阅读说明：本技术 一种不锈钢基催化剂及其制备方法与应用 (Stainless steel-based catalyst and preparation method and application thereof ) 是由 潘晖 周鹏飞 王双鹏 吴嘉伟 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种不锈钢基催化剂及其制备方法与应用,属于电解技术领域。该不锈钢基催化剂由不锈钢在含NaCl的溶液中进行阳极氧化后而得。通过采用含NaCl的溶液对不锈钢进行阳极氧化,可增加不锈钢的催化活性,暴露更多的活性位点。相应的阳极氧化方法简单,易操作。将所得的不锈钢基催化剂用作全解水的有效双功能电催化剂,可在大电流密度下具有优异的活性和良好的耐久性,其在电池电压仅为2.83V和3.72V时可实现500mA/cm～(2)和1000mA/cm～(2)的高效碱性电解水,并且循环1000圈极化曲线之后,其性能不但没有衰减,反而有稍微增长的趋势,在工业化电解水制氢的中具有良好的应用前景。(The invention discloses a stainless steel-based catalyst and a preparation method and application thereof, belonging to the technical field of electrolysis. The stainless steel-based catalyst is obtained by anodizing stainless steel in a NaCl-containing solution. By anodizing the stainless steel with the NaCl-containing solution, the catalytic activity of the stainless steel can be increased, and more active sites can be exposed. The corresponding anodic oxidation method is simple and easy to operate. The obtained stainless steel-based catalyst is used as an effective bifunctional electrocatalyst for total hydrolysis, has excellent activity and good durability at high current density, and can realize 500mA/cm at cell voltages of only 2.83V and 3.72V 2 And 1000mA/cm 2 And circulating 10 the high efficiency alkaline electrolyzed waterAfter 00 circles of polarization curve, the performance of the material is not attenuated but slightly increased, and the material has good application prospect in industrial hydrogen production by water electrolysis.)

1. The stainless steel-based catalyst is characterized by being prepared by anodizing stainless steel in a NaCl-containing solution;

preferably, the stainless steel is in the form of a block.

2. Stainless steel based catalyst according to claim 1, wherein the stainless steel has a chemical composition, in weight percent, of: 10-15% of Ni, 10-15% of Co, 2-5% of Cr, 1-3% of Mo, 0.1-0.5% of C and the balance of Fe.

3. Stainless steel based catalyst according to claim 1 or 2, wherein said stainless steel based catalyst has a nanoporous structure.

4. The method for producing a stainless steel based catalyst according to any one of claims 1 to 3, comprising the steps of: anodizing the stainless steel in a NaCl-containing solution.

5. The method according to claim 4, wherein the NaCl concentration of the NaCl-containing solution is 3-4 wt.%, preferably 3.5 wt.%.

6. The method as claimed in claim 4, wherein the current density of the anodic oxidation is 750-850mA/cm²The treatment time is 1-4min, preferably 2-3min, more preferably 3 min.

7. The method for producing according to claim 4, wherein the production of the stainless steel comprises: 3D printing stainless steel powder with a preset chemical composition into bulk stainless steel;

preferably, 3D printing is carried out in a laser cladding forming mode;

preferably, the process conditions of laser cladding forming include: the power is 800-1500W, the laser sweep speed is 5-15mm/s, and the layer thickness is 0.2-1 mm.

8. The method according to claim 7, wherein the stainless steel powder is obtained by co-aerosolizing the respective elements providing the composition;

preferably, the process conditions for aerosolization include: the melting temperature is 1600-1700 ℃, the atomization pressure is 3-4MPa, and the protective atmosphere is argon.

9. The preparation method according to claim 4, characterized in that, before the anodic oxidation treatment, the method further comprises the steps of surface grinding, polishing, cleaning and drying the stainless steel to be treated;

preferably, after the anodic oxidation treatment, the method further comprises the steps of cleaning and drying the treated stainless steel;

preferably, the cleaning agent for cleaning the anodized stainless steel includes water and ethanol.

10. Use of a stainless steel based catalyst according to any of claims 1 to 3 as a catalyst for hydrogen evolution reaction and/or a catalyst for oxygen evolution reaction during water electrolysis;

preferably, the stainless steel-based catalyst serves as a catalyst for both a hydrogen evolution reaction and an oxygen evolution reaction in the full water splitting process.

Technical Field

The invention relates to the technical field of electrolysis, in particular to a stainless steel-based catalyst and a preparation method and application thereof.

Background

The problems of environmental pollution and energy exhaustion have attracted people's attention all over the world. Hydrogen is considered one of the most efficient, clean energy sources. The electrolysis of water provides a simple method for producing high-purity hydrogen for people, and the electrolysis of water is widely concerned in the field of hydrogen production.

However, the hydrogen produced by the water electrolysis method in the industry accounts for less than 4% of the hydrogen produced by the whole industry, which is mainly due to the lack of high-efficiency electrocatalyst. Suitable catalysts can accelerate the decomposition of water while reducing the consumption of energy, thereby improving the hydrogen production efficiency. The electrolysis of water is mainly divided into two half-reactions: the Hydrogen Evolution Reaction (HER) at the cathode and the Oxygen Evolution Reaction (OER) at the anode. High efficiency and low energy consumption HER and OER catalysts are critical to the electrocatalytic decomposition of water to produce hydrogen.

Commercially commonly used electrocatalysts are mainly Pt-based HER catalysts and Ru or Ir-based OER catalysts. Although such catalysts can be effective in reducing operating voltage, their widespread use is limited due to their scarcity and high cost. Therefore, there is an urgent need to design and develop a high-efficiency non-noble metal water-decomposition electrocatalyst.

Currently, high efficiency non-noble metal based HER (oxide, phosphide, chalcogenide) and OER (oxide, hydroxide, chalcogenide, nitride) catalysts have achieved good research results. However, such catalysts are primarily powders or grown on foamed nickel or other supports. Such contact between the catalyst and the support increases the interfacial resistance and reduces the conductivity of the catalyst, thereby affecting the catalytic activity. And the active material solution falls off from the substrate during a long-term catalytic test, which seriously affects the life of the catalyst, and the shortcomings limit the commercial application of most of the catalysts developed at present.

Therefore, the development of low cost, efficient, long-lived self-supporting non-noble metal catalysts is of great importance for large-scale application to the commercial electrolytic water hydrogen production industry.

The stainless steel-based catalyst is low in price and simple in preparation method, so that more and more attention is paid. However, the surface treatment of stainless steel-based catalysts under different conditions often only improves the OER performance, which greatly limits the application of the stainless steel-based catalysts. The development of the bifunctional stainless steel-based catalyst with high-efficiency HER and OER performances is very important for hydrogen production by industrial electrolysis.

In view of this, the invention is particularly proposed.

Disclosure of Invention

It is an object of the present invention to provide a stainless steel based catalyst which is capable of having both high HER and OER performance.

The second object of the present invention is to provide a method for preparing the above stainless steel-based catalyst.

The invention also aims to provide an application of the stainless steel-based catalyst, such as a catalyst for hydrogen evolution reaction and/or a catalyst for oxygen evolution reaction in the water electrolysis process.

The application can be realized as follows:

in a first aspect, the present application provides a stainless steel-based catalyst obtained by anodizing stainless steel in a solution containing NaCl.

In an alternative embodiment, the stainless steel is in the form of a block.

In an alternative embodiment, the stainless steel has the following chemical composition in percentage by weight: 10-15% of Ni, 10-15% of Co, 2-5% of Cr, 1-3% of Mo, 0.1-0.5% of C and the balance of Fe.

In an alternative embodiment, the stainless steel based catalyst has a nanoporous structure.

In a second aspect, the present application provides a method of making a stainless steel based catalyst according to any one of the preceding embodiments, comprising the steps of: the stainless steel is anodized in a solution containing NaCl.

In an alternative embodiment, the concentration of NaCl in the NaCl-containing solution is 3-4 wt.%, preferably 3.5 wt.%.

In an alternative embodiment, the current density of the oxidation during anodization is 750-²The treatment time is 1-4 min;

in a preferred embodiment, the treatment time is 2-3min, more preferably 3 min.

In an alternative embodiment, the preparation of the stainless steel comprises: 3D printing stainless steel powder with a preset chemical composition into bulk stainless steel.

In an optional embodiment, a laser cladding forming mode is adopted for 3D printing.

In an alternative embodiment, the process conditions of laser cladding forming include: the power is 800-1500W, the laser sweep speed is 5-15mm/s, and the layer thickness is 0.2-1 mm.

In an alternative embodiment, the stainless steel powder is obtained by co-aerosolization of the elements providing the composition.

In an alternative embodiment, the process conditions for aerosolization include: the melting temperature is 1600-1700 ℃, the atomization pressure is 3-4MPa, and Ar gas is used as protective atmosphere.

In a preferred embodiment, the process conditions for aerosolization include: the melting temperature is 1650 ℃, the atomization pressure is 3.5MPa, and Ar gas is used as protective atmosphere.

In an alternative embodiment, before the anodizing treatment, the surface grinding, polishing, cleaning and drying of the stainless steel to be treated are further included.

In an alternative embodiment, after the anodizing treatment, the method further comprises washing and drying the treated stainless steel.

In an alternative embodiment, the cleaning agent for cleaning the anodized stainless steel comprises water and ethanol.

In a third aspect, the present application provides the use of a stainless steel based catalyst as in the previous embodiments, for example as a catalyst for hydrogen evolution reactions and/or as a catalyst for oxygen evolution reactions during water electrolysis.

In an alternative embodiment, the stainless steel based catalyst acts as a catalyst for both the hydrogen evolution reaction and the oxygen evolution reaction during the full hydrolysis process.

The beneficial effect of this application includes:

by using a pair of solutions containing NaClThe stainless steel is anodized, so that the catalytic activity of the stainless steel can be increased, and more active sites are exposed. The corresponding anodic oxidation method is simple and easy to operate. The obtained stainless steel-based catalyst is used as an effective bifunctional electrocatalyst for total hydrolysis, has excellent activity and good durability at high current density, and can realize 500mA/cm at cell voltages of only 2.83V and 3.72V²And 1000mA/cm²The performance of the high-efficiency alkaline electrolyzed water is not attenuated but slightly increased after the 1000-circle polarization curve is circulated, and the high-efficiency alkaline electrolyzed water has a good application prospect in industrial hydrogen production by electrolyzing water.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is an SEM micrograph of a stainless steel based catalyst provided in example 1 of the present application;

FIG. 2 is a SEM high magnification view of a stainless steel based catalyst provided in example 1 of the present application;

FIG. 3 is a graph showing the hydrogen evolution polarization curves of stainless steel in a KOH solution of 1mol/L at different treatment times in the experimental examples of the present application;

FIG. 4 is a graph showing the oxygen evolution polarization curves of stainless steel-based catalysts in a 1mol/L KOH solution at different treatment times in the experimental examples of the present application;

FIG. 5 is a polarization curve of total water splitting of a stainless steel-based catalyst treated with a salt solution having a concentration of 3.5 wt% for 3 minutes in the experimental examples of the present application.

Detailed Description

In order to make the objects, 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. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The stainless steel-based catalyst provided by the present application, and the preparation method and application thereof are specifically described below.

The application provides a stainless steel-based catalyst, which is obtained by anodizing stainless steel in a NaCl-containing solution.

The stainless steel is a finished stainless steel product, and preferably, the stainless steel is FeNiCoCr stainless steel.

In an alternative embodiment, the stainless steel may have a chemical composition, in terms of weight percentage, of: 10-15% of Ni, 10-15% of Co, 2-5% of Cr, 1-3% of Mo, 0.1-0.5% of C and the balance of Fe.

The Ni content may be referred to as 10%, 11%, 12%, 13%, 14%, 15%, etc., and may be any other value within a range of 10 to 15%.

The content of Co may be 10%, 11%, 12%, 13%, 14%, 15%, or the like, or may be any other value within the range of 10 to 15%.

The content of Cr may be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, or the like, or may be any other value within the range of 2 to 5%.

The content of Mo may be 1%, 1.5%, 2%, 2.5%, 3%, or the like, or may be any other value within the range of 1 to 3%.

The content of C may be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or the like, or may be any other value within the range of 0.1 to 0.5%.

The stainless steel may be in the form of a block, and may be in other forms as needed. It is worth to be noted that the 3D bulk stainless steel has the ability to control its pore system, its thickness and area, its specific surface area, and its catalytic performance by regulation of 3D printing process, and does not need additional supporting electrodes, compared to other stainless steels. By reference, the specific dimensions of the bulk stainless steel provided herein may be: 10 mm. times.10 mm. times.1 mm. In addition, the size can be set to other sizes according to actual conditions.

The stainless steel-based catalyst provided herein has a nanoporous structure. Specifically, it shows micron-sized pores under a low-power scanning electron microscope, and shows extremely small size (about 200 nm pores on the surface) and a nano-porous structure under a high-power scanning electron microscope. The structure can enable the stainless steel to provide more active sites in a catalytic process, and is favorable for having excellent activity and good durability under high current density.

Correspondingly, the application also provides a preparation method of the stainless steel-based catalyst, which mainly comprises the following steps: the stainless steel is anodized in a NaCl-containing solution (which can be understood as a "salt solution" or "NaCl solution" or "seawater").

In an alternative embodiment, the preparation of the stainless steel may comprise: the stainless steel powder with the chemical composition provided by the application is 3D printed into bulk stainless steel, for example, the 3D printing can be carried out by adopting a laser cladding forming mode, and other 3D printing modes can also be adopted.

Stainless steel (blocky) is prepared by adopting a 3D printing technology, and the pores and the structure of the stainless steel can be regulated and controlled by regulating technological parameters, so that the active area of the stainless steel is increased.

By reference, the process conditions of laser cladding forming may include: the power is 800-1500W (such as 800W, 1000W, 1200W or 1500W, etc.), the laser sweep speed is 5-15mm/s (such as 5mm/s, 8mm/s, 10mm/s, 12mm/s or 15mm/s, etc.), and the layer thickness is 0.2-1mm (such as 0.2mm, 0.5mm, 0.8mm or 1mm, etc.). It is worth noting that by setting the power, laser sweep rate and layer thickness to the above ranges, it is ensured that the stainless steel powder can be melted and strongly bonded together.

In an alternative embodiment, the stainless steel powder described above may be co-aerosolized with the elements providing the composition.

By reference, the process conditions for aerosolization include: the melting temperature is 1600-1700 ℃ (preferably 1650 ℃), and the atomization pressure is 3-4MPa (preferably 3.5MPa) Ar gas is used as the protective atmosphere.

Further, before the anodic oxidation treatment, the surface grinding, polishing, cleaning and drying are carried out on the stainless steel to be treated. Subsequently, an anodic oxidation treatment is performed.

In alternative embodiments, the concentration of NaCl in the NaCl-containing solution used in the anodization process may be 3 to 4 wt%, such as 3 wt%, 3.5 wt%, or 4 wt%, etc., and may be any other value within the range of 3 to 4 wt%. But is preferably 3.5%.

It is worth noting that when the concentration of the NaCl solution is lower than 3 wt%, the corrosion is easy to be too slow, the corrosion effect is not obvious, and when the concentration is higher than 4 wt%, the alloy is easy to be over-corroded, and the performance of the alloy is reduced.

In an alternative embodiment, the current density of the oxidation during anodization may be 750-850mA/cm²E.g. 750mA/cm²、760mA/cm²、770mA/cm²、780mA/cm²、790mA/cm²、800mA/cm²、810mA/cm²、820mA/cm²、830mA/cm²、840mA/cm²Or 850mA/cm²Etc., and may be 750-850mA/cm²Any other value within the range.

The treatment time may be 1-4min, such as 1min, 1.5min, 2min, 2.5min, 3min, 3.5min or 4min, or any other value within 1-4 min. Preferably, the treatment time is 2-3min, more preferably 3 min.

It is worth noting that when the current density of the anodic oxidation is too low (e.g., less than 750 mA/cm)²) Or the treatment time is too short (shorter than 1min), which easily causes the surface corrosion of the stainless steel to be insufficient, and the performance improvement is limited; if the current density of the anodic oxidation is too high (e.g. above 850 mA/cm)²) Or the treatment time is too long (longer than 4min), the surface of the stainless steel is easy to excessively corrode, and uniform corrosion pits cannot be formed.

It is emphasized that, the application for the first time treats the surface of the stainless steel by adopting the method of anodic oxidation of the solution containing NaCl, so that the treated stainless steel has a nano-porous structure, more active sites are exposed, and the catalytic activity of the treated stainless steel is remarkably increased.

Further, after the anodic oxidation treatment, the method also comprises the steps of cleaning and drying the treated stainless steel. The cleaning agent for cleaning the stainless steel after the anodic oxidation treatment can comprise water (preferably deionized water) and ethanol. The number of washing is preferably plural.

In addition, the application also provides the application of the stainless steel-based catalyst, for example, the stainless steel-based catalyst is used as a catalyst for hydrogen evolution reaction and/or a catalyst for oxygen evolution reaction in the water electrolysis process.

Preferably, the above-mentioned stainless steel-based catalyst serves as a catalyst for both hydrogen evolution reaction and oxygen evolution reaction in the full water splitting process.

In light of the above, the stainless steel-based catalyst obtained by performing surface anodization treatment on the 3D printing-based stainless steel (FeNiCoCr) developed by the present application is low in cost, and has excellent activity and good durability at a large current density when used as an effective bifunctional electrocatalyst for total hydrolysis. The stainless steel has relatively high HER and OER catalytic performances when treated in 3.5 wt% NaCl solution for 3 minutes. In a 1mol/L KOH electrolyte, the electrodes required overpotentials of 358mV and 618mV to provide 100mA/cm for HER and Steel-3min (meaning 3min of stainless Steel treated with 3.5 wt% NaCl-containing solution)²And 300mA/cm²Current density; for OER, 100mA/cm is provided at overpotentials of 390mV and 613mV²And 300mA/cm²The current density. The above bifunctional catalyst electrode can also realize 500mA/cm at cell voltages of only 2.83V and 3.72V²And 1000mA/cm²The performance of the high-efficiency alkaline electrolyzed water is not attenuated but slightly increased after the 1000-circle polarization curve is circulated, and the high-efficiency alkaline electrolyzed water has a good application prospect in industrial hydrogen production by electrolyzing water.

The features and properties of the present invention are described in further detail below with reference to examples.

Example 1

This example provides 5 stainless steel based catalysts, which were made by anodizing Fe-Ni-Co-Cr stainless steel prepared by 3D printing techniques in a NaCl containing solution for different times. The above-described anodizing process can improve the catalytic performance of stainless steel.

Wherein the chemical composition of the Fe-Ni-Co-Cr stainless steel is shown in Table 1, and the dimension is 10mm multiplied by 1 mm.

TABLE 1 chemical composition of Fe-Ni-Co-Cr stainless steel

Element(s)

Ni

Co

Cr

Mo

C

Fe

Content (%)

11.3

13.5

4.6

2.2

0.2

Balance of

The main preparation process of the stainless steel-based catalyst is as follows:

(1) Fe-Ni-Co-Cr stainless steel powder is prepared by a gas atomization method. Wherein, the main technological parameters of the gas atomization process comprise: the melting temperature is 1650 ℃, the atomization pressure is 3.5MPa, and Ar gas is used as protective atmosphere.

(2) And preparing the Fe-Ni-Co-Cr stainless steel powder into a bulk alloy by adopting a laser cladding forming technology. The laser cladding forming technology mainly comprises the following technological parameters: the power is 1200W, the laser sweep speed is 10mm/s, and the layer thickness is 0.5 mm.

(3) And (4) grinding, polishing, cleaning and drying the surface of the block alloy for later use.

(4) 3.5 wt% sodium chloride solution was prepared.

(5) Anodizing the stainless steel alloy treated in the step (3) in the NaCl solution prepared in the step (4), wherein the current density of the oxidization is 800mA/cm²The treatment time is 0min, 1min, 2min, 3min and 4min respectively.

(6) The anodized sample was repeatedly washed with deionized water and ethanol several times, and dried.

The obtained stainless steel-based catalyst (treatment for 3min as an example) was observed by a scanning electron microscope, and the results are shown in FIGS. 1 and 2. As can be seen from fig. 1 and 2, at low power, the stainless steel treated with the salt solution of the above concentration for 3 minutes has pores of micron order (fig. 1), and at high power, the bifunctional catalyst is seen to have an extremely small size and a nanoporous structure (fig. 2), indicating that the catalyst has a large specific surface area, which is advantageous for catalytic effect.

Test examples

(1) The C rod is used as an anode, stainless steel with different anodic oxidation times is used as a cathode, a 1mol/L KOH solution is used as an electrolyte, and the hydrogen evolution performance of the stainless steel with different anodic oxidation times is tested.

(2) And testing the oxygen evolution performance of the stainless steel at different anodic oxidation times by using a C rod as a cathode, stainless steel at different anodic oxidation times as an anode and 1mol/L KOH solution as electrolyte.

(3) And respectively adopting stainless steel subjected to anodic oxidation for 3min as a cathode and an anode, and adopting a 1mol/L KOH solution as electrolyte to test the full-hydrolytic performance of the stainless steel subjected to anodic oxidation for 3 min.

The results are shown in table 2 and fig. 3 to 5.

TABLE 2 comparison of Hydrogen and oxygen evolution Performance and Total hydrolysis Performance of Fe-Ni-Co-Cr stainless steels

As can be seen from Table 1, the above stainless steel has relatively high HER and OER catalytic performance when treated in 3.5 wt% NaCl solution for 3 minutes. In a 1mol/L KOH electrolyte, only 358mV and 618mV overpotentials for HER and Steel-3min electrodes are required to provide 100mA/cm²And 300mA/cm²Current density; for OER, 500mA/cm was achieved with overpotentials of 390mV and 613mV providing voltages of only 2.83V and 3.72V²And 1000mA/cm²The high-efficiency alkaline electrolyzed water.

As can be seen from fig. 3, the HER performance of the stainless steel was significantly improved as the anodizing time was prolonged, and the HER performance of the stainless steel was slightly decreased when the anodizing time exceeded 3 minutes. It was demonstrated that at this concentration of NaCl solution (3.5 wt%) and at a current density (800mA/cm), the HER performance of stainless steel was best when anodized for 3 minutes.

As can be seen from fig. 4, the OER performance of the stainless steel was significantly improved as the anodizing time was prolonged, and slightly decreased as the anodizing time was prolonged, after exceeding 3 minutes. It was confirmed that the current density (800mA/cm) was neutralized in a NaCl solution (3.5 wt%) at such a concentration²) Then, after anodizing for 3 minutes, the OER performance of the stainless steel is the best.

As can be seen from a combination of fig. 3 and 4, the best HER and OER catalytic performance was achieved simultaneously after 3 minutes of anodization of the stainless steel in NaCl solution (3.5 wt%). Thus, the stainless steel treated for 3 minutes constitutes a full electrolysis water electrode, which is used as a bifunctional catalyst. As can be seen from FIG. 5, the stainless steel has excellent catalytic performance at a large current density, and only 2.83V and 3.72V are required to realize 500mA/cm²And 1000mA/cm²The high-efficiency alkaline electrolyzed water. The catalyst has good stability, and the catalytic energy is high after 1000 cycles of circulationThe current density is slightly increased.

Comparative example 1

Neutralization at 800mA/cm in 3.5 wt% NaCl solution was carried out using 316L and 304 stainless steel as materials²The current density was anodized for 3 minutes and HER and OER performance in a 1mol/L KOH solution was tested using a C-bar counter electrode and compared to the anodized stainless steel based catalyst in this application, with the results shown in table 3.

TABLE 3 comparison of Hydrogen and oxygen evolution Performance of Fe-Ni-Co-Cr stainless steels and 316L and 304 stainless steels

As can be seen from Table 3, the Fe-Ni-Co-Cr stainless steel provided by the present application has higher catalytic performance for HER and OER than 316L and 304 stainless steel after being anodized under the same conditions.

Comparative example 2

Stainless steel identical to the present application was anodized in 3.5 wt% NaCl solution using different current densities and times and tested for HER and OER performance in 1mol/L KOH solution using a C-bar as counter electrode and anodized as described herein (current density of 800mA/cm)²Treatment time of 3min) was shown in Table 4.

TABLE 4 comparison of Hydrogen and oxygen evolution Performance under different Current and time anodizing of Fe-Ni-Co-Cr stainless steels

As can be seen from Table 3, both the current density and the anodization time during the anodization treatment have a significant effect on the catalytic performance of HER and OER of the stainless steel-based catalyst, and the catalyst within the scope of the present application can have higher catalytic performance of HER and OER than the range.

Comparative example 3

With 3.5 wt.% of a further solution (NaF, NaNO)₃、Na₂SO₄) For anodizing the solutions, the same stainless steels as the present application were used at 800mA/cm in these solutions²The results of the anodization treatment at current density for 3 minutes and the testing of HER and OER performance in a 1mol/LKOH solution using a C-bar as the counter electrode are shown in table 5 in comparison to the anodized stainless steel based catalyst of the present application.

TABLE 5 comparison of the Hydrogen and oxygen evolution Performance of Fe-Ni-Co-Cr stainless steels in NaCl solutions and other solutions

As can be seen from Table 5, the solution used for the anodization has a significant effect on the catalytic performance of the stainless steel-based catalyst, and the NaCl-containing solution used in the present application is superior to NaF and NaNO₃、Na₂SO₄The stainless steel-based catalyst obtained after treatment has higher HER and OER catalytic performances.

In conclusion, by anodizing the stainless steel with the solution containing NaCl, the catalytic activity of the stainless steel can be increased, exposing more active sites. The corresponding anodic oxidation method is simple and easy to operate. The obtained stainless steel-based catalyst is used as an effective bifunctional electrocatalyst for full water electrolysis, has excellent activity and good durability under high current density, and has good application prospect in industrial hydrogen production by water electrolysis.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.