Preparation method and application of nickel hydroxide@mnohh / foam nickel oxygen evolution catalytic material
By preparing Ni(OH)2@MnOOH nanosheet catalysts in situ on nickel foam, the problems of high cost and insufficient catalytic performance of noble metal OER electrocatalysts were solved, achieving high efficiency and stability of OER electrocatalysis and improving the efficiency of water electrolysis.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ANHUI UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-10-23
- Publication Date
- 2026-07-31
AI Technical Summary
Existing OER electrocatalysts containing precious metals are expensive, while the catalytic performance of electrocatalysts without precious metals needs to be improved. Furthermore, the oxygen evolution reaction (OER) has slow reaction kinetics, resulting in low water electrolysis efficiency.
Ni(OH)2@MnOOH nanosheet catalytic materials were prepared in situ on nickel foam by electrodeposition. The composition and electronic properties of the electrode surface were adjusted by cyclic voltammetry, and the reaction kinetics were adjusted by thioacetamide to enhance OH- adsorption and electron transport pathways, thereby constructing highly exposed active sites.
It significantly improves the electrocatalytic activity and stability of OER, enhances the electron transport rate, reduces the material and matrix resistance, and improves the efficiency of water electrolysis and energy conversion efficiency.
Smart Images
Figure CN117431574B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of preparation methods for electrocatalytic materials, specifically relating to a preparation method and application of Ni(OH)2@MnOOH / nickel foam oxygen evolution catalytic material. Background Technology
[0002] In recent years, with the continuous development of industrialization and urbanization, human demand for energy has been rising sharply. The resulting energy and environmental problems have received increasing attention, making the development of clean energy and the reduction of environmental pollution imperative. Therefore, the search for a green, safe, and renewable new energy source has become a hot research topic for researchers both domestically and internationally. Hydrogen energy, as a zero-emission and pollution-free new energy source, has attracted widespread research and reporting. Developing abundant and efficient electrocatalytic water splitting catalysts is a prerequisite for realizing a hydrogen society. However, the water electrolysis process requires high activation energy; therefore, finding suitable catalysts is necessary to improve efficiency.
[0003] Electrocatalytic water splitting involves two half-reactions: the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Since the OER is a complex process involving four electrons, its reaction kinetics are slow, resulting in low overall efficiency of water electrolysis and requiring a high overpotential. The OER exhibits slow reaction kinetics during water electrolysis. Therefore, highly efficient electrocatalysts are crucial for reducing energy consumption and improving energy conversion efficiency in the OER. Noble metal catalysts such as rubidium, iridium, and platinum-based catalysts are currently widely considered highly efficient OER catalysts. However, the high cost and scarcity of precious metals make finding alternatives with comparable catalytic capabilities a hot research topic.
[0004] Manganese-based materials are among the most promising candidates to replace noble metal catalysts due to their abundant natural resources, low cost, and the fact that only Fe has a higher abundance than Mn among all transition metals in the Earth's crust. They also possess tunable electronic properties and excellent chemical stability. Theoretical and experimental studies have demonstrated that nanostructured manganese-based catalysts are promising OER electrocatalysts. Manganese-based oxides exhibit multiple crystal forms, and their non-stoichiometric composition and multivalent nature make them more complex than other metal oxides. Many methods exist for preparing manganese-based catalysts, with electrodeposition, as an efficient and time-saving method, showing great promise for large-scale catalyst preparation. Furthermore, electrodeposition allows for tight bonding between the catalyst and the substrate, reducing the resistance between them. In-situ electrodeposition on nickel foam not only avoids the use of binders but also improves the catalyst's conductivity and electron transfer rate. After the oxygen evolution reaction (OER), high-valence active species were detected on the electrode surface, indicating that these high-valence active species, acting as the true active phase, promote the OER. These results demonstrate that the manganese-based catalyst prepared by electrodeposition is a highly efficient and stable catalyst with significant practical application potential. Summary of the Invention
[0005] The purpose of this invention is to address the problems of high cost of existing OER electrocatalysts containing precious metals and the need to improve the catalytic performance of electrocatalysts without precious metal OERs, and to provide a method for preparing Ni(OH)2@MnOOH / foamed nickel oxygen evolution catalyst and its application.
[0006] The preparation method of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst of the present invention is carried out according to the following steps:
[0007] Step 1: The nickel foam substrate is ultrasonically cleaned sequentially with hydrochloric acid, anhydrous ethanol, and deionized water, and then dried to obtain pretreated nickel foam.
[0008] Step 2: Dissolve manganese chloride, manganese sulfate and thioacetamide in deionized water and mix well to obtain an electroplating solution. Immerse the pretreated nickel foam as the working electrode in the electroplating solution and perform electrodeposition at room temperature using cyclic voltammetry. After washing and drying, Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst material is obtained.
[0009] In step two, the electroplating solution contains manganese chloride at a concentration of 0.08–0.15 mol / L, manganese sulfate at a concentration of 0.08–0.15 mol / L, and thioacetamide at a concentration of 0.08–0.15 mol / L.
[0010] The application of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst of this invention is to use the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst as an electrode in the oxygen evolution reaction (OER) of water electrolysis.
[0011] This invention successfully constructed a Ni(OH)₂@MnOOH / nickel foam (NF) nanosheet electrocatalyst through in-situ anodic oxidation on nickel foam, which can significantly alter the electronic properties of the space charge region and promote electron transfer. This invention employs thioacetamide (TAA)-assisted electrodeposition. The TAA-induced hydrolysis process is crucial for regulating the composition of the electrode material surface. As a sulfur source, thioacetamide (TAA) can adjust the pH of the solution, thereby regulating the reaction kinetics of metal ions and sulfur ions, and consequently, the crystal phase of the metal sulfide. Furthermore, SO₄²⁻ is generated during the electrodeposition process. 2- Adsorbed SO4 2- It can be enhanced by OH - The adsorption of the material promotes the OER process. This material enhances the oxygen evolution reaction (OER) through interfacial charge transfer and redistribution in a nanoarray electrocatalyst, constructing an OER catalyst with ion and electron transport pathways, highly exposed active sites, and high reactivity. The preparation method of this invention involves electrodepositing a manganese-based catalyst onto nickel foam using cyclic voltammetry, followed by washing, drying, and storage.
[0012] Compared with existing technologies, the preparation method and application of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst of the present invention have the following advantages:
[0013] (1) The Ni(OH)2@MnOOH / foamed nickel oxygen evolution catalyst prepared by this invention is used in the field of electrocatalytic materials technology and is expected to improve energy and environmental issues.
[0014] (2) The electrocatalytic active material prepared by the present invention fully exposes the active sites and has high catalytic performance, and has a good application prospect in the field of electrocatalytic material technology.
[0015] (3) The electrocatalytic active material prepared by the present invention will increase the specific surface area, increase the active sites, promote electron transfer, and improve the electron transport rate due to its tightly packed nanosheet structure, which will promote the widespread application of transition metal compounds in other fields.
[0016] (4) Using nickel foam as the electrode substrate, the material grows directly on the nickel foam, eliminating the complicated steps of using conductive adhesive to stick it, and it is not easy to fall off, thus improving the conductivity efficiency.
[0017] The Ni(OH)2@MnOOH / foamed nickel oxygen evolution catalyst prepared by this invention has excellent OER electrocatalytic activity and long-term stability, and has broad application prospects in the field of electrocatalytic materials technology. Attached Figure Description
[0018] Figure 1 These are SEM images of the pre-processed nickel foam at different magnifications in the examples: (a) is a low-magnification SEM image, and (b) is a high-magnification SEM image.
[0019] Figure 2 These are SEM images of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst obtained in the examples at different magnifications: (a) is a low-magnification SEM image, and (b) is a high-magnification SEM image.
[0020] Figure 3 This is the Raman spectrum of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst in the examples;
[0021] Figure 4 The XRD pattern of the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst in the examples is shown.
[0022] Figure 5 These are physical images of the original nickel foam and the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst in the examples. (a) is the original nickel foam, and (b) is the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst.
[0023] Figure 6 In the examples, the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst material operates at 100 mA / cm². 2 Linear sweep volt-ampere curve at current density;
[0024] Figure 7 This is a Tafel slope diagram of the original nickel foam and Ni(OH)2@MnOOH / nickel foam, where 1 represents the Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst and 2 represents nickel foam. Detailed Implementation
[0025] Specific Implementation Method 1: The preparation method of Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst in this implementation method is carried out according to the following steps:
[0026] Step 1: The nickel foam substrate is ultrasonically cleaned sequentially with hydrochloric acid, anhydrous ethanol, and deionized water, and then dried to obtain pretreated nickel foam.
[0027] Step 2: Dissolve manganese chloride, manganese sulfate and thioacetamide in deionized water and mix well to obtain an electroplating solution. Immerse the pretreated nickel foam as the working electrode in the electroplating solution and perform electrodeposition at room temperature using cyclic voltammetry. After washing and drying, Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst material is obtained.
[0028] In step two, the electroplating solution contains manganese chloride at a concentration of 0.08–0.15 mol / L, manganese sulfate at a concentration of 0.08–0.15 mol / L, and thioacetamide at a concentration of 0.08–0.15 mol / L.
[0029] The Ni(OH)2@MnOOH / foamed nickel oxygen evolution catalyst material prepared in this embodiment exhibits superior catalytic performance in OER and excellent electrochemical performance, and has broad application prospects in the field of water electrolysis oxygen production catalyst material technology.
[0030] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the concentration of hydrochloric acid in step one is 3 mol / L, and the foamed nickel substrate is ultrasonically cleaned for 15 minutes each using hydrochloric acid, anhydrous ethanol, and deionized water in sequence.
[0031] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the drying temperature in step 1 is 60℃.
[0032] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the concentration of manganese chloride in the electroplating solution in step two is 0.1–0.12 mol / L, the concentration of manganese sulfate is 0.1–0.12 mol / L, and the concentration of thioacetamide is 0.1–0.12 mol / L.
[0033] Specific Implementation Method 5: This implementation method differs from Specific Implementation Method 4 in that the concentration of manganese chloride in the electroplating solution in step 2 is 0.1 mol / L, the concentration of manganese sulfate is 0.1 mol / L, and the concentration of thioacetamide is 0.1 mol / L.
[0034] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that in step two, manganese chloride, manganese sulfate, and thioacetamide are dissolved in deionized water and magnetically stirred for 20 minutes at room temperature until the solution is uniformly mixed.
[0035] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that cyclic voltammetry is used in step two, with Ag / AgCl as the reference electrode, Pt sheet as the counter electrode, and pretreated nickel foam as the working electrode.
[0036] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that step two uses cyclic voltammetry, the scanning potential window for electrodeposition is selected as -1.2V to 0.2V, the scanning rate is 5mV / s, and the electroplating solution undergoes 20 to 30 consecutive cycles.
[0037] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the washing in step two involves rinsing with deionized water 3 to 5 times, and the drying involves placing the item in a drying oven and drying it at 60°C for 6 hours.
[0038] Example: The preparation method of Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst in this example is carried out according to the following steps:
[0039] Step 1: Take a size of 2*2cm 2 The foamed nickel was ultrasonically cleaned for 15 min each with 3 mol / L hydrochloric acid, anhydrous ethanol and deionized water, and then dried at 60℃ for 12 h to obtain pretreated foamed nickel.
[0040] Step 2: Dissolve manganese chloride, manganese sulfate, and thioacetamide in 50 mL of deionized water and stir magnetically for 20 min at room temperature until the solution is homogeneous to obtain an electroplating solution. Immerse the pretreated nickel foam as the working electrode in the electroplating solution, select Ag / AgCl as the reference electrode and Pt sheet as the counter electrode, and perform electrodeposition using cyclic voltammetry at room temperature. The scanning potential window for electrodeposition is selected as -1.2V to 0.2V, and the scanning rate is 5mV / s. Perform 25 consecutive cyclic voltammetry cycles on the electroplating solution, then wash with deionized water and dry at 60℃ for 6 h to obtain Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst material;
[0041] In step two, the electroplating solution contains 0.1 mol / L manganese chloride, 0.1 mol / L manganese sulfate, and 0.1 mol / L thioacetamide.
[0042] The preprocessed SEM image of nickel foam in this embodiment is as follows: Figure 1 As shown, the surface of the nickel foam without a catalyst is smooth. Figure 2 This is a SEM image of the Ni(OH)2@MnOOH / nickel foam catalyst grown on the surface of nickel foam. A three-dimensional lamellar structure is clearly visible on the nickel foam surface, and it is tightly packed, forming a stark contrast to the smooth surface of the original nickel foam. The three-dimensional lamellar structure facilitates sufficient contact between the electrolyte and the catalyst, and also facilitates the removal of bubbles during the oxygen evolution reaction, thus promoting the oxygen evolution reaction. Figure 3 This is the Raman spectrum of Ni(OH)2@MnOOH / nickel foam catalyst. The Raman spectrum is at 213 cm⁻¹. -1344cm -1 and 528cm -1 There are three characteristic peaks at 450 cm⁻¹, and these peak positions correspond to the vibrational peaks of MnOOH. The spectrum shows... -1 There is a characteristic peak, corresponding to the Ni-OH vibration peak. Finally, at 970 cm⁻¹... -1 The characteristic peak at that location corresponds to SO, which also confirms that SO42- 2- exist. Figure 4 This is the XRD pattern of Ni(OH)2@MnOOH / nickel foam catalyst. The peak of elemental Ni can be seen by comparing it with the standard PDF card. Figure 5 The images show the original nickel foam and the catalyst material after electrodeposition. It can be seen that the prepared material grows relatively uniformly. The surface of the nickel foam without catalyst is smooth and silvery-white. After Ni(OH)2@MnOOH / nickel foam is grown in situ on the surface of nickel foam by electrodeposition, the surface of nickel foam is covered with a layer of black material, proving that Ni(OH)2@MnOOH / nickel foam has been successfully loaded onto the nickel foam substrate. Figure 6 The original nickel foam and Ni(OH)2@MnOOH / nickel foam catalyst were used at a current density of 100 mA / cm². 2 Linear scanning voltammetry curves were plotted at 100 mA / cm², and IR correction was performed. 2 The overpotential was 352 mV, demonstrating the electrocatalytic performance of this electrode material, which is far superior to that of the original nickel foam. Meanwhile, the Tafel slopes of the original nickel foam and the Ni(OH)₂@MnOOH / nickel foam electrode material were 185 mV / dec and 134 mV / dec, respectively (e.g., ...). Figure 7 As shown, the Tafel slope of the electrode material is much smaller than that of the original nickel foam material, indicating that Ni(OH)2@MnOOH / nickel foam has a faster electron transfer rate.
Claims
1. A preparation method of a nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material, characterized in that The preparation method is carried out according to the following steps: Step 1: The nickel foam substrate is ultrasonically cleaned sequentially with hydrochloric acid, anhydrous ethanol, and deionized water, and then dried to obtain pretreated nickel foam. Step 2: Dissolve manganese chloride, manganese sulfate, and thioacetamide in deionized water and mix thoroughly to obtain an electroplating solution. Immerse the pretreated nickel foam as the working electrode in the electroplating solution and perform electrodeposition at room temperature using cyclic voltammetry. Control the scanning potential window for electrodeposition to be -1.2V to 0.2V, and the scanning rate to be 5mV / s. Perform 20 to 30 consecutive cyclic voltammetry cycles on the electroplating solution. After washing and drying, obtain Ni(OH)2@MnOOH / nickel foam oxygen evolution catalyst material. In step two, the electroplating solution contains manganese chloride at a concentration of 0.08–0.15 mol / L, manganese sulfate at a concentration of 0.08–0.15 mol / L, and thioacetamide at a concentration of 0.08–0.15 mol / L. 2.The preparation method of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 1, characterized in that The hydrochloric acid concentration mentioned in step one is 3 mol / L. The nickel foam substrate is ultrasonically cleaned for 15 min each using hydrochloric acid, anhydrous ethanol, and deionized water in sequence.
3. The preparation method of the nickel hydroxide@MnOOH / nickel foam oxygen evolution catalyst according to claim 1, characterized in that... The drying temperature in step one is 60℃. 4.The preparation method of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 1, characterized in that In step two, the concentrations of manganese chloride, manganese sulfate, and thioacetamide in the electroplating solution are 0.1–0.12 mol / L.
5. The preparation method of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 4, characterized in that In step two, the concentrations of manganese chloride, manganese sulfate, and thioacetamide in the electroplating solution are 0.1 mol / L, 0.1 mol / L, and 0.1 mol / L, respectively. 6.The preparation method of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 1, characterized in that In step two, manganese chloride, manganese sulfate, and thioacetamide are dissolved in deionized water and magnetically stirred for 20 minutes at room temperature until the solution is homogeneous.
7. The preparation method of the nickel hydroxide@MnOOH / nickel foam oxygen evolution catalyst according to claim 1, characterized in that... In step two, cyclic voltammetry is used, with Ag / AgCl as the reference electrode, Pt sheet as the counter electrode, and pretreated nickel foam as the working electrode. 8.The preparation method of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 1, characterized in that In step two, washing involves rinsing with deionized water 3-5 times, and drying involves placing the item in a drying oven at 60°C for 6 hours.
9. The nickel hydroxide@MnOOH / nickel foam oxygen evolution catalyst material prepared by the preparation method according to any one of claims 1-8.
10. The use of the nickel hydroxide@MnOOH / foam nickel oxygen evolution catalytic material according to claim 9, characterized in that The nickel hydroxide@MnOOH / foam nickel oxygen evolution catalyst material was used as an electrode in the water electrolysis catalytic reaction for the oxygen evolution reaction.