Preparation method of high-efficiency alkali-hydrogen industrial electrode and high-efficiency water electrolyser

Abstract

The invention provides a preparation method of a high-efficiency alkali-hydrogen industrial electrode and a high-efficiency water electrolyser, and the preparation method comprises the following steps: 1, dissolving 5-20g of molybdenum-containing metal salt, 5-20g of sulfur-containing reagent and 20-40g of iron-containing metal salt in 1600mL of deionized water in sequence to prepare a mixed solution, and immersing a substrate with a cleaned surface into the mixed solution; and 2, standing the mixed solution immersed in the nickel foam at room temperature for 24-48 hours, then taking out a sample, washing the sample, drying the sample in vacuum for 12-48 hours, and then annealing the sample in an environment of 25-300 DEG C for 0-12 hours to obtain the efficient alkali-hydrogen industrial electrode. A novel electrolysis environment is constructed by introducing a component structure with a self-protection mechanism, and the defects that a traditional electrode is low in energy efficiency, prone to inactivation and the like can be overcome.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen production by electrolysis of water, in particular to a method for preparing a high-efficiency alkali hydrogen industrial electrode, and also provides a high-efficiency water electrolyzer. Background Art

[0002] Science and technology are changing with each passing day, and the times are constantly moving forward. The fossil energy such as coal, oil, and natural gas accumulated by the earth for billions of years is being rapidly consumed, and the problems of energy shortage and environmental pollution are becoming increasingly prominent. In order to find clean and renewable new energy sources, people have turned their attention to the field of hydrogen production. Hydrogen has high energy density, can be stored and transported, has no carbon emissions when used, and is easy to reassemble into chemical raw materials. It is considered to be an ideal green energy carrier. In the current hydrogen production process, the water electrolysis hydrogen production process is completely decarbonized and the product purity is high. In particular, the application prospects of alkaline water electrolysis are outstanding. Combined with renewable surplus electricity to drive water electrolysis hydrogen production has broad social and economic benefits.

[0003] However, reducing the energy consumption of the electrolyzer and improving the stability of long-term operation under industrial conditions are still the core tasks of the current development of water electrolysis hydrogen production process. The power consumption mainly depends on the catalytic electrode, and the electrode accounts for about 60% of the cost of the electrolyzer, so the design of low-cost, high-efficiency electrodes is the key to the development of electrolyzers. At present, the most efficient water-splitting electrodes are precious metal Pt-based cathodes and Ru / Ir-based anodes. Due to limited resources and high costs, precious metal-based electrodes cannot meet the needs of industrial development; and traditional alkaline water electrolysis electrodes are very easy to fail and deactivate under industrial electrolysis conditions, thereby increasing the cost of use, which greatly limits the development of industrial water reduction electrolysis. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing an efficient alkali hydrogen industrial electrode, and also to provide an efficient water electrolyzer. By introducing a component structure with a self-protection mechanism, a new electrolysis environment is constructed to solve the shortcomings of traditional electrodes such as low energy efficiency and easy deactivation.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a high-efficiency alkali-hydrogen industrial electrode comprises the following steps:

[0007] Step 1: dissolve 5-20 g of a molybdenum-containing metal salt, 5-20 g of a sulfur-containing reagent, and 20-40 g of an iron-containing metal salt in 1600 mL of deionized water to prepare a mixed solution, and immerse the cleaned substrate in the mixed solution;

[0008] Step 2: Let the mixed solution immersed in nickel foam stand at room temperature for 24-48 hours, then take out the sample, rinse it and vacuum dry it for 12-48 hours, and then anneal it at 25-300°C for 0-12 hours to obtain the high-efficiency alkali hydrogen industrial electrode.

[0009] In one embodiment,

[0010] The molybdenum-containing metal salt is one of sodium molybdate and ammonium molybdate;

[0011] The sulfur-containing reagent is one of thioacetamide and thiourea;

[0012] The iron-containing metal salt is one of ferrous sulfate and ferric nitrate.

[0013] In one embodiment, the substrate is one of nickel foam, nickel mesh, and nickel felt.

[0014] In one embodiment, the substrate is cleaned in alcohol and acetone before being placed in the mixed solution, and the organic layer on the surface is removed by continuous ultrasonication.

[0015] In one embodiment, after the substrate is left to stand, the nickel foam covered by the sample is taken out and rinsed with deionized water and alcohol, and then placed in a vacuum oven and dried at 50-80° C. for 12 hours.

[0016] In one embodiment, the annealing requirement is to anneal at 200° C. for 2 hours in a muffle furnace.

[0017] The present invention also provides a high-efficiency water electrolyzer, characterized in that it comprises an electrolyte and an electrode made by any of the preparation methods described above, wherein the electrolyte is made by adding additional metal cations to a potassium hydroxide or sodium hydroxide solution.

[0018] In one embodiment, the metal cation is one of iron, molybdenum, cobalt and copper.

[0019] In one embodiment, the metal iron ion has a concentration of 1 mg L -1 of trivalent iron ions.

[0020] Compared with the prior art, the present invention has the following advantages or beneficial effects:

[0021] Compared with the traditional alkaline water electrode, the electrode prepared by the preparation method of the high-efficiency alkali hydrogen industrial electrode disclosed in the present invention has the following significant advantages: 1. It has a self-protection mechanism and can be competent for the harsh industrial electrolysis environment for a long time; 2. It has excellent catalytic activity, is stable and reliable, and is conducive to achieving high current density and reducing the energy consumption of hydrogen production; 3. It can give play to the synergy of the two electrodes and optimize the performance of the electrolyzer;

[0022] The electrode prepared by the method provided by the present invention is a nickel-molybdenum-iron trimetallic layered hydroxyl oxide bound to sulfate electrode. The electrode is a layered hydroxyl oxide similar to hydrotalcite. The interlayers of the traditional hydrotalcite structure are not bound to other components, or are bound to easily inactivated components such as carbonate. The present invention improves the formula, introduces sulfate ions, and achieves successful binding of sulfate by adjusting the preparation process. The sulfate is located in the middle of the layered hydroxyl oxide, and the binding and adsorption sites are metal sites such as nickel, molybdenum, and iron. Such improvements adjust the atomic ratio between nickel, copper, and iron, thereby adjusting the electronic structure of the surface, improving the reaction kinetics, and achieving performance improvement. At the same time, the introduction of sulfate also helps to resist the erosion of other negatively charged groups and improves the stability of the electrode during long-term operation. DETAILED DESCRIPTION

[0023] 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.

[0024] Example

[0025] 1. The nickel foam was cleaned in alcohol and acetone, and the organic layer on the surface was removed by continuous ultrasonication.

[0026] 2. Add 5-20g Na 2 Mo 4 ·2H 2 O, 5-20g C 2 H 5 NS and 20-40 g FeSO 4 6H 2 O was dissolved in 1600 mL of deionized water, and stirred vigorously to fully dissolve. Then, the mixed solution and the cleaned nickel foam were mixed and allowed to stand for 24 hours, and then the nickel foam covered by the sample was taken out and thoroughly rinsed with deionized water and alcohol. The product was then placed in a vacuum oven and dried at 80°C for 12 hours, and then annealed at 200°C in a muffle furnace for 12 hours to obtain a material for an efficient alkali hydrogen industrial electrode.

[0027] Because a vertically distributed nanosheet stacking structure grows on the nickel foam substrate and the porous skeleton structure of the nickel foam is preserved, the active specific surface area is preferentially exposed, which is beneficial to electrolyte penetration and gas overflow. In addition, the active species are rooted and grown on the nickel substrate in situ, ensuring mechanical bonding and charge transfer at the interface, which helps to cope with the stringent requirements of solid-liquid-gas interface dynamics during high-power and high-current density operation.

[0028] The present invention also provides a high-efficiency water electrolyzer, comprising an electrolyte and an electrode prepared by the above-mentioned preparation method, wherein the electrolyte is prepared by adding additional metal cations to a potassium hydroxide solution, so that it has a more excellent large-current catalytic activity and a longer operating stability, and at the same time has a lower production cost and a lower unit hydrogen production energy consumption, and therefore has greater market competitiveness and higher practical application value;

[0029] Specifically, the electrolyte solution enables the alkaline water electrolyzer structure to operate stably under harsh industrial conditions: the regulation of adding additional metal cations in the traditional electrolyte environment, including the regulation of the type of cations and the regulation of the cation concentration.

[0030] (1) Regulation of cation species: Add the same concentration (0-10 mg L -1 ) different types of metal cations, including: for example, ferric ions (ferric nitrate (Fe(NO 3 ) 3 9H 2 O) provides an iron source), divalent copper ions (copper sulfate (CuSO 4 ·5H 2 O) to provide a copper source), divalent cobalt ions (cobalt nitrate (Co(NO 3 ) 2 6H 2 O) provides a cobalt source) and hexavalent molybdenum ions (sodium molybdate (Na 2 MoO 4 9H 2 O) provides a molybdenum source), and the result obtained is that at the same concentration, the addition of iron ions has the best effect.

[0031] (2) Control of cation concentration: Adding the same type of trivalent iron ions at different concentrations to a conventional industrial electrolysis environment (30 wt% KOH solution) included: 0.5 mg L -1 , 1mg L -1 , 2mg L -1 , 5mg L -1 The result is 1mg L -1 Concentration works best.

[0032] Refer to the contents of Table 1 and Table 2: The high-efficiency water electrolyzer provided by the present invention shows significantly superior activity and stability compared with the electrolyzer operated in a traditional industrial environment, and can achieve 5000A / m at a voltage of 1.8V. 2 The hydrolyzer can produce a large current density of 5000A / m in a strong alkaline environment of 6M KOH.2 The high current density can run stably for more than 2000 hours, which is enough to adapt to the industrial strong alkali, high temperature and high power operating environment; its DC unit power consumption is 4.0kW·h / Nm 3 , the efficiency is superior to the current mainstream hydrolyzer (≥4.3kW·h / Nm 3 ), and the electrode manufacturing cost is low and the electrode cost is lower (~500￥ / m 2 ), has significant market competitiveness and application value.

[0033] Table 1: Polarization

[0034] <![CDATA[Magnetic density (A / m 2 )]]> Potential (V) 3000 1.7 4000 1.75 5000 1.8

[0035] Table 2: Stability

[0036] Time (h) 0 400 800 1200 1600 2000 2400 3000 <![CDATA[Magnetic density (A / m 2 )]]> 5000 5000 5000 5000 5000 5000 5000 5000 Potential (V) 1.80 1.80 1.80 1.80 1.80 1.81 1.81 1.81

[0037] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention.

[0038] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-efficiency alkali-hydrogen industrial electrode, characterized in that: The following steps are involved: Step 1: dissolve 5-20 g of a molybdenum-containing metal salt, 5-20 g of a sulfur-containing reagent, and 20-40 g of an iron-containing metal salt in 1600 mL of deionized water to prepare a mixed solution, and immerse the cleaned substrate in the mixed solution; Step 2: Let the mixed solution immersed in nickel foam stand at room temperature for 24-48 hours, then take out the sample, rinse it and vacuum dry it for 12-48 hours, and then anneal it at 25-300°C for 0-12 hours to obtain the high-efficiency alkali hydrogen industrial electrode.

2. The method for preparing a high-efficiency alkali-hydrogen industrial electrode according to claim 1, characterized in that: The molybdenum-containing metal salt is one of sodium molybdate and ammonium molybdate; The sulfur-containing reagent is one of thioacetamide and thiourea; The iron-containing metal salt is one of ferrous sulfate and ferric nitrate.

3. The method for preparing a high-efficiency alkali-hydrogen industrial electrode according to claim 1, characterized in that: The substrate is one of nickel foam, nickel mesh and nickel felt.

4. The method for preparing a high-efficiency alkali-hydrogen industrial electrode according to claim 1, characterized in that: The substrate is cleaned in alcohol and acetone before being placed in the mixed solution, and the organic layer on the surface is removed by continuous ultrasonication.

5. The method for preparing a high-efficiency alkali-hydrogen industrial electrode according to claim 1, characterized in that: After the substrate was left to stand, the nickel foam covered by the sample was taken out and rinsed with deionized water and alcohol, and then placed in a vacuum oven and dried at 50-80° C. for 12 hours.

6. The method for preparing a high-efficiency alkali-hydrogen industrial electrode according to claim 5, characterized in that: The annealing requirement is to anneal at 200° C. for 2 h in a muffle furnace.

7. A high-efficiency water electrolyzer, characterized in that: The invention comprises an electrolyte and an electrode prepared by the preparation method according to any one of claims 1 to 6, wherein the electrolyte is prepared by adding additional metal cations into a potassium hydroxide or sodium hydroxide solution.

8. A high-efficiency water electrolyzer according to claim 7, characterized in that: The metal cation is one of iron, molybdenum, cobalt and copper.

9. A high-efficiency water electrolyzer according to claim 8, characterized in that: The concentration of the metallic iron ion is 1 mg L -1 of trivalent iron ions.