High-performance nickel-based catalyst, preparation method thereof and application of high-performance nickel-based catalyst in industrial-grade seawater electrolysis

Abstract

The invention discloses a high-performance nickel-based catalyst, a preparation method thereof and application of the high-performance nickel-based catalyst in industrial-grade seawater electrolysis. The preparation method of the high-performance nickel-based catalyst comprises the following steps: putting a pretreated self-supporting nickel-based metal material into a mixed aqueous solution containing heteropolyacid, ferric salt and cobalt salt for soaking reaction, and after the reaction is completed, washing and drying to obtain the high-performance nickel-based catalyst. According to the nickel-based catalyst, doping of trace iron and cobalt elements and leaching and re-adsorption of heteropoly acid in alkaline electrolyte promote rapid reconstruction of the surface of the nickel substrate, the performance of resisting seawater chloride ion corrosion and other impurity poisoning is enhanced, and then the stability of the catalyst under the high current density in the alkaline seawater environment is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of seawater electrolysis, and in particular to a high-performance nickel-based catalyst, a preparation method thereof, and an application thereof in industrial-grade seawater electrolysis. Background Art

[0002] In recent years, the rapid development of offshore wind power technology and the regional scarcity of fresh water have promoted the research and development process of renewable energy coupled with direct seawater electrolysis to produce green hydrogen. Compared with the hydrogen evolution reaction (HER), the oxygen evolution reaction (OER) is a process with higher energy in the water splitting reaction because it essentially involves more complex multiple proton / electron coupling steps. Therefore, the development of efficient OER electrocatalysts is very important for the overall efficiency of the water splitting reaction. In addition, compared with the fresh water environment, the oxidation and evolution of a large amount of chloride ions in seawater at the anode reduces the OER selectivity, and the strong binding between chloride ions and other dissolved ions and impurities and the active sites of the electrocatalyst will accelerate the corrosion and failure of the catalyst, resulting in poor durability of the catalyst. This deteriorates the performance of seawater electrolysis electrocatalysts. In addition, electrolysis at high current densities is crucial for the practical application of seawater electrolysis technology, but the above problems are more serious than at low current densities (<200 mA cm -2 ). To date, the highest current density at which most reported seawater electrocatalysts can operate continuously is still lower than the industrial requirement of 500 mA cm -2 , and it is rare for electrocatalysts to operate stably for more than 100 h. Therefore, there is an urgent need for an anti-poisoning oxygen evolution catalyst with sufficient catalytic activity and stability that can work normally in a harsh seawater environment and at a current density that meets industrial requirements.

[0003] Currently, Liu et al.

https: / / doi.org / 10.1016 / j.apcatb.2024.124140

https: / / doi.org / 10.1016 / j.apcatb.2024.124259

[0004] The present invention solves the problems existing in the prior art, provides a high-performance nickel-based catalyst, a preparation method thereof, and an application in industrial-grade seawater electrolysis, and provides reliable technical support for solving the accommodation of offshore wind power.

[0005] The present invention is realized through the following technical solutions: The first object of the present invention is to provide a preparation method of a high-performance nickel-based catalyst, including the following steps: immersing a pretreated self-supporting nickel-based metal material in a mixed aqueous solution containing a heteropolyacid, an iron salt, and a cobalt salt for soaking reaction, and after the reaction is completed, washing and drying to obtain the high-performance nickel-based catalyst.

[0006] By immersing the self-supporting nickel-based metal material in an aqueous solution containing a heteropolyacid, a cobalt salt, and an iron salt for a period of time, a high-performance seawater OER catalyst (i.e., a nickel-based electrode) can be obtained. The doping of trace Fe and Co and the leaching and re-adsorption of the heteropolyacid enhance the OER activity and stability of the catalyst in alkaline seawater, and it can stably electrolyze for 100 hours at an amperometric current density of 1000 mA cm -2

[0007] The present invention utilizes the synergistic effect between heteropolyacids and metal salts to break through the stability bottleneck of traditional nickel-based catalysts in a seawater environment, realizing the rapid preparation of an OER catalyst with high activity and high stability for seawater electrolysis, and providing key material support for an offshore wind energy-seawater electrolysis coupling system. The breakthrough of this technology not only promotes the industrial development of OER catalysts for seawater electrolysis, but also lays a material foundation for the commercial application of offshore wind power hydrogen production technology.

[0008] Preferably, the pretreatment steps of the self-supporting nickel-based metal material after pretreatment are as follows: After cutting the self-supporting nickel-based metal material, it is respectively immersed in hydrochloric acid, acetone, and deionized water for treatment, and then dried in vacuum at 50 °C to obtain the pretreated self-supporting nickel-based metal material. Further preferably, the self-supporting nickel-based metal material is respectively immersed in hydrochloric acid, acetone, and deionized water and ultrasonically treated for 15 min, and then dried at 50 °C in a vacuum oven.

[0009] Preferably, the self-supporting nickel-based metal material is selected from one of nickel foam, nickel mesh, and nickel felt.

[0010] Preferably, the concentration of the heteropolyacid in the mixed aqueous solution is 0.001-0.1 mol / L, and the heteropolyacid is selected from one or more of phosphotungstic acid, silicotungstic acid, borotungstic acid, phosphotungstovanadic acid, phosphomolybdic acid, phosphomolybdovanadic acid, phosphotungstomolybdic acid, and silicomolybdic acid.

[0011] Further preferably, the concentration of the heteropolyacid in the mixed aqueous solution is 0.001-0.002 mol / L. When the heteropolyacid is a mixture of two or more acids, the added concentration of each acid is equal.

[0012] Preferably, the concentration of the iron salt in the mixed aqueous solution is 0.001-1 mol / L, and the iron salt is selected from one of ferric nitrate, ferric sulfate, and ferric chloride; the concentration of the cobalt salt in the mixed aqueous solution is 0.001-1 mol / L, and the cobalt salt is selected from one of cobalt nitrate and cobalt chloride.

[0013] Further preferably, the concentration of the iron salt in the mixed aqueous solution is 0.05-1 mol / L, and the concentration of the cobalt salt in the mixed aqueous solution is 0.05-1 mol / L.

[0014] Preferably, the ratio of the surface area (cm 2 ) of the self-supporting nickel-based metal material to the dosage (mL) of the mixed aqueous solution is 0.1-2:1. Further preferably, the ratio of the surface area (cm 2 ) of the self-supporting nickel-based metal material to the dosage (mL) of the mixed aqueous solution is 1:1.

[0015] Preferably, the soaking reaction time is 10-3600 s.

[0016] Further preferably, the soaking reaction time is 30 - 360 s.

[0017] The specific conditions for washing and drying are as follows: washing with deionized water and ethanol and drying by air blowing; the air blowing drying temperature is 50°C - 80°C, and the drying time is 0.5 - 6.0 h.

[0018] The second object of the present invention is to provide a high-performance nickel-based catalyst prepared by the preparation method described above.

[0019] The third object of the present invention is to provide the application of the high-performance nickel-based catalyst in industrial-grade seawater electrolysis.

[0020] Preferably, the high-performance nickel-based catalyst serves as the working electrode. The Hg / HgO electrode serves as the reference electrode, and the platinum electrode serves as the counter electrode.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The doping of trace iron and cobalt elements in the nickel-based catalyst proposed by the present invention and the leaching and re-adsorption of heteropolyacid in the alkaline electrolyte promote the rapid reconstruction of the nickel substrate surface, enhance the performance of resisting seawater chloride ion corrosion and poisoning by other impurities, and thus improve the stability of the catalyst at high current density in the alkaline seawater environment.

[0022] (2) The catalyst proposed by the present invention is simple, controllable, time-saving and energy-saving in preparation, and can be scaled up for production. This can significantly reduce the production cost of seawater electrolysis catalysts, is beneficial to promoting the development of industrial-grade seawater electrolysis hydrogen production technology, and is beneficial to promoting the consumption of offshore wind power. Description of the Drawings

[0023] Figure 1 : SEM image of the catalyst prepared in Example 1.

[0024] Figure 2 : SEM image of the catalyst prepared in Comparative Example 5.

[0025] Figure 3 : SEM image of the catalyst prepared in Comparative Example 6.

[0026] Figure 4 : SEM image of the catalyst prepared in Comparative Example 7.

[0027] Figure 5 : Stability diagram of the catalyst obtained in Example 1 in the alkaline seawater electrolyte. Detailed Embodiments

[0028] The present invention will be further described in detail below in conjunction with embodiments. These embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. For the experimental methods without specific conditions in the following embodiments, they are generally carried out according to the conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are regarded as raw materials and reagents that can be obtained through commercial channels such as the conventional market. The concentration of hydrochloric acid is 1 mol / L.

[0029] Example 1 A preparation method of a high-performance nickel-based catalyst for industrial seawater electrolysis includes the following steps: S1. Cut the nickel foam into 3 cm × 5 cm, then immerse it in hydrochloric acid, acetone, and deionized water respectively, perform ultrasonic treatment for 15 min, and then dry it at 50 °C in a vacuum oven to complete the pretreatment operation.

[0030] S2. Prepare a 15 mL mixed aqueous solution containing 0.001 mol / L phosphomolybdovanadic acid, 0.001 mol / L borotungstic acid, 0.05 mol / L ferric chloride, and 0.05 mol / L cobalt chloride. Immerse the nickel foam pretreated in step S1 into the above mixed aqueous solution for soaking reaction for 60 s. After the reaction, wash it successively with deionized water and ethanol, and dry it with hot air at 70 °C for 2 h to finally obtain a high-performance nickel-based catalyst.

[0031] Example 2 A preparation method of a high-performance nickel-based catalyst for industrial seawater electrolysis includes the following steps: S1. Cut the nickel foam into 3 cm × 5 cm, then immerse it in hydrochloric acid, acetone, and deionized water respectively, perform ultrasonic treatment for 15 min, and then dry it at 50 °C in a vacuum oven to complete the pretreatment operation.

[0032] S2. Prepare a 15 mL mixed aqueous solution containing 0.001 mol / L phosphomolybdic acid, 0.001 mol / L borotungstic acid, 0.05 mol / L ferric chloride, and 0.05 mol / L cobalt chloride. Immerse the nickel foam pretreated in step S1 into the above mixed aqueous solution for soaking reaction for 60 s. After the reaction, wash it successively with deionized water and ethanol, and dry it with hot air at 70 °C for 2 h to finally obtain a high-performance nickel-based catalyst.

[0033] Example 3 A preparation method of a high-performance nickel-based catalyst for industrial seawater electrolysis includes the following steps: S1. Cut the nickel foam into 3 cm × 5 cm, then immerse it in hydrochloric acid, acetone, and deionized water respectively, perform ultrasonic treatment for 15 min, and then dry it at 50 °C in a vacuum oven to complete the pretreatment operation.

[0034] S2. Prepare a 15 mL mixed aqueous solution containing 0.001 mol / L phosphotungstic vanadic acid, 0.001 mol / L silicomolybdic acid, 0.05 mol / L ferric chloride, and 0.05 mol / L cobalt chloride. Immerse the nickel foam obtained in S1 into the above mixed aqueous solution for 60 s. After the reaction, wash it with deionized water and ethanol and dry it in a forced-air oven at 70 °C for 2 h to finally obtain a high-performance nickel-based catalyst.

[0035] Example 4 A preparation method of a high-performance nickel-based catalyst for industrial seawater electrolysis includes the following steps: S1. Cut the nickel foam into 3 cm × 5 cm, immerse it in hydrochloric acid, acetone, and deionized water respectively, perform ultrasonic treatment for 15 min, and then dry it in a vacuum oven at 50 °C to complete the pretreatment operation.

[0036] S2. Prepare a 15 mL mixed aqueous solution containing 0.0005 mol / L phosphomolybdic acid, 0.0005 mol / L silicomolybdic acid, 0.0005 mol / L phosphotungstic vanadic acid, 0.05 mol / L ferric chloride, and 0.05 mol / L cobalt chloride. Immerse the nickel foam obtained in S1 into the above mixed aqueous solution for 60 s. After the reaction, wash it with deionized water and ethanol and dry it in a forced-air oven at 70 °C for 2 h to finally obtain an electrolytic seawater catalyst.

[0037] Example 5 Same as Example 1, except that: the concentration of phosphomolybdovanadic acid in the mixed aqueous solution is 0.0005 mol / L, the concentration of borotungstic acid is 0.0005 mol / L, the concentration of ferric chloride is 0.025 mol / L, the concentration of cobalt chloride is 0.025 mol / L, the ratio of the surface area (cm 2 ) of the nickel foam to the dosage (mL) of the mixed aqueous solution is 0.1:1, the reaction time is 10 s, the forced-air drying temperature is 50 °C, and the drying time is 6 h.

[0038] Example 6 Same as Example 1, except that: the concentration of phosphomolybdovanadic acid in the mixed aqueous solution is 0.05 mol / L, the concentration of borotungstic acid is 0.05 mol / L, the concentration of ferric chloride is 1 mol / L, the concentration of cobalt chloride is 1 mol / L, the ratio of the surface area (cm 2 ) of the self-supporting nickel-based metal material to the dosage (mL) of the mixed aqueous solution is 2:1, the reaction time is 3600 s, the forced-air drying temperature is 80 °C, and the drying time is 0.5 h.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 lies in that: in S2, tungstoboric acid is not added, and the addition amount of phosphomolybdovanadic acid is changed to 0.002 mol / L. The rest is the same as in Example 1.

[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 1 lies in that: in S2, phosphomolybdovanadic acid is not added, and the addition amount of tungstoboric acid is changed to 0.002 mol / L. The rest is the same as in Example 1.

[0041] Comparative Example 3 The difference between Comparative Example 3 and Example 1 lies in that: in S2, cobalt chloride is not added, and the addition amount of ferric chloride is changed to 0.1 mol / L. The rest is the same as in Example 1.

[0042] Comparative Example 4 The difference between Comparative Example 4 and Example 1 lies in that: in S2, ferric chloride is not added, and the addition amount of cobalt chloride is changed to 0.1 mol / L. The rest is the same as in Example 1.

[0043] Comparative Example 5 The difference between Comparative Example 5 and Example 1 lies in that: in S2, tungstoboric acid and phosphomolybdovanadic acid are not added, the addition amount of ferric chloride is changed to 0.051 mol / L, and the addition amount of cobalt chloride is changed to 0.051 mol / L. The rest is the same as in Example 1.

[0044] Comparative Example 6 The difference between Comparative Example 6 and Example 1 lies in that: in S2, ferric chloride and cobalt chloride are not added, the addition amount of tungstoboric acid is changed to 0.051 mol / L, and the addition amount of phosphomolybdovanadic acid is changed to 0.051 mol / L. The rest is the same as in Example 1.

[0045] Comparative Example 7 The difference between Comparative Example 7 and Example 1 lies in that: in S2, tungstoboric acid, phosphomolybdovanadic acid, ferric chloride and cobalt chloride are not added. The rest is the same as in Example 1.

[0046] The catalysts prepared in Example 1 ( Figure 1 ), Comparative Example 5 ( Figure 2 ), Comparative Example 6 ( Figure 3 ), and Comparative Example 7 ( Figure 4 ) were characterized by scanning electron microscopy (SEM). It can be clearly seen that there is a synergistic effect between the heteropolyacid and the metal salt, which can promote their deposition on the surface of nickel foam. Inductively coupled plasma optical emission spectrometry (ICP-OES, Table 1) also confirmed that the use of the metal salt promoted the deposition of the heteropolyacid on the surface of nickel foam and increased the loading amount of electrochemically active substances on the surface of nickel foam.

[0047] Table 1. Comparison of ICP-OES test results of Example 1 and Comparative Examples 5-7

[0048] In addition, the electrolytic seawater catalysts prepared in Examples 1-6 and Comparative Examples 1-7 were respectively subjected to OER tests. The electrochemical tests were carried out on an electrochemical workstation (CHI660E) using a standard three-electrode system, in which the Hg / HgO electrode was used as the reference electrode, the platinum electrode was used as the counter electrode, and the high-performance nickel-based catalysts obtained in Examples 1-6 and Comparative Examples 1-7 of the present invention were used as the working electrodes (cut into 1 cm × 1 cm). The electrolytes were 1 M KOH and 1 M KOH + seawater. The overpotentials at a current density of 100 mA / cm 2 were compared, and the results are shown in Table 2. In addition, the alkaline seawater electrolysis stability test was carried out using the electrode obtained in Example 1 ( Figure 5 ).

[0049] Table 2. Comparison of overpotential data of Examples 1-6 and Comparative Examples 1-7 at a current density of 100 mA cm -2

[0050] It can be clearly seen from the SEM test results that there is a synergistic effect between the heteropolyacid and the metal salt, which can promote their surface modification on the nickel foam. The ICP-OES test results further confirmed that the use of the metal salt promoted the deposition of the heteropolyacid on the surface of the nickel foam, thereby increasing the loading amount of the electrochemically active substance on the surface of the nickel foam. Combining with Table 2, it can be seen that during the three-electrode OER test, the catalysts prepared in the examples have excellent OER activity both in alkaline pure water and alkaline seawater electrolyte. From the comparison of the overpotentials of the catalysts prepared in Example 1 and Comparative Examples 1-7, it can be seen that there is a synergistic effect between the heteropolyacid, cobalt salt and iron salt, which can significantly enhance the anti-poisoning ability of the catalyst in the seawater environment and improve the OER activity of the catalyst for electrolyzing seawater. In addition, the chronoamperometry curve of the catalyst prepared in Example 1 at a current density of 1000 mA / cm 2 showed almost no attenuation after electrolyzing seawater for up to 100 h. This indicates that the electrocatalyst prepared in the present invention has excellent catalytic activity and stability and is expected to be used in industrial seawater electrolysis.

[0051] The description of the above embodiments is only used to help understand the technical solution and its core idea of the present invention. It should be noted that for those skilled in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a high-performance nickel-based catalyst, characterized in that, It includes the following steps: immersing the pretreated self-supported nickel-based metal material in a mixed aqueous solution containing heteropolyacid, iron salt and cobalt salt for reaction, and after the reaction is completed, washing and drying to obtain the high-performance nickel-based electrode described above.

2. The preparation method according to claim 1, wherein The pretreatment step of the pretreated self-supported nickel-based metal material is: cutting the self-supported nickel-based metal material and then immersing it in hydrochloric acid, acetone and deionized water for treatment respectively, and drying it in vacuum at 50 °C to obtain the pretreated self-supported nickel-based metal material.

3. The preparation method according to claim 1 or 2, characterized in that, The self-supported nickel-based metal material is selected from one of nickel foam, nickel mesh and nickel felt.

4. The preparation method according to claim 1 or 2, characterized in that In the mixed aqueous solution, the concentration of the heteropolyacid is 0.001-0.1 mol / L, and the heteropolyacid is selected from one or more of phosphotungstic acid, silicotungstic acid, borotungstic acid, phosphotungstovanadic acid, phosphomolybdic acid, phosphomolybdovanadic acid, phosphotungstomolybdic acid and silicomolybdic acid.

5. The preparation method according to claim 1, characterized in that In the mixed aqueous solution, the concentration of the iron salt is 0.001-1 mol / L, and the iron salt is selected from one of iron nitrate, iron sulfate and iron chloride; the concentration of the cobalt salt in the mixed aqueous solution is 0.001-1 mol / L, and the cobalt salt is selected from one of cobalt nitrate and cobalt chloride.

6. The preparation method according to claim 1, characterized in that The ratio of the surface area of the self-supported nickel-based metal material to the dosage of the mixed aqueous solution is 0.1-2:

1.

7. The preparation method according to claim 1, characterized in that, The soaking reaction time is 10-3600 s.

8. The high-performance nickel-based catalyst prepared by the preparation method according to any one of claims 1-7.

9. The application of the high-performance nickel-based catalyst according to claim 8 in industrial-grade seawater electrolysis.

10. The application according to claim 9, wherein The high-performance nickel-based catalyst described above is used as an oxygen evolution electrode.

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