High-chlorine-resistant ni-fe bulk alloy electrolytic seawater oxygen evolution catalyst and preparation method thereof
By constructing a multi-metal oxide/hydroxide/hydroxy oxide OER active layer and a tungsten trioxide/tungstate ion repellent layer on the surface of NiFe foam alloy, the problems of low OER activity and poor stability of NiFe-based catalysts in seawater electrolysis were solved, and a highly efficient and stable seawater electrolysis hydrogen production process was realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUIZHOU UNIV
- Filing Date
- 2026-04-01
- Publication Date
- 2026-06-05
AI Technical Summary
Existing NiFe-based oxide/hydroxide/hydroxy oxide catalysts exhibit low OER activity and poor stability in seawater electrolysis, failing to meet the requirements of low energy consumption and high current density in industrial seawater electrolysis. Furthermore, their preparation processes are cumbersome and yields are low, making large-scale application difficult.
By corroding NiFe foam alloy in ammonium tungstate solution to construct a multi-metal oxide/hydroxide/hydroxy oxide OER active layer and a tungsten trioxide/tungstate ion chlorine-repellent layer, the catalytic activity and chlorine resistance are improved. A high chlorine-resistant NiFe bulk alloy electrolytic seawater oxygen evolution catalyst is prepared in large size using a simple corrosion treatment method.
In a mixed solution of 3.5% NaCl and 1M KOH, the overpotential is only 355 mV at a current density of 500 mA cm⁻², and the stability exceeds 1000 h. It can also operate stably for 200 h in real alkaline seawater, demonstrating excellent OER activity and long-term stability.
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Figure CN122147382A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of alloy catalyst technology, specifically to a high chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis and its preparation method. Background Technology
[0002] Environmental pollution and energy shortages have drawn global attention. Hydrogen energy, as a high-energy-density, sustainable, and green energy source, has become a key alternative to traditional fossil fuels, effectively addressing environmental pollution and the energy crisis. Currently, the mainstream hydrogen production methods are fossil fuel-based and industrial by-product-based methods, which consume fossil fuels and pollute the environment, hindering the achievement of the "dual-carbon goal." Water electrolysis is a green and environmentally friendly hydrogen production technology; however, the scarcity of freshwater resources limits its development. Seawater resources are abundant, and seawater electrolysis is a key pathway to achieving large-scale green hydrogen production. However, seawater contains a large amount of Cl... -1 Chlorine-resistant oxygen evolution catalysts corrode electrode materials and compete with the oxygen evolution reaction (OER) at the anode, thus significantly reducing hydrogen production efficiency. Therefore, developing highly active and chlorine-resistant OER catalysts is an important means to achieve large-scale hydrogen production through seawater electrolysis.
[0003] Currently, OER catalysts for seawater electrolysis mainly include noble metal-based catalysts (Ru or Ir-based) and non-noble metal-based catalysts. While noble metal-based catalysts exhibit high catalytic activity, their scarcity and high cost limit their large-scale application. Non-noble metal-based catalysts (oxides, hydroxides, phosphides, nitrides, sulfides, etc.) have been extensively studied due to their low cost and high catalytic activity. Among them, NiFe-based oxides / hydroxides / hydroxyoxides have broad application prospects in seawater electrolysis due to their abundant reserves, low cost, tunable crystal and electronic structures, and high OER selectivity in chlorinated electrolytes. However, the OER activity of existing NiFe-based oxide / hydroxide / hydroxyoxide catalysts cannot yet meet the requirements of low energy consumption and high current density for industrial seawater electrolysis. At industrial current densities, the Cl in seawater... - This still results in low OER selectivity and poor stability. Moreover, these catalysts are mainly prepared through hydrothermal, electrodeposition, high-temperature treatment combined with in-situ electrochemical activation or redox methods, which have problems such as cumbersome processes, low yield, and size limitations, making it difficult to meet the needs of large-scale industrial seawater electrolysis applications.
[0004] NiFe bulk alloys can be prepared in large quantities and in large sizes, making them promising catalysts for the electrolysis of seawater for oxygen evolution. However, NiFe bulk alloys themselves have low catalytic activity and are not resistant to Cl. -Due to corrosion and competition from OER (oxygen evolution reaction), it cannot be directly used for seawater electrolysis. Using NiFe bulk alloys as oxygen evolution catalysts for seawater electrolysis requires addressing two issues simultaneously: first, enhancing catalytic activity by constructing a multi-metal oxide / hydroxide / hydroxy oxide OER active layer on the surface; and second, improving Cl-repellent properties by constructing a chlorine-repellent layer. - This results in low selectivity and poor stability of the OER. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a high-chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis and its preparation method. This invention effectively resists chloride ion corrosion, achieving excellent activity and long-term stability in the oxygen evolution reaction at high current densities, while also maintaining low preparation costs.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a high chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis oxygen evolution, characterized by preparation according to the following steps:
[0007] (1) The bulk NiFe foam alloy was ultrasonically cleaned in anhydrous ethanol;
[0008] (2) Dry the cleaned NiFe foam alloy and pickle it in hydrochloric acid solution;
[0009] (3) The pickled NiFe foam alloy is placed in the prepared corrosion solution and the corrosion is carried out for 5-20 hours at a temperature of 20-30℃; the corrosion solution is one of ammonium tungstate aqueous solution, ammonium molybdate aqueous solution, and ammonium chromate aqueous solution.
[0010] (4) Take out the constructed NiFe foam alloy and rinse the surface with deionized water to obtain a high chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis oxygen evolution.
[0011] In the above scheme, the corrosion solution is an aqueous solution of ammonium tungstate. The NiFe foam alloy surface is etched with an aqueous solution of ammonium tungstate to construct a multi-metal oxide / hydroxide / hydroxyoxide OER active layer and a tungsten trioxide / tungstate ion multi-layer chloride-repellent layer, thereby improving its oxygen evolution activity and stability in seawater electrolysis. The NiFe foam, after being etched with 0.1M ammonium tungstate aqueous solution, exhibits excellent OER activity and stability. In a mixed solution of 3.5% NaCl and 1M KOH, current densities of 500, 200, and 100 mA cm⁻¹ are used. -2 Under these conditions, the overpotentials are only 690, 443, and 355 mV. At 500 mA cm⁻¹ -2 It exhibits stability for over 1000 hours under certain conditions and can operate stably for over 200 hours in real alkaline seawater.
[0012] In the above scheme, the NiFe foam alloy composition is Ni5Fe5 or Ni7Fe3. It can also be any other NiFe foam alloy with any other proportion.
[0013] In the above scheme: the concentration of hydrochloric acid solution is 1-2M, and the pickling time is 1-2min.
[0014] In the above scheme, the concentration of the corrosive solution is 0.1M-0.5M.
[0015] In the above scheme: In step (2), the NiFe foam alloy is dried by wiping with dust-free paper or by air drying.
[0016] The high chlorine-resistant NiFe bulk alloy oxygen evolution catalyst for seawater electrolysis is prepared by a method described above.
[0017] Beneficial Effects: This invention aims to develop a highly efficient and chlorine-resistant oxygen evolution catalyst for seawater electrolysis based on NiFe bulk alloys, which can be fabricated in large sizes. The goal is to achieve excellent activity and long-term stability in the oxygen evolution reaction at high current densities, while maintaining low preparation costs. Commercial NiFe foam alloys are etched in a corrosive solution to construct a multi-metal oxide / hydroxide / hydroxyoxide OER active layer and a tungsten trioxide / tungstate ion multi-chlorine-repellent layer on their surface, thereby improving their intrinsic catalytic activity and chlorine resistance. -1 The NiFe alloy material exhibits excellent prospects for industrial water electrolysis hydrogen production after simple corrosion treatment. Attached Figure Description
[0018] Figure 1 The graphs show the oxygen evolution polarization curves of NiFe alloy after being etched in ammonium tungstate solution for different durations in a mixed solution of 3.5% NaCl and 1M KOH.
[0019] Figure 2 The oxygen evolution polarization curves of NiFe alloy after being etched in ammonium molybdate solution for different times in a mixed solution of 3.5% NaCl and 1M KOH are shown.
[0020] Figure 3 The graph shows the oxygen evolution polarization curves of NiFe alloy after being etched in ammonium chromate solution for different times in a mixed solution of 3.5% NaCl and 1M KOH.
[0021] Figure 4 The NiFe alloy after being etched in ammonium tungstate solution for 18 hours at 500 mA cm -2 Stability at current density.
[0022] Figure 5 The image shows a comparison of Raman spectroscopy before and after 18 hours of corrosion with ammonium tungstate aqueous solution.
[0023] Figure 6 This is a SEM image of the NiFe foam alloy surface after being etched by ammonium tungstate aqueous solution for 18 hours. Detailed Implementation
[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0025] Example 1
[0026] The high chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis oxygen evolution was prepared according to the following steps:
[0027] The bulk NiFe foam alloy (composition: Ni5Fe5) was placed in anhydrous ethanol and ultrasonically cleaned for 10 minutes.
[0028] After being cleaned with ethanol, the bulk NiFe foam was wiped dry with lint-free paper and then placed in a 1M hydrochloric acid solution for 1 minute and 30 seconds of acid washing.
[0029] Prepare 0.1M aqueous solutions of ammonium tungstate, ammonium molybdate, and ammonium chromate, respectively.
[0030] The pickled alloy blocks were placed in prepared aqueous solutions of ammonium tungstate, ammonium molybdate, and ammonium chromate for 5h, 10h, 15h, 18h, and 20h, respectively, at a corrosion temperature of 25℃.
[0031] The etched alloy was removed and its surface was rinsed with deionized water to obtain a high-chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis and oxygen evolution. The un-etched product was recorded as NiFe, and the products obtained after etching for 5h, 10h, 15h, 18h, and 20h were recorded as NiFe-5h, NiFe-10h, NiFe-15h, NiFe-18h, and NiFe-20h, respectively.
[0032] Table 1 shows the OER performance of NiFe foam alloys before and after corrosion by aqueous solutions of ammonium tungstate, ammonium molybdate, and ammonium chromate in a mixed solution of 3.5% NaCl and 1 M KOH.
[0033] Table 1
[0034]
[0035] As shown in Table 1, the OER performance of NiFe alloy improved to varying degrees after three solution corrosion treatments. Among these, ammonium molybdate corrosion treatment showed the most significant performance improvement under low current density and short corrosion time. Ammonium tungstate corrosion exhibited the best corrosion effect under high current density and long corrosion time. Overall, NiFe alloy showed the best oxygen evolution performance after 18 hours of ammonium tungstate corrosion.
[0036] Combining Table 1 and Figure 1 Data shows that the performance of the NiFe foam constructed in ammonium tungstate solution after 5 hours was significantly improved compared to the original foam. With prolonged corrosion time, the oxygen evolution activity initially increased and then slightly decreased. The NiFe alloy exhibited optimal catalytic activity after 18 hours of corrosion, requiring only overpotentials of 355, 443, and 690 mV to achieve 100, 200, and 500 mA cm⁻¹ values. -2 Current density.
[0037] Combining Table 1 and Figure 2 Data shows that the performance of the NiFe foam constructed in ammonium molybdate solution after 5 hours was significantly improved compared to the original foam. With prolonged corrosion time, the oxygen evolution activity initially increased and then slightly decreased. The NiFe alloy exhibited optimal catalytic activity after 18 hours of corrosion, requiring only overpotentials of 393, 493, and 765 mV to achieve 100, 200, and 500 mA cm⁻¹ values. -2 Current density.
[0038] Combining Table 1 and Figure 3 The data shows that after 5 hours of construction with ammonium chromate solution, the performance of the NiFe foam has been significantly improved compared to the original foam. However, the oxygen evolution performance does not change significantly with the extension of corrosion time.
[0039] Figure 4 The stability of NiFe alloy after 18 hours of corrosion with ammonium tungstate aqueous solution in a mixed solution of 3.5% NaCl and 1M KOH was tested. Compared with the untreated NiFe foam alloy, it has excellent stability and can operate stably for 1000 hours, showing good resistance to chloride ion corrosion and promising prospects for industrial application.
[0040] Figure 5 Raman spectral analysis after 18 hours of ammonium tungstate corrosion showed that, compared to the original NiFe alloy, the surface of the corroded sample was mainly composed of tungsten oxide (199, 351, and 972 cm⁻¹). -1 ), tungstates (366 and 521 cm) -1 ) and hydroxyl oxides (460, 654 and 1347 cm) -1 The catalyst is composed of hydroxyl oxides formed on its surface, which mainly act as catalytic active centers, enhancing OER activity. Meanwhile, tungsten oxides and tungstate ions mainly form a chloride-repellent layer, effectively resisting chloride ion corrosion and thus endowing the catalyst with excellent long-term stability. SEM images show that the NiFe foam surface, after corrosion treatment, is loaded with a large amount of particulate matter, which increases the specific surface area and significantly improves catalytic activity.
[0041] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention. For example, the corrosion construction temperature can be 20-30°C, the NiFe foam alloy can be Ni7Fe3 or other NiFe foam alloys, the concentration of the hydrochloric acid solution can be 1-2M, the pickling time can be 1-2 min, and the concentration of the corrosion solution can be 0.1M-0.5M. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a high-chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis oxygen evolution, characterized in that, Prepare according to the following steps: (1) The bulk NiFe foam alloy was ultrasonically cleaned in anhydrous ethanol; (2) Dry the cleaned NiFe foam alloy and pickle it in hydrochloric acid solution; (3) The pickled NiFe foam alloy is placed in the prepared corrosion solution and the corrosion is carried out for 5-20 hours at a temperature of 20-30℃; the corrosion solution is one of ammonium tungstate aqueous solution, ammonium molybdate aqueous solution, and ammonium chromate aqueous solution. (4) Take out the constructed NiFe foam alloy and rinse the surface with deionized water to obtain a high chlorine-resistant NiFe bulk alloy catalyst for seawater electrolysis oxygen evolution.
2. The preparation method of the high chlorine-resistant NiFe bulk alloy electrolytic seawater oxygen evolution catalyst according to claim 1, characterized in that: The corrosion solution is an aqueous solution of ammonium tungstate.
3. The preparation method of the high chlorine-resistant NiFe bulk alloy electrolytic seawater oxygen evolution catalyst according to claim 2, characterized in that: The composition of NiFe foam alloy is Ni5Fe5 or Ni7Fe3.
4. The preparation method of the high chlorine-resistant NiFe bulk alloy electrolytic seawater oxygen evolution catalyst according to claim 3, characterized in that: The concentration of the hydrochloric acid solution is 1-2M, and the pickling time is 1-2 minutes.
5. The preparation method of the high chlorine-resistant NiFe bulk alloy seawater electrolysis oxygen evolution catalyst according to claim 4, characterized in that: The concentration of the corrosive solution is 0.1M-0.5M.
6. The preparation method of the high chlorine-resistant NiFe bulk alloy electrolytic seawater oxygen evolution catalyst according to claim 5, characterized in that: In step (2), the NiFe foam alloy is dried by wiping with lint-free paper or by air drying.
7. A high chlorine-resistant NiFe bulk alloy oxygen evolution catalyst for seawater electrolysis prepared by the method described in any one of claims 1-6.