Preparation method of catalyst, catalyst, electrode and application of electrode
By ultrasonic cleaning and sandpaper grinding of the iron sheet substrate, and growing the catalytic layer in the nickel and magnesium metal salt precursor solution to form a +2valent cation defect structure, the problem of poor activity and low stability of the iron-based catalyst is solved, and efficient, stable and low-cost catalyst preparation is achieved.
Patent Information
- Application Number
- CN202510298407.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-05-13
AI Technical Summary
The existing iron-based catalysts have problems such as poor catalytic activity, low stability, complex preparation process and weak substrate binding force, which limits their application in electrolytic hydrogen production.
The iron sheet substrate was cleaned by cutting and ultrasonic, and the surface roughness was increased by sandpaper grinding. Then the catalytic layer was grown in the nickel and magnesium metal salt precursor solution, and then a +2V cation defect structure was formed by alkali treatment to prepare a catalyst with high catalytic activity and stability.
The catalyst preparation is achieved at low cost under normal temperature and pressure, which improves catalytic activity and stability, reduces energy consumption and preparation costs, and has strong bonding force between the catalytic layer and the substrate, avoiding falling off.
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Figure CN119980298A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrolytic hydrogen production catalysts, and in particular to a catalyst preparation method, a catalyst, an electrode and applications thereof. Background Art
[0002] At present, the precious metal catalysts (such as ruthenium-based and iridium-based catalysts) widely used in water electrolysis hydrogen production technology have excellent catalytic activity and stability, but their high cost and low crustal abundance seriously restrict their industrial application. Although non-precious metal iron-based catalysts are low-cost, they have the following technical defects:
[0003] First, the catalytic activity of iron-based catalysts is poor, and a large overpotential is required to promote the occurrence of the oxygen evolution reaction, which will lead to high energy consumption in hydrogen production by electrolysis.
[0004] Second, iron-based catalysts are easily deactivated under strong oxidizing and alkaline corrosive conditions, making it difficult to achieve long-term stable catalysis.
[0005] Third, during the preparation process, iron-based catalysts usually require relatively harsh external conditions such as high temperature, which will result in higher preparation costs and difficulty in industrial scale-up.
[0006] Fourth, the bonding force between the substrate and the catalytic layer of the iron-based catalyst is poor, and it is easy to fall off. Summary of the invention
[0007] In order to at least partially solve the problems of poor activity, stability, complex preparation process and weak substrate binding force existing in iron-based catalysts in the related art, the present invention provides a method for preparing a catalyst, a catalyst, an electrode and applications thereof.
[0008] In order to achieve the above object, the technical solution adopted by the present invention includes:
[0009] According to a first aspect of the present invention, there is provided a method for preparing a catalyst, comprising the following steps:
[0010] Step S1: cutting the iron sheet substrate and performing ultrasonic cleaning on it;
[0011] Step S2: grinding the surface of the iron sheet substrate with sandpaper to increase its roughness;
[0012] Step S3: preparing a precursor solution containing nickel and magnesium metal salts;
[0013] Step S4: immersing the iron sheet substrate obtained in step S2 into the nickel and magnesium metal salt precursor solution obtained in step S3 to grow a catalytic layer;
[0014] Step S5: treating the material obtained in step S4 with an alkali to completely remove the magnesium ions, thereby forming a +2-valent cation defect structure;
[0015] Step S6: Wash and dry the material obtained in step S5 to obtain the target catalyst.
[0016] Optionally, in step S2, the mesh number N of the sandpaper satisfies: 100 mesh ≤ N ≤ 300 mesh.
[0017] Optionally, the length L, width W and thickness H of the base iron sheet respectively satisfy: 3cm≤L≤10cm, 0.5cm≤W≤10cm, 0.1mm≤H≤0.5mm.
[0018] Optionally, step S3 includes: dissolving nickel sulfate hexahydrate and anhydrous magnesium sulfate in deionized water to obtain a NiFe(Mg)-LDH precursor solution.
[0019] The magnesium ion concentration in the NiFe(Mg)-LDH precursor solution is 0.25×10 -4 mol / L to 2.5×10 - 3 mol / L, nickel ion is 0.5×10 -4 mol / L to 5×10 -3 mol / L;
[0020] Alternatively, the ratio of magnesium ions to nickel ions in the NiFe(Mg)-LDH precursor solution is 1:20 to 1:2.
[0021] Optionally, the step S5 specifically includes: transferring the material obtained in step S4 to a KOH solution with a concentration of 6 mol / L until all magnesium ions are released to form a +2-valent cation defect structure.
[0022] According to the second aspect of the present invention, a catalyst is also provided, which is prepared by the catalyst preparation method described in any technical solution in the first aspect of the present invention, and the catalyst includes an iron sheet substrate, a catalytic layer attached to the iron sheet substrate, and a +2-valent cation defect structure.
[0023] Optionally, in an electrolyte of 1 mol / L KOH,
[0024] At 10mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 224 mV;
[0025] At 100mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 282 mV;
[0026] At 0.3A / cm 2 Under the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 344mV.
[0027] According to a third aspect of the present invention, an electrode is further provided, wherein the electrode comprises the catalyst described in any one of the technical solutions in the second aspect of the present invention.
[0028] According to the fourth aspect of the present invention, there is also provided the use of a catalyst prepared by the method for preparing the catalyst described in any one of the technical solutions in the first aspect of the present invention, or the catalyst described in any one of the technical solutions in the second aspect of the present invention, or the electrode described in the third aspect of the present invention in hydrogen production by electrolysis. The catalyst prepared by the method for preparing the catalyst, or the catalyst, or the electrode is at least used to promote water decomposition reaction in hydrogen production by electrolysis.
[0029] Beneficial effects:
[0030] 1. Through the above technical scheme, first, the present invention adopts low-cost, industrially mature iron sheets as the substrate, and by ultrasonically cleaning and sandpaper polishing the surface of the cut iron sheet substrate, the surface roughness of the iron sheet substrate can be improved, thereby enhancing the bonding force between the catalyst layer and the iron sheet substrate and reducing the possibility of the catalyst layer falling off.
[0031] Second, the catalyst of the present invention can be prepared under normal temperature and pressure conditions, without the need for harsh external conditions such as high temperature. The synthesis method is simple, the preparation cost is low, it is easy to scale up industrially, and no additional energy consumption is required during the preparation process.
[0032] Third, by constructing +2-valent cation defects, the present invention can enhance the intrinsic catalytic activity of the active sites adjacent to the defects, thereby enhancing the catalytic activity of the catalyst, so that it does not require an excessively large overpotential to promote the occurrence of the oxygen evolution reaction (that is, it can promote the occurrence of the oxygen evolution reaction at a smaller overpotential), especially the catalytic performance is excellent under high current density conditions.
[0033] Fourthly, the catalyst of the present invention exhibits excellent stability during the catalytic process and can achieve long-term stable catalysis.
[0034] 2. Other beneficial effects or advantages of the present invention will be described in detail in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative labor.
[0036] in:
[0037] Figure 1 is a schematic flow chart of steps of a method for preparing a catalyst provided by an exemplary embodiment of the present invention;
[0038] Figure 2 Schematic diagram of the LSV activity comparison of iron-based catalysts prepared by different precursor solutions (Ni Fe (Mg) -LDH solution, NiFe -LDH solution, Ni Fe (Al) -LDH solution), wherein Current density refers to current density, Potent ia l (V vs RHE) refers to the voltage value based on the reversible hydrogen electrode (RHE);
[0039] Figure 3 An exemplary embodiment of the present invention provides a catalyst at 10 mA / cm 2 Schematic diagram of the 100-h catalytic stability test results at a current density of , wherein Potent ia l (V vs RHE) represents the voltage value based on the reversible hydrogen electrode (RHE);
[0040] Figure 4 An exemplary embodiment of the present invention provides a catalyst at 0.1A / cm 2 Schematic diagram of the 100-h catalytic stability test results at a current density of , wherein Potent ia l (V vs RHE) represents the voltage value based on the reversible hydrogen electrode (RHE). DETAILED DESCRIPTION
[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in 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.
[0042] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.
[0043] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.
[0044] Example 1
[0045] like Figure 1 As shown, according to the first aspect of the present invention, this embodiment provides a method for preparing a catalyst, comprising the following steps:
[0046] Step S1: cutting the iron sheet substrate and performing ultrasonic cleaning on it;
[0047] Step S2: grinding the surface of the iron sheet substrate with sandpaper to increase its roughness;
[0048] Step S3: preparing a precursor solution containing nickel and magnesium metal salts;
[0049] Step S4: immersing the iron sheet substrate obtained in step S2 into the nickel and magnesium metal salt precursor solution obtained in step S3 to grow a catalytic layer;
[0050] Step S5: treating the material obtained in step S4 with an alkali to completely remove the magnesium ions, thereby forming a +2-valent cation defect structure;
[0051] Step S6: Wash and dry the material obtained in step S5 to obtain the target catalyst.
[0052] Through the above technical scheme, firstly, the present invention adopts low-cost and highly industrially mature iron sheets as the substrate, and by ultrasonically cleaning and sandpaper polishing the surface of the cut iron sheet substrate, the surface roughness of the iron sheet substrate can be improved, thereby enhancing the bonding force between the catalyst layer and the iron sheet substrate and reducing the possibility of the catalyst layer falling off.
[0053] Second, the catalyst of the present invention can be prepared under normal temperature and pressure conditions, the synthesis method is simple, the preparation cost is low, and no harsh external conditions such as high temperature are required. The catalytic layer can be optimized through solution impregnation and alkali treatment, which is easy to scale up industrially and does not require additional energy consumption during the preparation process.
[0054] Third, by constructing +2-valent cation defects, the present invention can enhance the intrinsic catalytic activity of the active sites adjacent to the defects, thereby enhancing the catalytic activity of the catalyst, so that it does not require an excessively large overpotential to promote the occurrence of the oxygen evolution reaction (that is, it can promote the occurrence of the oxygen evolution reaction at a smaller overpotential), especially the catalytic performance is excellent under high current density conditions.
[0055] Fourthly, the catalyst of the present invention exhibits excellent stability during the catalytic process and can achieve long-term stable catalysis.
[0056] To facilitate understanding by relevant technical personnel, the present invention is described below in conjunction with an exemplary implementation.
[0057] Step 1: Cut the base iron sheet, the length L, width W and thickness H of the base iron sheet can respectively meet the following conditions: 3cm≤L≤10cm, 0.5cm≤W≤10cm, 0.1mm≤H≤0.5mm. Place the cut iron sheet in anhydrous ethanol and perform ultrasonic treatment for 2 to 4 minutes.
[0058] Step 2: Use sandpaper (it can be understood that the mesh number of the sandpaper can be selected from 100 mesh to 300 mesh) to grind the surface of the cut iron sheet to increase the roughness of the surface of the iron sheet.
[0059] Step 3: Prepare different precursor solutions for catalytic performance comparison.
[0060] 1) Preparation of NiFe(Mg)-LDH precursor solution: 0.0263 g of nickel sulfate hexahydrate and 0.0012 g of anhydrous magnesium sulfate were weighed on an analytical balance and dissolved in 100 mL of deionized water to obtain a transparent clear solution.
[0061] 2) Preparation of NiFe-LDH precursor solution: 0.0263 g of nickel sulfate hexahydrate was weighed using an analytical balance and dissolved in 100 mL of deionized water to obtain a transparent clear solution.
[0062] 3) Preparation of NiFe(Al)-LDH precursor solution: Use an analytical balance to weigh 0.0263 g of nickel sulfate hexahydrate and 0.0037 g of aluminum nitrate nonahydrate, respectively, and dissolve them in 100 mL of deionized water to obtain a transparent clear solution.
[0063] Step 4: Completely immerse the polished iron sheet in different precursor solutions, and take it out after a uniform catalytic layer grows on the surface.
[0064] Step 5: Transfer the NiFe(Mg)-LDH and Ni Fe(Al)-LDH materials into a KOH solution with a concentration of 6 mol / L until the magnesium ions and aluminum ions are completely released, so as to construct corresponding cation defects respectively.
[0065] Step 6: Take out the above materials respectively, rinse them repeatedly with deionized water and anhydrous ethanol, and vacuum dry them for 8h-12h to obtain the target catalyst.
[0066] In this embodiment, the catalytic activity test method of the oxygen evolution reaction at the anode of electrolyzed water is: an electrochemical test is performed using an electrochemical workstation (CH I760F), a three-electrode test system is used, the working electrode is the electrode of the present invention, the counter electrode is a Pt wire, and the reference electrode is a mercury oxide electrode. The electrolyte is a potassium hydroxide solution with a concentration of 1 mol / L, and the test temperature is room temperature 25°C. The LSV test curve is a scan rate of 5 mV / s, and the voltage is the voltage of the corresponding reversible hydrogen electrode.
[0067] In this embodiment, the electrode is prepared by cutting the obtained electrode, and its active area is actually tested to be 0.2 cm×0.2 cm. A length of 3 cm is reserved above the electrode for connecting to an electrochemical workstation, and the remaining area is completely covered with hot melt adhesive to be suitable for promoting water decomposition reaction in electrolytic hydrogen production.
[0068] In this embodiment, the electrochemical test results are as follows: Figure 2 As shown. Figure 2 It can be seen that
[0069] For the NiFe(Mg)-LDH catalyst, at 10 mA / cm 2 At a current density of 100 mA / cm, the overpotential is 224 mV (that is, it can significantly reduce energy consumption); at a current density of 100 mA / cm 2 At a current density of 0.3A / cm, the overpotential is 282mV; at 0.3A / cm 2 At a current density of , the overpotential is 344 mV.
[0070] For the NiFe-LDH catalyst, at 10 mA / cm 2 At a current density of 100 mA / cm, the overpotential is 221 mV; at a current density of 100 mA / cm 2 At a current density of , the overpotential is 304mV.
[0071] For the catalyst of NiFe(Al)-LDH material, the overpotential is 266 mV at a current density of 10 mA / cm2; 2 At a current density of , the overpotential is 346 mV.
[0072] It can be seen that the catalyst of Ni Fe(Mg)-LDH material exhibits excellent OER catalytic activity at high current density, indicating that the presence of +2-valent metal cation defects can effectively improve the catalytic activity.
[0073] Also, see Figure 3 and Figure 4 The catalytic stability of the NiFe(Mg)-LDH catalyst of the present invention was tested. 2 At a current density of 0.1A / cm 2 The material can also be stably tested for 100h at a current density of .
[0074] In one embodiment of the present invention, the magnesium ion concentration in the NiFe(Mg)-LDH precursor solution may be 0.25×10 -4 mol / L to 2.5×10 -3 mol / L, nickel ions can be 0.5×10 -4 mol / L to 5×10 -3 mol / L; or, in another embodiment of the present invention, the ratio of magnesium ions to nickel ions in the NiFe(Mg)-LDH precursor solution may be 1:20 to 1:2.
[0075] According to the second aspect of the present invention, a catalyst is also provided, which is prepared by the catalyst preparation method of any technical solution in the first aspect of the present invention, and the catalyst includes an iron sheet substrate, a catalytic layer attached to the iron sheet substrate, and a +2-valent cation defect structure.
[0076] In this embodiment, it is understood that the catalyst of the present invention includes an iron sheet substrate, a catalyst layer attached to the iron sheet substrate, and vacancy defects formed by the release of magnesium ions. In this way, the catalyst prepared in this way is not only low in preparation cost and easy to industrially scale up, but also has a strong bonding force between the catalyst layer and the iron sheet substrate and is not easy to fall off. In addition, the catalytic activity and stability of the catalyst can be effectively improved.
[0077] In one embodiment of the present invention, in the electrolyte of 1 mol / L KOH,
[0078] At 10mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 224 mV;
[0079] At 100mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 282 mV;
[0080] At 0.3A / cm 2 Under the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 344mV.
[0081] According to the third aspect of the present invention, there is also provided an electrode, wherein the electrode comprises the catalyst of any one of the technical solutions in the second aspect of the present invention.
[0082] In this embodiment, the electrode of the present invention can be integrated into an anion exchange membrane electrolyzer for use in a large-scale hydrogen production system to reduce the reliance on precious metals and improve energy efficiency. At the same time, the electrode of the present invention is not only low in preparation cost and easy to scale up industrially, but also has a strong bonding force between the catalyst layer and the iron sheet substrate and is not easy to fall off. In addition, it can also effectively improve the catalytic activity and stability of the catalyst.
[0083] According to the fourth aspect of the present invention, there is also provided a catalyst prepared by the method for preparing the catalyst according to any one of the technical solutions in the first aspect of the present invention, or a catalyst according to any one of the technical solutions in the second aspect of the present invention, or an electrode according to the third aspect of the present invention for use in hydrogen production by electrolysis. The catalyst prepared by the method for preparing the catalyst, or the catalyst, or the electrode is at least used to promote the water decomposition reaction in hydrogen production by electrolysis.
[0084] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A method for preparing a catalyst, characterized in that: The steps include: Step S1: cutting the iron sheet substrate and performing ultrasonic cleaning on it; Step S2: grinding the surface of the iron sheet substrate with sandpaper to increase its roughness; Step S3: preparing a precursor solution containing nickel and magnesium metal salts; Step S4: immersing the iron sheet substrate obtained in step S2 into the nickel and magnesium metal salt precursor solution obtained in step S3 to grow a catalytic layer; Step S5: treating the material obtained in step S4 with an alkali to completely remove the magnesium ions, thereby forming a +2-valent cation defect structure; Step S6: Wash and dry the material obtained in step S5 to obtain the target catalyst.
2. The method for preparing a catalyst according to claim 1, characterized in that: In the step S2, the mesh number N of the sandpaper satisfies: 100 mesh ≤ N ≤ 300 mesh.
3. The method for preparing the catalyst according to claim 1, characterized in that: The length L, width W and thickness H of the base iron sheet respectively satisfy the following: 3cm≤L≤10cm, 0.5cm≤W≤10cm, 0.1mm≤H≤0.5mm.
4. The method for preparing the catalyst according to claim 1, characterized in that: The step S3 comprises: dissolving nickel sulfate hexahydrate and anhydrous magnesium sulfate in deionized water to obtain a NiFe(Mg)-LDH precursor solution.
5. The method for preparing the catalyst according to claim 4, characterized in that: The magnesium ion concentration in the NiFe(Mg)-LDH precursor solution is 0.25×10 -4 mol / L to 2.5×10 -3 mol / L, nickel ion is 0.5×10 -4 mol / L to 5×10 -3 mol / L; Alternatively, the ratio of magnesium ions to nickel ions in the NiFe(Mg)-LDH precursor solution is 1:20 to 1:
2.
6. The method for preparing a catalyst according to claim 1, characterized in that: The step S5 specifically includes: transferring the material obtained in step S4 into a KOH solution with a concentration of 6 mol / L until all magnesium ions are released to form a +2-valent cation defect structure.
7. A catalyst, characterized in that The catalyst is prepared by the preparation method of the catalyst described in any one of claims 1 to 6, wherein the catalyst comprises an iron sheet substrate, a catalytic layer attached to the iron sheet substrate, and a +2-valent cation defect structure.
8. The catalyst according to claim 7, characterized in that In 1 mol / L KOH electrolyte, At 10mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 224 mV; At 100mA / cm 2 At the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 282 mV; At 0.3A / cm 2 Under the current density, the overpotential of the oxygen evolution reaction of the catalyst is less than or equal to 344mV.
9. An electrode, characterized in that: The electrode comprises the catalyst according to claim 7 or 8.
10. Use of the catalyst prepared by the method for preparing the catalyst according to any one of claims 1 to 6, or the catalyst according to claim 7 or 8, or the electrode according to claim 9 in electrolytic hydrogen production, characterized in that: The catalyst prepared by the catalyst preparation method, or the catalyst, or the electrode is at least used to promote water decomposition reaction in hydrogen production by electrolysis.