor, denoted as FNOH.
[0049] The prepared FNOH was used as the working electrode, with an area of 0.5 cm². 2 Linear scanning polarization curves were performed on the sample in 1 M KOH solution at a scan rate of 5 mV / s. The test results are as follows: Figure 1 As shown in FNOH.
[0050] Example 2 includes the following steps:
[0051] 1) Clean the foamed iron with anhydrous ethanol and 1 mol / L HCl solution for 10 min to remove surface oil and oxides, then rinse several times with deionized water to remove surface acid.
[0052] 2) The washed foamed iron was placed directly into a ruthenium chloride solution with a mass concentration of 8 mg / mL and left to stand for 10 h. After standing, it was taken out, washed with deionized water and anhydrous ethanol, and then dried under vacuum. The product obtained is the foamed iron loaded with the noble metal ruthenium, denoted as R-FF.
[0053] The prepared R-FF electrode with an area of 0.5 cm² was used as the working electrode. Linear scanning polarization curves were measured in 1 M KOH solution at a scan rate of 5 mV / s. The results are shown in the attached figure. Figure 1 As shown in R-FF.
[0054] Example 3 includes the following steps:
[0055] 1) Clean the foamed iron with anhydrous ethanol and 1 mol / L HCl solution for 10 min to remove surface oil and oxides, then rinse several times with deionized water to remove surface acid.
[0056] 2) Add 10 mmol NaCl and 30 mmol NiCl2 to 100 mL of deionized water, stir well, then add the washed foamed iron, react at room temperature for 12 h, wash the resulting sample with deionized water and anhydrous ethanol, and then dry under vacuum. The product obtained is the nickel iron hydroxide precursor.
[0057] 3) The prepared precursor was placed directly into a ruthenium chloride solution with a mass concentration of 8 mg / mL and allowed to stand for 10 h. After standing, it was taken out, washed with deionized water and anhydrous ethanol, and dried under vacuum. The product obtained was the nickel-iron hydroxide catalyst supported on the noble metal ruthenium, denoted as R-FNOH.
[0058] The prepared R-FNOH was used as the working electrode, with an area of 0.5 cm². 2 Linear scanning polarization curves were performed on the sample in 1 M KOH solution at a scan rate of 5 mV / s. The test results are as follows: Figure 1 As shown in R-FNOH.
[0059] The test results of Examples 1-3 show that loading the noble metal ruthenium can significantly reduce the hydrogen evolution overpotential of the catalyst, especially when ruthenium is loaded with nickel iron hydroxide, the catalyst has the best hydrogen evolution performance.
[0060] Example 4 includes the following steps:
[0061] 1) Clean the foamed iron with anhydrous ethanol and 1 mol / L HCl solution for 10 min to remove surface oil and oxides, then rinse several times with deionized water to remove surface acid.
[0062] 2) Add 10 mmol NaCl and 30 mmol NiCl2 to 100 mL of deionized water, stir well, and then put the washed foamed iron into it. After reacting at room temperature for 12 h, wash the obtained sample with deionized water and anhydrous ethanol, and then dry it under vacuum. The product obtained is the nickel iron hydroxide precursor, denoted as FNOH.
[0063] 3) The prepared precursor was placed directly into a ruthenium chloride solution with a mass concentration of 8 mg / mL and allowed to stand for 10 h. After standing, it was taken out, washed with deionized water and anhydrous ethanol, and dried under vacuum. The product obtained was the nickel-iron hydroxide catalyst supported on the noble metal ruthenium, denoted as RFNOH.
[0064] Using the prepared RFNOH as the cathode and FNOH as the anode, an electrolytic cell RFNOH||FNOH was assembled. The catalyst prepared in this example was subjected to instantaneous potential-time curve testing in 1 M KOH solution. The catalyst was tested at a current density of 500 mA / cm². -2 The instantaneous potential curve under the given conditions, the test results are as follows: Figure 2 As shown, the test results indicate that this catalyst operates at 500 mA / cm². 2 It maintains excellent electrochemical stability under high current density.
[0065] Matters not covered in this invention are common knowledge.
[0066] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing an electrolytic water catalyst, characterized by, The application relates to a preparation method of an electrolytic water catalyst. S1, growing transition metal hydroxide on a foamed iron substrate in situ by an etching method to prepare a precursor, comprising: adding nickel chloride and sodium chloride into deionized water and stirring uniformly, adding cleaned foamed iron as a substrate to carry out an etching reaction, taking out, cleaning with deionized water and anhydrous ethanol respectively, and drying in a vacuum environment to obtain the precursor; the cleaning method of the foamed iron is ultrasonic cleaning with anhydrous ethanol, hydrochloric acid and deionized water for 10 min respectively, and then washing with deionized water several times; S2, loading noble metal on the precursor by a solution immersion reduction method to obtain the electrolytic water catalyst, comprising: immersing the precursor in a noble metal salt aqueous solution to carry out a reduction reaction, taking out, cleaning with deionized water and ethanol respectively, and drying in a vacuum environment to obtain the electrolytic water catalyst; the noble metal salt aqueous solution is a ruthenium chloride aqueous solution.
2. The method of claim 1, wherein, The size of the foamed iron is 1 mm*20 mm*40 mm, the volume of the deionized water is 100 mL, and the amount of substance of the sodium chloride and the nickel chloride is 10 mmol and 30 mmol respectively.
3. The method of claim 1, wherein, The etching reaction temperature is normal temperature, and the reaction time is 12 h.
4. The method of claim 1, wherein, The reduction reaction temperature is normal temperature, and the reaction time is 10 h.
5. The method of claim 1, wherein, The size of the precursor is 1 cm*2 cm, the concentration of the ruthenium chloride aqueous solution is 8 mg / mL, and the volume is 2 mL.
6. The method of claim 1, wherein, The transition metal hydroxide is nickel-iron hydroxide.
7. An electrolysis water catalyst characterized by, The electrolytic water catalyst is prepared by the preparation method in any one of claims 1-6.