Method for the pulse electrodeposition of electrode materials and its use in the oxygen evolution reaction
Nickel-cobalt-selenium electrode materials were prepared by pulse electrodeposition and electrochemical activation treatment, which solved the problems of harsh preparation conditions and high cost in the existing technology, and achieved efficient and stable oxygen evolution reaction performance in water electrolysis, while reducing the amount of precious metals used.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2025-05-23
- Publication Date
- 2026-07-21
AI Technical Summary
In the existing technology, the methods for preparing nickel cobalt selenide electrode materials have problems such as harsh preparation conditions, high cost and poor material stability. In addition, the high cost and scarcity of precious metal catalysts limit the application of oxygen evolution reaction in water electrolysis.
A method combining pulsed electrodeposition and electrochemical activation was adopted to form porous metal oxides by co-deposition in a nickel-cobalt-selenium precursor solution. Oxygen vacancies were formed by the shedding and reconstruction of the selenium phase, which optimized the electronic structure and active sites and reduced the OER overpotential.
It achieves effective regulation of oxygen vacancies, significantly improves the catalytic performance and stability of electrode materials, reduces production costs, is suitable for large-scale production, and is applicable to the oxygen evolution reaction of water electrolysis.
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Figure CN120485847B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical catalytic material preparation technology, specifically to a method for preparing electrode materials by pulse electrodeposition, and the application of the electrode material in the oxygen evolution reaction. Background Technology
[0002] Electrolysis of water for hydrogen production has attracted widespread attention as an efficient and environmentally friendly method. The oxygen evolution reaction (OER) in water electrolysis is a crucial half-reaction in this process. Noble metal-based catalysts (such as IrO2 and RuO2) are commonly used catalysts for the OER reaction, but their high cost and scarcity limit their large-scale application. Therefore, developing low-cost, efficient, and stable non-noble metal-based OER catalysts is of great significance.
[0003] Current research shows that the OER reaction is still limited by slow kinetics, requiring highly efficient electrocatalysts to reduce overpotential and improve reaction efficiency. The OER reaction mainly involves two reaction mechanisms: Adsorbate Evolution (AEM) and Lattice Oxygen-Mediated (LOM): i) The AEM mechanism involves the adsorption and desorption of intermediates (OH-). ads →O ads →OOH ads →O 2ads In this mechanism, the adsorption energies of OER intermediates (*OH and *OOH) at the metal active sites exhibit a linear relationship (ΔG). OOH =ΔG OH (+3.2±0.2 eV), theoretically the overpotential is approximately 370 mV. ii) The LOM mechanism relies on lattice oxygen mediation, where lattice oxygen atoms in the catalyst directly participate in O−O coupling, which facilitates breaking the linear relationship and reducing the theoretical overpotential. The LOM mechanism is more likely to occur in amorphous metal oxides with a large number of oxygen vacancies and in inclusion crystals with high metal-oxygen ligand covalentity. This mechanism relies on lattice oxygen mediation. Oxygen vacancy defects (OV) are widely present in metal oxides and affect the local geometry and electronic structure of the material, generating unsaturated coordination sites, thereby forming a large number of catalytic active sites. OV can also promote the adsorption and conversion of intermediates, effectively regulate the electronic structure, inhibit competitive reactions, and thus improve the overall catalytic performance.
[0004] Ni exists in nickel-cobalt compounds 2+ / Ni 3+ and Co 2+ / Co 3+ Two redox couples effectively promote the adsorption and transformation of reaction intermediates, lowering the reaction energy barrier and thus enhancing OER activity. Meanwhile, nickel-cobalt compounds are highly tunable and easily doped with other elements to improve catalytic performance. Selenium ions (Se...)2- The oxidation potential of oxygen (0.74 V vs. SHE) is lower than that of oxygen (O₂). 2- The oxidation potential of Se is 0.40 V (v vs. SHE). During the electrochemical activation process, Se... 2- More easily oxidized to Se 4+ The selenide dissolves and detaches from the electrode surface, providing active sites for the formation of oxygen vacancies. Furthermore, selenides possess in-situ reconstruction capabilities, driving surface reconstruction of metal oxides (such as NiO and Co3O4) through the shedding of selenium phase materials, thus exposing more active sites. Therefore, the preparation of electrode materials using nickel-cobalt-selenium metal has become a new research direction. However, existing preparation methods typically employ hydrothermal, co-precipitation, high-temperature pyrolysis, and constant-current electrodeposition methods, which suffer from stringent preparation conditions, high costs, and poor material stability.
[0005] Therefore, this invention aims to propose a new technical solution to solve the above problems. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing electrode materials by pulse electrodeposition and its application in the oxygen evolution reaction.
[0007] To solve the technical problem, the solution of the present invention is:
[0008] A method for preparing electrode materials by pulse electrodeposition is provided, comprising:
[0009] (1) Dissolve the transition metal salt and selenium source in deionized water and stir until homogeneous to obtain a precursor solution;
[0010] (2) Using nickel foam as the working electrode and platinum sheet as the counter electrode, the precursor solution was added to the electrolytic cell to build a dual-electrode electrolytic system; the transition metal ions and selenium ions were co-deposited on the working electrode by pulse electrodeposition, and a catalyst layer containing transition metals and selenides was formed on the surface of the working electrode.
[0011] (3) After cleaning the working electrode, immerse it in an alkaline solution along with the graphite counter electrode and the Hg / HgO reference electrode to build an electrochemical system. The working electrode is electrochemically activated by cyclic voltammetry to induce the selenium phase in the catalyst layer of the working electrode to detach. The surface of the catalyst layer is reconstructed to form a porous metal oxide, thus obtaining the electrode material for the oxygen evolution reaction of water electrolysis.
[0012] In a preferred embodiment of the present invention, the transition metal is one or more of nickel, cobalt, iron or copper, and the transition metal salt is a nitrate, chloride or acetate.
[0013] As a preferred embodiment of the present invention, the selenium source is selenium dioxide.
[0014] As a preferred embodiment of the present invention, in the precursor solution, the molar ratio of each transition metal ion to selenium ion is 1:1.
[0015] As a preferred embodiment of the present invention, in step (2), before using the nickel foam, the nickel foam is ultrasonically cleaned with acetone, ethanol and deionized water for 10 to 30 minutes respectively, and then dried at 60°C for 30 to 60 minutes.
[0016] As a preferred embodiment of the present invention, the alkaline solution is a KOH solution with a concentration of 1M.
[0017] As a preferred embodiment of the present invention, when performing co-deposition using pulsed electrodeposition, the control parameters are: pulse current density 30 mA / cm². 2 The pulse width is 2s, the pulse interval is 0.4 to 10s, and the total deposition time is 360 to 1800s.
[0018] As a preferred embodiment of the present invention, when performing electrochemical activation treatment by cyclic voltammetry, the control parameters are: scan rate 50 mV / s, scan range 0.3~1 V vs. Hg / HgO, and number of cycles 50.
[0019] The present invention further provides the application of the electrode material prepared by the aforementioned method in the oxygen evolution reaction of water electrolysis.
[0020] Brief description of the invention principle:
[0021] The innovative design of this invention lies in proposing an in-situ self-reconstruction method for preparing transition metal selenide electrode materials. By utilizing the shedding of selenides during the activation process to provide a larger specific surface area and expose more active sites, the catalytic performance and stability are significantly improved. This invention employs selenides to construct oxygen vacancies, and through pulsed electrodeposition combined with electrochemical activation treatment, abundant oxygen vacancies are induced in the surface lattice of metal oxides (such as NiO and Co3O4) during selenium phase shedding. The presence of oxygen vacancies lowers the oxygen adsorption energy barrier on the material surface, optimizes the electron transport path, and thus significantly reduces the OER overpotential and improves stability. This solves the problem of insufficient controllability of oxygen vacancies in traditional methods, providing a dual optimization mechanism for improving catalytic performance.
[0022] This invention utilizes the mild conditions and highly controllable parameters of pulsed electrodeposition technology. By adjusting pulse parameters (such as pulse width, interval time, and current density), the microstructure and surface chemical state of the material can be precisely controlled, achieving directional regulation of oxygen vacancy density and distribution. Compared with traditional preparation methods (such as hydrothermal methods) and constant current / piezoelectric deposition methods, this invention can better control reaction conditions, more precisely regulate the distribution of defects and highly efficient active sites, and reduce preparation costs.
[0023] Compared with the prior art, the beneficial effects of the present invention are:
[0024] 1. This invention enables effective regulation of oxygen vacancies: by inducing abundant oxygen vacancies on the surface of metal oxides during electrochemical activation, the electronic structure is optimized and rich active sites are provided, thereby accelerating the OER reaction kinetics. XPS analysis confirms that the binding energy between the nickel phase and cobalt is reduced after electrochemical activation treatment. Figures 3-4 Selenium phase material disappears ( Figure 5 ), and the oxygen content decreased ( Figure 6 This indicates that a large number of oxygen vacancies are formed after electrochemical activation, which is directly related to the improvement of catalytic performance.
[0025] 2. This invention improves the performance of the oxygen evolution reaction (OER): through pulsed electrodeposition combined with electrochemical activation, in-situ self-reconstruction is achieved, enhancing electrode stability. The shedding of the selenium phase forms a porous metal oxide structure (such as NiO or Co3O4), significantly increasing the specific surface area, exposing more active sites, and enhancing catalytic activity, which is superior to traditional transition metal selenides and unactivated comparative materials. Simultaneously, the catalyst achieves self-optimization during the OER process through dynamic selenium phase shedding and oxygen vacancy generation, further extending its service life and meeting the long-term operational requirements of industrial electrolyzers.
[0026] 3. This invention can reduce the use of precious metals and lower production costs: By using non-precious metal raw materials (Ni, Co, Se), the cost is reduced by more than 80% compared to precious metal catalysts (such as IrO2, RuO2). By adjusting the types of transition metal salts (such as nickel, cobalt, iron, copper) and the precursor ratio, composite catalysts with different compositions can be flexibly designed to meet diverse needs for hydrogen production through water electrolysis.
[0027] 4. The method of this invention is simple to operate, with highly controllable parameters (pulse current density, width, interval, etc.), requiring no high-temperature or high-pressure equipment, making it suitable for large-scale production. The prepared electrode material, when applied in an electrolytic cell, exhibits excellent electrocatalytic oxygen evolution performance. Attached Figure Description
[0028] Figure 1 In the middle (a) and (b), respectively, are scanning electron microscope (SEM) images of the catalyst layers prepared in Comparative Example 1 and Example 1 of the present invention.
[0029] Figure 2 The X-ray diffraction (XRD) patterns are those of the catalysts prepared in Example 1 and Comparative Example 1 of this invention.
[0030] Figure 3 These are the electron paramagnetic resonance (EPR) maps of the catalysts prepared in Example 1 and Comparative Example 1.
[0031] Figure 4This is a partial peak diagram of Co 2p from the X-ray photoelectron spectroscopy (XPS) of the catalysts prepared in Example 1 and Comparative Example 1.
[0032] Figure 5 This is a Ni 2p peak pattern of the X-ray photoelectron spectroscopy (XPS) of the catalysts prepared in Example 1 and Comparative Example 1.
[0033] Figure 6 This is a peak diagram of Se 3d from the X-ray photoelectron spectroscopy (XPS) of the catalysts prepared in Example 1 and Comparative Example 1.
[0034] Figure 7 This is the O 1s peak diagram of the X-ray photoelectron spectroscopy (XPS) of the catalysts prepared in Example 1 and Comparative Example 1.
[0035] Figure 8 This is the full spectrum of the X-ray photoelectron spectroscopy (XPS) of the catalysts prepared in Example 1 and Comparative Example 1.
[0036] Figure 9 The polarization curves of the catalysts prepared in Examples 1-3 and Comparative Example 2 of this invention in 1M KOH are shown.
[0037] Figure 10 The graph shows the IT stability test results of the catalyst prepared in Example 1 of this invention in 1M KOH for 24 h. Detailed Implementation
[0038] The present invention will now be described in detail with reference to specific embodiments.
[0039] Part One: Examples and Comparative Cases
[0040] Example 1
[0041] NiCoSe prepared using nickel foam (NF) as a substrate x / NF electrode materials
[0042] Cut the nickel foam into 1 cm × 2 cm pieces, and ultrasonically clean them with acetone, ethanol and deionized water for 10 min each, then dry them at 60℃ for 30 min before use.
[0043] NiCl₂·6H₂O, Co(NO₃)₂·6H₂O, and SeO₂ were dissolved in 50 mL of deionized water at a molar ratio of 1:1:1 and stirred until homogeneous to obtain a precursor solution, which was then poured into an electrolytic cell. A dual-electrode system was constructed using nickel foam as the working electrode and a platinum sheet as the counter electrode for pulse electrodeposition. The pulse current density was controlled at 30 mA / cm². 2The pulse width was 2s, the pulse interval was 2s, the pulses were 150 times (2s / pulse), and the total deposition time was 600s.
[0044] The working electrode was removed and cleaned thoroughly. It was then used as the working electrode, with a graphite rod as the counter electrode and Hg / HgO as the reference electrode, and immersed in a 1M KOH solution to construct an electrochemical system. The working electrode was activated using cyclic voltammetry. The scan rate was controlled at 50 mV / s, the scan range was 0.3–1 V vs. Hg / HgO, and the number of cycles was 50.
[0045] Remove the working electrode, clean it thoroughly, and you have NiCoSe. x / NF electrode material.
[0046] This electrode material can be directly used in the oxygen evolution reaction of water electrolysis. Specifically, it is used as the anode in the oxygen evolution reaction (OER).
[0047] Example 2
[0048] The procedure was carried out according to Example 1, except that the pulse electrodeposition parameters were controlled as follows: pulse current density 30 mA / cm². 2 The pulse width is 2s, the pulse interval is 10s, and the total deposition time is 1800s.
[0049] Example 3
[0050] The procedure was carried out according to Example 1, except that the pulse electrodeposition parameters were controlled as follows: pulse current density 30 mA / cm². 2 The pulse width is 2s, the pulse interval is 0.4s, and the total deposition time is 360s.
[0051] Example 4
[0052] NiFeSe prepared using nickel foam (NF) as a substrate x / NF electrode materials
[0053] Cut the nickel foam into 1 cm × 2 cm pieces, and ultrasonically clean them with acetone, ethanol and deionized water for 20 min each, then dry them at 60℃ for 40 min before use.
[0054] NiCl₂·6H₂O, Fe(NO₃)₃·9H₂O, and SeO₂ were dissolved in 50 mL of deionized water at a molar ratio of 1:1:1 and stirred until homogeneous to obtain a precursor solution, which was then poured into an electrolytic cell. A dual-electrode system was constructed using nickel foam as the working electrode and a platinum sheet as the counter electrode for pulsed electrodeposition. The pulsed current density was controlled at 30 mA / cm². 2 The pulse width is 2s, the pulse interval is 2s, the pulse count is 300, and the total deposition time is 600s.
[0055] The working electrode was removed and cleaned thoroughly. It was then used as the working electrode, with a graphite rod as the counter electrode and Hg / HgO as the reference electrode, and immersed in a 1M KOH solution to construct an electrochemical system. The working electrode was activated using cyclic voltammetry. The scan rate was controlled at 50 mV / s, the scan range was 0.3–1 V vs. Hg / HgO, and the number of cycles was 50.
[0056] Remove the working electrode, clean it thoroughly, and you have NiFeSe. x / NF electrode material.
[0057] This electrode material can be directly used in the oxygen evolution reaction of water electrolysis. Specifically, it is used as the anode in the oxygen evolution reaction (OER).
[0058] Example 5
[0059] NiCuSe prepared using nickel foam (NF) as a substrate x / NF electrode materials
[0060] Cut the nickel foam into 1 cm × 2 cm pieces, and ultrasonically clean them with acetone, ethanol and deionized water for 30 min each, then dry them at 60℃ for 60 min before use.
[0061] NiCl₂·6H₂O, Cu(CO₂CH₃)₂·H₂O, and SeO₂ were dissolved in 50 mL of deionized water at a molar ratio of 1:1:1 and stirred until homogeneous to obtain a precursor solution, which was then poured into an electrolytic cell. A dual-electrode system was constructed using nickel foam as the working electrode and a platinum sheet as the counter electrode for pulse electrodeposition. The pulse current density was controlled at 30 mA / cm². 2 The pulse width is 2s, the pulse interval is 2s, the pulse count is 300, and the total deposition time is 600s.
[0062] The working electrode was removed and cleaned thoroughly. It was then used as the working electrode, with a graphite rod as the counter electrode and Hg / HgO as the reference electrode, and immersed in a 1M KOH solution to construct an electrochemical system. The working electrode was activated using cyclic voltammetry. The scan rate was controlled at 50 mV / s, the scan range was 0.3–1 V vs. Hg / HgO, and the number of cycles was 50.
[0063] Remove the working electrode, clean it thoroughly, and you have NiCuSe. x / NF electrode material.
[0064] This electrode material can be directly used in the oxygen evolution reaction of water electrolysis. Specifically, it is used as the anode in the oxygen evolution reaction (OER).
[0065] Comparative Example 1
[0066] The procedure was carried out according to Example 1, except that after forming a catalyst layer on a nickel foam substrate by pulse electrodeposition, no electrochemical activation treatment was performed. All other steps and control parameters were the same as in Example 1. This Comparative Example 1 was used to confirm the effect of electrochemical activation treatment on the morphology and composition of the electrode material.
[0067] Comparative Example 2
[0068] The procedure was carried out according to Example 1, except that constant current electrodeposition was performed at a current density of 30 mA / cm². 2 The total deposition time was 300 seconds.
[0069] Comparative Example 3
[0070] Referring to patent CN115852425A, a nickel-cobalt based catalyst was prepared by a hydrothermal method:
[0071] NiCl₂·6H₂O and CoCl₂·6H₂O were dissolved in deionized water and magnetically stirred until clear. Urea was then added, and stirring continued. The mixture was then transferred to a hydrothermal reactor and reacted at high temperature for 12 h. The solid was collected by centrifugation. The obtained solid was washed successively with ultrapure water and ethanol, and then vacuum dried to obtain the product. The product was ground, immersed in Na₂S solution, centrifuged, and freeze-dried to obtain the catalyst of Comparative Example 3. After room temperature sulfidation, the morphology of the nickel-cobalt layered double hydroxide precursor nanosheets was retained on the surface of the material.
[0072] Comparative Example 4
[0073] Referring to patent CN116479468A, the catalyst was prepared by constant current electrodeposition.
[0074] A Ni rod (anode) and a pretreated 316L stainless steel substrate (cathode) were connected to an electrochemical workstation. The substrate was polished, cleaned with dilute hydrochloric acid and deionized water, and then air-dried. Constant current electrodeposition was performed under magnetic stirring and a vertical external magnetic field to obtain the catalyst of Comparative Example 4. This catalyst initially consisted of amorphous nickel-cobalt-phosphorus nanoclusters, which underwent surface reconstruction into an upright nanosheet structure during water electrolysis.
[0075] Part Two: Test Results and Analysis
[0076] 1. Effects of electrochemical activation treatment on the morphology and properties of the catalyst layer
[0077] Scanning electron microscopy Figure 1 (a) It was observed that the surface morphology of the catalyst layer in the electrode material of Comparative Example 1 was relatively rough, with some micron-sized spherical particles, uneven particle distribution, and large agglomeration. Figure 1 (b) NiCoSe, the electrode material in Example 1 xThe scanning electron microscope (SEM) images of the catalyst layer on the / NF surface show that the catalyst layer on the surface of the electrode material prepared by this invention has a rich pore structure, which is beneficial to exposing more specific surface area and thus providing more active sites.
[0078] from Figure 2 The X-ray diffraction (XPS) pattern in the image shows that the electrode material of Example 1 has obvious cobalt and nickel phases, indicating that NiCoSe x The catalyst layer on the / NF surface is a nickel-cobalt-selenium oxide composite material. In contrast, the electrode material in Comparative Example 1 exhibits five distinct diffraction peaks, which correspond to the standard card diffraction peaks of nickel selenide and cobalt selenide, indicating that nickel-cobalt-selenium elements were successfully loaded onto the substrate in Comparative Example 1.
[0079] Based on the above scanning electron microscopy comparison, it can be seen that the surface pore structure of the electrode material without electrochemical activation treatment is not obvious and has few surface active sites. After electrochemical activation, it exhibits a porous structure and increased porosity. Oxygen vacancies are usually enriched at the pore edges or grain boundaries, which is beneficial for providing more active sites for OER. Based on the comparison of X-ray diffraction patterns, it can be seen that the diffraction peaks of the selenium phase in Example 1 have disappeared, leaving only the corresponding diffraction peaks of the cobalt and nickel phases. This indicates that the electrochemical activation treatment of the working electrode by cyclic voltammetry has caused the selenium phase in the catalyst layer to detach.
[0080] Figure 3 The EPR spectra of Example 1 and Comparative Example 1 are shown. The EPR spectrum of Example 1 shows a strong signal of g = 2.003, which is because electrons are trapped at defect sites, confirming that a large number of oxygen vacancies were formed during the electrochemical activation process in Example 1.
[0081] Figures 4-6 The XPS spectra of Ni, Co, and Si in Example 1 and Comparative Example 1 show that the binding energy of the nickel and cobalt phases decreased after electrochemical activation treatment, indicating a reduction phenomenon. Furthermore, the diffraction peaks of the selenium phase disappeared after electrochemical oxidation treatment, indicating that it detached from the electrode surface.
[0082] Figure 7 The XPS plots of O1s for Example 1 and Comparative Example 1 show that the lattice oxygen content decreases and the vacancy oxygen content increases in Example 1.
[0083] Figure 8 The XPS full spectra of Example 1 and Comparative Example 1 show that the O1s content decreased and the Se3d peak disappeared during the electrochemical oxidation process, further illustrating the above conclusions.
[0084] comprehensive Figures 2-6Based on the XPS spectra and the above analysis: On the one hand, this invention exhibits preferential Se extraction, providing space for the formation of oxygen vacancies; on the other hand, due to rapid structural recombination and charge compensation mechanisms, and due to the shedding of selenium phase material, Se... 2- After dissolution leads to an increase in the oxidation state of metallic Ni / Co, charge neutrality needs to be maintained through charge balance. Oxygen vacancies can act as charge compensation defects to stabilize the high-valence metal state. Due to reaction kinetic limitations, oxygen vacancies are left to maintain charge balance, resulting in a decrease in the binding energy between the nickel and cobalt phases.
[0085] Based on the above analysis, it is shown that the selenium phase material in the electrode material after electrochemical activation treatment of the present invention is detached, oxygen vacancies increase, and a richer pore structure is formed, which is conducive to exposing more active sites and providing a larger specific surface area, which has an important impact on improving the material performance.
[0086] 2. Practical application effect of the electrode material of the present invention in OER reaction
[0087] The electrode material prepared by this invention can be directly used as an anode for the oxygen evolution reaction in water electrolysis.
[0088] To investigate the practical application effect of the catalyst layer on the electrode material surface in the OER reaction, the electrode materials prepared in Examples 1-5 and Comparative Examples 2-4 of this invention were used to construct three-electrode systems connected to a CHI1140E electrochemical workstation to evaluate the OER electrochemical performance of the materials. The electrode material (1cm×2cm), graphite rod, and Hg / HgO of this invention were used as the working electrode, counter electrode, and reference electrode, respectively.
[0089] The catalytic performance of the electrode material was tested using the linear voltammetry (LSV) method.
[0090] The LSV testing conditions were as follows: at room temperature, tests were performed in 1M KOH solution at a scan rate of 5 mV / s. All LSV reactions were corrected for using iR compensation (80%).
[0091] The measured potential of the OER is converted to a reversible hydrogen electrode (RHE) according to the following equation:
[0092] E(vs.RHE)= E(vs.Hg / HgO)+0.098+0.059×pH
[0093] Examples 1-5 at 1000mA / cm 2 The specific data on voltage and overpotential under these conditions are shown in Table 1.
[0094] Table 1:
[0095]
[0096] Experimental results show that at a current density of 1000 mA / cm², 2 In this embodiment, the electrode material prepared exhibits a low overpotential, indicating that the catalyst layer prepared according to the present invention possesses high catalytic activity under high electrical density. Furthermore, the nickel-cobalt compound formed after selenium removal in Example 1 has the lowest overpotential compared to nickel-iron and nickel-copper compounds.
[0097] To further verify the catalytic effect of this embodiment, linear voltammetry tests were performed on the electrode materials of Examples 1-3 and Comparative Examples 2-4 under the same experimental conditions. The overpotential data at different current densities are shown in Table 2.
[0098] Table 2:
[0099]
[0100] Experimental results show that the catalysts prepared in Comparative Examples 2-4 have significantly higher overpotentials and lower catalytic activity under the same test conditions than those in this example.
[0101] Figure 9 The linear current-voltage (LSV) curves of Examples 1-3 and Comparative Example 2 provide a more intuitive illustration of the effects of this embodiment. The results show that the electrode material of this invention outperforms existing products. Compared with the constant current deposition method of Comparative Example 2, the catalytic efficiency of the catalyst prepared by pulse electrodeposition in this invention is significantly improved. In particular, the catalyst prepared in Example 1 under the conditions of a pulse width of 2s and a pulse interval of 2s (time ratio 1:1) exhibits the highest catalytic activity.
[0102] The present invention further addresses the electrode material of Example 1 at 1000 mA / cm -2 Under these conditions, a 24-hour durability test was conducted. Figure 10 As can be seen from the IT test curve, the electrode material of Example 1 maintains a stable voltage of around 1.8V for 24 hours, exhibiting strong stability. This is attributed to the structural stability maintained by the extraction of selenium phase and the formation of oxygen vacancies; this further demonstrates that the present invention possesses both high catalytic efficiency and strong stability, showing promising prospects for OER applications.
[0103] The above description is merely an example and illustration of the structure of the present invention, but the scope of protection of this patent is not limited thereto. Modifications or additions to the specific embodiments described, or substitutions made by those skilled in the art, as long as they do not deviate from the structure of the present invention or exceed the scope defined in these claims, shall all fall within the scope of protection of the present invention.
Claims
1. A method for preparing electrode materials by pulse electrodeposition, characterized in that, include: (1) Dissolve a transition metal salt and a selenium source in deionized water and stir until homogeneous to obtain a precursor solution; the transition metal is one or more of nickel, cobalt, iron or copper; (2) Using nickel foam as the working electrode and platinum sheet as the counter electrode, the precursor solution was added to the electrolytic cell to build a dual-electrode electrolytic system; the transition metal ions and selenium ions were co-deposited on the working electrode by pulse electrodeposition, and a catalyst layer containing transition metals and selenides was formed on the surface of the working electrode. (3) After cleaning the working electrode, immerse it in an alkaline solution along with the graphite counter electrode and the Hg / HgO reference electrode to build an electrochemical system. The working electrode is electrochemically activated by cyclic voltammetry to induce the selenium phase in the catalyst layer of the working electrode to detach. The surface of the catalyst layer is reconstructed to form a porous metal oxide, thus obtaining the electrode material for the oxygen evolution reaction of water electrolysis. The alkaline solution is a KOH solution with a concentration of 1M; when performing electrochemical activation treatment using cyclic voltammetry, the control parameters are: scan rate 50 mV / s, scan range 0.3–1 V. vs Hg / HgO, 50 cycles.
2. The method according to claim 1, characterized in that, The transition metal salt is a nitrate, chloride, or acetate.
3. The method according to claim 1, characterized in that, The selenium source is selenium dioxide.
4. The method according to claim 1, wherein in the precursor solution, the molar ratio of each transition metal ion to selenium ion is 1:
1.
5. The method according to claim 1, characterized in that, In step (2), before using nickel foam, the nickel foam is ultrasonically cleaned with acetone, ethanol and deionized water for 10 to 30 minutes respectively, and then dried at 60°C for 30 to 60 minutes.
6. The method according to claim 1, characterized in that, When co-depositing using pulsed electrodeposition, the control parameters are: pulse current density 30 mA / cm², pulse width 2 s, pulse interval 0.4–10 s, and total deposition time 360–1800 s.
7. The application of the electrode material prepared by the method according to any one of claims 1 to 6 in the oxygen evolution reaction of water electrolysis.