Ultrasonic impregnation preparation method of nickel alloy type electrolytic catalyst

Abstract

The invention discloses an ultrasonic impregnation preparation method of a nickel alloy type electrolytic catalyst. The ultrasonic impregnation preparation method comprises the steps of substrate pretreatment, precursor preparation and catalyst film preparation. Through the mode, the ultrasonic impregnation preparation method of the nickel alloy type electrolytic catalyst can replace a Pt-based catalyst which is high in cost, a synergistic effect is generated through interaction of two or more metal elements, the catalytic performance, stability and corrosion resistance of the alloy catalyst under high-concentration alkaline large current are improved, HER reaction is facilitated, and the nickel alloy type electrolytic catalyst can be used for preparing a high-efficiency electrolytic catalyst. And moreover, the dependence on single noble metal is reduced, the production cost of the catalyst can be remarkably reduced, and the resource utilization efficiency, the energy efficiency and the environmental friendliness are improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to an ultrasonic impregnation preparation method of a nickel alloy type electrolytic catalyst. Background Art

[0002] The development of human society and industrial production mainly rely on energy drive. However, energy conversion and supply based on traditional fossil fuels are not only inefficient, but also face a large amount of carbon dioxide emissions, leading to serious greenhouse effects and environmental ecological problems, posing serious challenges to the sustainable development of human society and environmental protection. Therefore, the development of low-carbon and clean renewable energy has become a consensus among countries around the world. The development of efficient and clean water decomposition hydrogen production technology has become one of the key directions for the development of hydrogen energy. Among them, water electrolysis hydrogen production is an ideal, clean and renewable energy technology because it has no harmful gas emissions and no pollution. It can play a significant role in the sustainable energy system. Wind energy, solar energy, tidal energy, etc. can be used to provide electricity for water electrolysis hydrogen production, allowing this technology to be developed in the long run.

[0003] However, in the process of hydrogen production from alkaline aqueous solution, water consumption around the catalyst leads to a rapid increase in the local pH value, which leads to its deactivation. Currently, the most common high-performance water electrolysis catalyst is still a platinum-based precious metal catalyst. The high cost and rarity of platinum limit its feasibility in large-scale applications. Therefore, it is necessary to design and develop low-cost alloy catalysts suitable for high-concentration alkaline solutions. Summary of the invention

[0004] In order to solve the above technical problems, a technical solution adopted by the present invention is: Provided is a method for preparing a nickel alloy electrolytic catalyst by ultrasonic impregnation, the steps of which include: (1) Substrate pretreatment Take 50 mL of 1 mol / L KOH solution and 20 g of polysorbate-80, dissolve them in 50 mL of deionized water, and heat them in a water bath to 80 °C. After they are completely dissolved, a cleaning solution is prepared. The nickel substrate is immersed in the cleaning solution for 60 min to remove the grease on the surface of the nickel substrate. Take out the cleaned nickel substrate, rinse it with deionized water for several times until the pH value reaches neutral, and then put the nickel substrate in a drying oven and dry it at 60 °C. (2) Preparation of precursor (2.1) Prepare 20-100 mL of an organic solution of an organic solvent and deionized water with a concentration of 2 mol / L, and add 0.02-0.5 mol of a metal salt to the organic solution to prepare a mixed solution; wherein the metal salt includes one of a cobalt salt, a manganese salt, an iron salt, and a copper salt; (2.2) immersing the nickel substrate treated in step (1) into the mixed solution, and performing ultrasonic immersion treatment on the nickel substrate and the mixed solution; (2.3) The nickel substrate and the mixed solution are transferred together for drying, and then placed in a muffle furnace for calcination for 3-5 hours. After the reaction, the mixture is cooled to room temperature to obtain a precursor. (3) preparing a nickel-based alloy catalyst on the precursor to obtain an electrode with a nickel-cobalt alloy catalyst film; (3.1) Weigh 0.01~0.1 mol of nickel salt and add it to 20~100 mL of 0.5~2 mol / L ethanol solution; (3.2) Add the precursor to the mixed solution prepared in step (3.1), and heat to evaporate the solution. Place the evaporated product in a tubular furnace and calcine it for 1 to 3 hours under a protective atmosphere at a calcination temperature of 200 to 800°C. Take it out after calcination to obtain a nickel-based alloy catalyst membrane electrode for use as an electrode in hydrogen production by water electrolysis.

[0005] In a preferred embodiment of the present invention, the nickel substrate includes nickel foam, nickel mesh or nickel plate.

[0006] In a preferred embodiment of the present invention, the alkaline solution includes one of a sodium hydroxide solution and a potassium hydroxide solution.

[0007] In a preferred embodiment of the present invention, the cobalt salt includes one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt acetate, cobalt acetylacetonate, and cobalt oxalate.

[0008] In a preferred embodiment of the present invention, the organic solvent includes one or more of n-hexane, n-heptane, toluene, chloroform, and ethyl acetate.

[0009] In a preferred embodiment of the present invention, the ultrasonic time is 10-60 minutes, the ultrasonic temperature is 20-40° C., and the ultrasonic power is 100W-500W.

[0010] In a preferred embodiment of the present invention, in step (2.3), the muffle furnace calcination temperature is 200-600°C, and the calcination time is 10-120 min.

[0011] In a preferred embodiment of the present invention, the nickel salt includes one or more of nickel chloride, nickel acetylacetonate, nickel acetate, nickel oxalate, nickel sulfate, and nickel nitrate.

[0012] In a preferred embodiment of the present invention, the protective atmosphere includes one or more of nitrogen, argon and helium.

[0013] A nickel alloy electrolytic catalyst is prepared by any of the above preparation methods.

[0014] The beneficial effects of the present invention are: it can replace the expensive Pt-based catalyst, produce a synergistic effect through the interaction of two or more metal elements, improve the catalytic performance, stability and corrosion resistance of the alloy catalyst under high-concentration alkaline and large current, which is beneficial to the HER reaction, and helps to reduce the dependence on a single precious metal, which can significantly reduce the production cost of the catalyst and improve resource utilization efficiency, energy efficiency and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 It is a schematic diagram comparing the structure of a nickel-based alloy catalyst for producing hydrogen by electrolysis of high-concentration alkaline solution and a pure substrate of the present invention; Figure 2 This is a HER test diagram of a nickel-based alloy catalyst for producing hydrogen by electrolysis of high-concentration alkaline solution according to the present invention; Figure 3 This is an OER test diagram of a nickel-based alloy catalyst for producing hydrogen by electrolysis of high-concentration alkaline solution according to the present invention; Figure 4 It is a stability test diagram of the electrode prepared by the present invention in a KOH test solution with a concentration of 30%. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1-4 , the embodiment of the present invention includes: A method for preparing a nickel alloy electrolytic catalyst by ultrasonic impregnation uses nickel foam, nickel plate or porous nickel mesh as the electrode substrate, prepares a nickel-based bimetallic (nickel-cobalt alloy) catalyst by in-situ loading, and successfully develops a high-efficiency and high-stability three-dimensional self-supporting membrane electrode. This provides a new idea for the development of high-efficiency and high-stability alkaline water electrolysis hydrogen production electrodes, so that the nickel-based bimetallic catalyst has excellent hydrogen production (catalytic activity) performance and good stability in a high-concentration alkaline water electrolysis system. The addition of other non-precious metal elements regulates the electronic structure of Ni, increases the charge transfer rate, and accelerates the reaction rate of electrochemical hydrogen evolution.

[0018] The ultrasonic impregnation preparation method of nickel alloy type electrolytic catalyst comprises the following steps: (1) Substrate pretreatment Take 50~100mL, 1 mol / L KOH solution and 20g~30g polysorbate-80, dissolve them in 20~60mL deionized water, and heat them in a water bath to 60~100℃. After complete dissolution, a cleaning solution is prepared. The nickel substrate is immersed in the cleaning solution for 10~120 min to remove grease on the surface of the nickel substrate. Take out the cleaned nickel substrate, rinse it with deionized water for multiple times until the pH value reaches neutral, and then put the nickel substrate in a drying oven and dry it at 60℃.

[0019] More preferably, the base comprises one of sodium hydroxide and potassium hydroxide.

[0020] (2) Preparation of precursor (2.1) Mix 0.02~0.5 mol of metal salt, 20~100 mL of deionized water and an organic solvent to prepare a mixed solution.

[0021] More preferably, the metal salt includes one of a cobalt salt, a manganese salt, an iron salt and a copper salt.

[0022] More preferably, the cobalt salt includes one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt acetate, cobalt acetylacetonate, and cobalt oxalate.

[0023] More preferably, the organic solvent includes one or more of n-hexane, n-heptane, toluene, chloroform and ethyl acetate.

[0024] (2.2) Immersing the nickel substrate in the mixed solution, and performing ultrasonic immersion treatment on the nickel substrate and the mixed solution.

[0025] Since ultrasound can generate tiny bubbles and acoustic cavitation effects in the mixed solution (impregnation solution), it can accelerate the penetration of cobalt ions in the nickel substrate, increase the impregnation speed, greatly shorten the processing time, and improve production efficiency; at the same time, the vibration of ultrasound helps to evenly distribute the cobalt ions, ensure uniform treatment of the surface and interior of the nickel substrate, improve the adhesion of cobalt ions to the nickel substrate, and enhance durability and stability; in addition, ultrasound can also promote chemical reactions and improve the reaction efficiency of the impregnation solution, thereby improving the functional properties of the nickel substrate. Compared with traditional methods, ultrasonic impregnation treatment has low production costs and is more energy-saving and emission-reducing.

[0026] More preferably, the ultrasonic time is 10-60 minutes, the ultrasonic temperature is 20-40° C., and the ultrasonic power is 100W-500W.

[0027] (2.3) The nickel substrate and the mixed solution are transferred together, dried, and placed in a muffle furnace for calcination for 3 to 5 hours. After the reaction, the mixture is cooled to room temperature to obtain the precursor.

[0028] More preferably, the muffle furnace calcination temperature is 200-600 °C.

[0029] (3) Preparing a nickel-based alloy catalyst on the precursor to obtain an electrode with a nickel-cobalt alloy catalyst.

[0030] (3.1) Weigh 0.01~0.1 mol of nickel salt and add it to 20~100 mL of a mixed solvent of deionized water and ethanol.

[0031] (3.2) Add the precursor to the mixed solution prepared in step (3.1), and heat to evaporate the solution. Place the evaporated product in a tubular furnace and calcine it for 1 to 3 hours under a protective atmosphere at a calcination temperature of 200 to 800°C. Take it out after calcination to obtain a nickel-based alloy catalyst membrane electrode for use as an electrode in hydrogen production by water electrolysis.

[0032] Further preferably, the nickel salt includes one or more of nickel chloride, nickel acetylacetonate, nickel acetate, nickel oxalate, nickel sulfate, and nickel nitrate.

[0033] Further preferably, the molar ratio of the nickel salt in step (3.1) to the cobalt salt in step (2.1) is 1:0.2 to 1:5.

[0034] More preferably, the calcination temperature is 200-800°C.

[0035] More preferably, the protective atmosphere includes one or more of nitrogen, argon and helium. Example

[0036] The ultrasonic impregnation preparation method of a nickel alloy type electrolytic catalyst comprises the following steps: 1) Substrate pretreatment Dissolve 6 g NaOH and 15 g Tween 80 in 60 mL deionized water to prepare an alkaline solution. Soak the nickel mesh in the alkaline solution and heat the alkaline solution to 60 °C for 20 min to remove the oily components on the surface of the nickel mesh. Then wash the nickel mesh with deionized water until the pH value is neutral and dry it at 60 °C.

[0037] 2) Preparation of nickel-based alloy catalyst precursor 0.05 mol of cobalt chloride was dissolved in 100 mL of a mixed solvent of ethanol and deionized water to obtain a mixed solution. The nickel mesh treated in step 1) was placed in the mixed solution, taken out after ultrasonic treatment for 30 minutes, and the nickel mesh was placed in an oven at 60°C for drying. The dried sample was calcined in a muffle furnace at 300°C in a nitrogen atmosphere for 60 minutes to obtain a precursor.

[0038] 3) Preparation of nickel-based alloy catalyst Take 0.1 mol nickel chloride and disperse it in 20~100mL of a mixed solvent of deionized water and ethanol, and the concentration of the mixed ethanol solvent is 1 mol / L. Add the precursor to the mixed solution prepared above, and heat it to evaporate the solution. Place the evaporated product in a tube furnace and calcine it at 600℃ in a nitrogen atmosphere for 1 hour. After cooling to room temperature, a nickel-based alloy (or nickel-cobalt alloy (NiCo)) catalyst membrane is obtained. The nickel mesh with the nickel-based alloy catalyst membrane can be used as an electrode for high-concentration water electrolysis to produce hydrogen. The synthesized sample photo is shown in the figure. Figure 1 shown.

[0039] 4) Electrochemical test The electrocatalytic hydrogen evolution performance of the nickel-cobalt alloy catalyst prepared in step 2) was tested by using an electrochemical workstation and a three-electrode system: the electrode with the nickel-cobalt alloy catalyst was used as the working electrode, Ag / AgCl was used as the reference electrode, the platinum sheet electrode was used as the counter electrode, and the electrolyte was a 30% KOH solution to simulate the alkaline solution conditions under working conditions. The linear sweep voltammetry method was used for the test on the electrochemical workstation with a scan rate of 5 mV / s.

[0040] Test results such as Figure 2-3 The electrode can show excellent hydrogen evolution activity and alkaline stability in high-concentration alkaline seawater electrolyte, and can reach a current density of 400 mA / cm in 30% KOH alkaline solution. -2 , the overpotential of HER is 413mV (without IR compensation). At the same time, in the actual operation of the electrolyzer, 4000 A / m -2 It can run stably for more than 2000 hours under high voltage. Example

[0041] According to the method of Example 1, except that the amount of nickel chloride and cobalt chloride added in step 2) is changed to 0.3 mol and 0.5 mol, and the rest is the same as Example 1, an electrode with a NiCo alloy catalyst suitable for high-concentration alkaline water electrolysis is obtained. Example

[0042] According to the method of Example 1, except that the metal salt used in step 2) is replaced by ferric chloride and cobalt chloride, and the rest is the same as Example 1, an electrode with a NiCo alloy catalyst suitable for electrolysis of high-concentration alkaline water is obtained.

[0043] The beneficial effects of the ultrasonic impregnation preparation method of a nickel alloy electrolytic catalyst of the present invention are: 1. This method has significant energy efficiency and environmental friendliness. Compared with the traditional high-temperature reduction method, the precursor preparation is synthesized at room temperature, which greatly reduces energy consumption. At the same time, ultrasound can reduce the occurrence of catalyst pore blocking, and the alloy synergistically further optimizes the surface atomic structure and electronic structure of the catalyst, which is more conducive to the HER reaction. 2. The alloy catalyst prepared by the present invention is suitable for alkaline seawater electrolyte. By introducing the cheap metal element Co as the second component to develop a NiCo bimetallic catalyst system, the two or more metal elements in the alloy catalyst can interact with each other to produce a synergistic effect, which can not only show high activity in the seawater electrolysis reaction, but also improve the catalytic performance and stability of the alloy catalyst under high-concentration alkaline and large current, and also have better corrosion resistance, so as to maintain good tolerance under high-concentration alkaline conditions, and have broad application prospects; 3. Alloy catalysts can replace expensive Pt-based catalysts, helping to reduce dependence on a single precious metal, significantly reducing the production cost of catalysts and improving resource utilization efficiency.

[0044] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing a nickel alloy electrolytic catalyst by ultrasonic impregnation, the steps comprising: (1) Substrate pretreatment Take 50-100 mL of 1 mol / L alkaline solution and 20 g-30 g of polysorbate-80, dissolve them in 20-60 mL of deionized water, and heat them in a water bath to 60-100 °C. After they are completely dissolved, a cleaning solution is prepared. The nickel substrate is immersed in the cleaning solution for 10-120 min to remove grease on the surface of the nickel substrate. The cleaned nickel substrate is taken out and rinsed with deionized water for multiple times until the pH value reaches neutral. The nickel substrate is placed in a drying oven and dried at 60 °C. (2) Preparation of precursor (2.1) preparing 20-100 mL of an organic solution of an organic solvent and deionized water with a concentration of 2 mol / L, and adding 0.02-0.5 mol of a metal salt to the organic solution to prepare a mixed solution; wherein the metal salt comprises one of a cobalt salt, a manganese salt, an iron salt, and a copper salt; (2.2) immersing the nickel substrate treated in step (1) into the mixed solution, and performing ultrasonic immersion treatment on the nickel substrate and the mixed solution; (2.3) The nickel substrate and the mixed solution are transferred into an oven at 60 °C for drying until dry, and then placed in a muffle furnace for calcination for 3-5 hours. After the reaction, the mixture is cooled to room temperature to obtain a precursor. (3) preparing a nickel-based alloy catalyst on the precursor to obtain an electrode with a nickel-cobalt alloy catalyst film; (3.1) Weigh 0.01~0.1 mol of nickel salt and add it to 20~100 mL of 0.5~2 mol / L ethanol solution; (3.2) Add the precursor to the mixed solution prepared in step (3.1), and heat to evaporate the solution. Place the evaporated product in a tubular furnace and calcine it for 1 to 3 hours under a protective atmosphere at a calcination temperature of 200 to 800°C. Take it out after calcination to obtain a nickel-based alloy catalyst membrane electrode for use as an electrode in hydrogen production by water electrolysis.

2. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The nickel substrate includes nickel foam, nickel mesh or nickel plate.

3. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The alkaline solution includes one of a sodium hydroxide solution and a potassium hydroxide solution.

4. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The cobalt salt includes one or more of cobalt chloride, cobalt nitrate, cobalt sulfate, cobalt acetate, cobalt acetate, cobalt acetylacetonate, and cobalt oxalate.

5. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The organic solvent includes one or more of n-hexane, n-heptane, toluene, chloroform and ethyl acetate.

6. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The ultrasonic time is 10 to 60 minutes, the ultrasonic temperature is 20 to 40°C, and the ultrasonic power is 100W to 500W.

7. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: In step (2.3), the muffle furnace calcination temperature is 200~600 ℃, and the calcination time is 10~120 min.

8. The method for preparing the nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The nickel salt includes one or more of nickel chloride, nickel acetylacetonate, nickel acetate, nickel oxalate, nickel sulfate, and nickel nitrate.

9. The method for preparing a nickel alloy electrolytic catalyst by ultrasonic impregnation according to claim 1, characterized in that: The protective atmosphere includes one or more of nitrogen, argon and helium.

10. A nickel alloy electrolytic catalyst, characterized in that: Prepared by the preparation method described in any one of claims 1 to 9.

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