WO2017084589A1 - Method and device for producing hydrogen by electrolyzing water through two-step method based on three-electrode system - Google Patents

Abstract

A method and device for producing hydrogen by electrolyzing water through a two-step method based on a three-electrode system. An electrolytic tank of the device comprises a hydrogen evolution catalytic electrode, an oxygen evolution catalytic electrode, and a hydroxide nickel electrode. The method comprises: water molecules are electrochemically reduced into hydrogen on the surface of a hydrogen evolution catalytic electrode, and meanwhile, an Ni(OH)₂ electrode is electrochemically oxidized into an NiOOH electrode, during the process, electrons flowing from the Ni(OH)₂ electrode to the hydrogen evolution catalytic electrode through an external circuit; and then, the NiOOH electrode is electrochemically reduced into the Ni(OH)₂ electrode, and meanwhile, hydroxyl ions are electrochemically oxidized into oxygen on the surface of an oxygen evolution catalytic electrode, during the process, the electrons flowing from the oxygen evolution catalytic electrode to the NiOOH electrode through an external circuit. The device and the method effectively divide hydrogen production and oxygen production steps happening at the same time in common water electrolyzation, and the electrolytic device can prepare high-purity hydrogen under the condition of not adopting any diaphragm due to complete separation of the hydrogen production and oxygen production steps, thereby further reducing the cost of producing the hydrogen by electrolyzing water.

Description

[Invention name established by ISA according to Rule 37.2] Method and apparatus for hydrogen production by electrolysis of water based on three-electrode system Technical field

The invention belongs to the technical field of electrolyzed water, and in particular relates to a novel method and device for hydrogen production by electrolysis of water in a two-step method based on a three-electrode system.

Background technique

Energy is an important material basis for developing the national economy and improving the quality of people's lives. It is an important constraint that directly affects economic development and is also one of the foundations of national strategic security guarantees. With the advent of the new century, the needs of human society for the quantity and quality of energy will be more and more high. However, due to endless exploitation and excavation, the energy resources for human survival are decreasing, and as the main energy source. The reserves of oil and coal are also drying up. At the same time, the traditional energy structure and a large amount of energy consumption have caused serious pollution to the human living environment. Humans call for clean energy to replace traditional energy sources. In order to solve the growing contradiction between economic development and energy shortage and environmental pollution, it has become a very urgent task to develop clean, efficient and sustainable new energy power technologies. The development of clean and efficient use of renewable energy and energy will be an important practical issue facing the international community today and will be of great significance to the sustainable development of the entire world economy. Hydrogen energy has received worldwide attention as an efficient, clean and ideal secondary energy source. Large-scale, low-cost production of hydrogen is one of the important links in the development and utilization of hydrogen energy.

Electrolytic water preparation of hydrogen is relatively simple, the technology is relatively mature, and the hydrogen production process is not polluted, which is an important means to achieve large-scale production of hydrogen. In the current hydrogen production industry, alkaline water electrolysis technology is industrialized early, the technology is mature, and the equipment cost is low. Therefore, alkaline water electrolysis plays a dominant role in the water electrolysis industry. However, because of its high energy consumption, it limits its wide application. More importantly, the conventional electrolyzed water technology generates hydrogen and oxygen at the same time as the anode and cathode in the electrode process, which will easily lead to the mixing of hydrogen and oxygen, resulting in impure gas production, and subsequent purification will be greatly increased. Large preparation costs. The use of an ion-selective membrane to separate the hydrogen produced by the hydrogen evolution catalytic electrode and the oxygen produced by the oxygen evolution catalytic electrode is an effective solution, but the use of ion-selective membranes also greatly increases the cost. In addition, due to the different kinetic processes of electrochemical hydrogen evolution and oxygen evolution, the hydrogen production rate and oxygen production rate are different. When the pressure on both sides of the ion selective membrane is different, the membrane loss is also very serious, which further increases the cost. . In addition, the selective ion exchange membrane further increases the internal resistance of the electrolytic cell and increases energy consumption. At present, the mainstream work is to improve or prepare a new type of diaphragm, in order to reduce the internal resistance, while taking into account the hydrophilicity, ion permeability and the ability to completely separate hydrogen and oxygen. Although many new membranes have been explored, the effects are still not very significant.

Summary of the invention

It is an object of the present invention to provide a method and apparatus for hydrogen production by electrolysis of water in a two-step process based on a three-electrode system without a membrane.

The invention provides a two-step method for electrolyzing water to produce hydrogen by a three-electrode system, wherein the electrolysis cell comprises three electrodes: a hydrogen evolution catalytic electrode which catalyzes the generation of hydrogen by electrolyzing water, and has oxygen for electrolyzing water. Catalytic oxygen evolution catalytic electrode and nickel hydroxide (Ni(OH) ₂ ) electrode.

In the hydrogen production step, the cathode is connected to the hydrogen evolution catalytic electrode, and the anode is connected to the nickel hydroxide electrode; in the oxygen production step, the cathode is connected to the nickel hydroxide electrode, and the anode is connected to the oxygen evolution catalytic electrode.

The method for the two-step method for electrolyzing water to produce hydrogen based on the three-electrode system provided by the invention has the following specific steps:

(1) Hydrogen production step (ie, step of generating hydrogen from electrolyzed water):

The water molecule is electrochemically reduced to hydrogen on the surface of the hydrogen evolution catalytic electrode as a cathode, that is, H ₂ O+e ^- → 1/2H ₂ + OH ^- ; and the Ni(OH) ₂ electrode as an anode is electrochemically oxidized to a NiOOH electrode. , that is, Ni(OH) ₂ + OH ^- -e ^- → NiOOH + H ₂ O, in which electrons flow from the Ni(OH) ₂ electrode to the hydrogen evolution catalytic electrode through an external circuit;

(2) Oxygen production step (ie, step of generating oxygen from electrolyzed water):

The NiOOH electrode as a cathode is electrochemically reduced to a Ni(OH) ₂ electrode, that is, NiOOH + H ₂ O + e ^- → Ni(OH) ₂ + OH ^- ; and the hydroxide ion is on the surface of the oxygen evolution catalytic electrode as an anode. It is electrochemically oxidized to oxygen, that is, 2OH ^- -2e ^- → 1/2O ₂ + H ₂ O; in this process, electrons flow from the oxygen evolution catalytic electrode to the NiOOH electrode through the external circuit.

The step (1) and the step (2) are alternately cycled.

The two steps are alternately cycled to realize the recycling of Ni(OH) ₂ , and at the same time, the electrolysis of hydrogen and electrolysis to produce oxygen at different times is effectively realized, and finally the hydrogen and oxygen mixing is effectively prevented, thereby achieving the purpose of high-purity hydrogen production. .

In the present invention, the hydrogen evolution catalytic electrode has a catalytic effect on hydrogen generation from electrolyzed water, and the catalytic electrode material is:

Based on a precious metal such as platinum (Pt) and its complex with carbon; or

a simple substance or a compound based on a transition metal such as Ni, Co, Fe, such as Ni, a Ni-Mo alloy, a Ni-Cr-Fe alloy, CoO, Co ₂ O ₃ , CoSe ₂ , FeP;

a compound based on Cu; or

W-based compounds such as WC, W ₂ C, WS ₂ ; or

Mo-based compounds such as MoS ₂ , MoB, Mo ₂ S; or

A compound such as C ₃ N ₄ .

In the present invention, the oxygen evolution catalytic electrode has a catalytic effect on the generation of oxygen by the electrolyzed water, and the catalytic electrode material is:

a compound based on a noble metal such as Ru, Ir, such as IrO _x , RuO ₂ ; or

Elemental or compound based on transition metals such as Ni, Co, Fe, Mn, such as NiFeO _x , NiCoO _x , CoFeO _x , CoO _x , NiCuO _x , NiO _x , SrNb _0.1 Co _0.7 Fe _0.2 O _3-x , MnO _x , CoMn ₂ O ₄ ; or

N, S, P, etc. doped carbon; or

A bioelectrochemical catalyst such as a laccase or the like.

In the present invention, the nickel hydroxide electrode is a nickel hydroxide electrode used in a conventional nickel-hydrogen battery, which is composed of an active material Ni(OH) ₂ and other additive components, and the added components are nickel powder, Co(OH) ₂ , carbon. One or more of powder and binder.

The binder is polytetrafluoroethylene.

The Ni(OH) ₂ active material and the additive component are pressed or coated on the metal current collector to form a Ni(OH) ₂ electrode by mixing into a film or slurry.

The metal current collector includes: a nickel mesh, a foamed nickel, a stainless steel mesh, a titanium mesh, or the like.

The electrolyte of the technique for electrolyzing water of the present invention must be an alkaline aqueous solution, and the alkaline aqueous solution is potassium hydroxide or sodium hydroxide.

The most notable feature of the electrolyzer designed in accordance with the present invention is that no separator is required to separate the hydrogen and oxygen produced by the electrolysis. The purity of the hydrogen and oxygen produced by the test showed that although there was no separator, hydrogen and oxygen did not mix.

The invention adopts a two-step constant current electrolysis method, and the electrolysis curve is shown in Fig. 2, which exhibits excellent electrolyzed water performance: repeating 20 times of two-step electrolysis hydrogen production and oxygen production, when 200 mA constant current electrolysis, The average hydrogen production voltage is about 1.6V, and the average oxygen production voltage is about 0.5V. Further, those skilled in the art can reasonably select an appropriate voltage range according to the selection of the electrode material and the electrolysis current. For example, the average voltage range of the hydrogen production may be 1.0-3.0 V, and the oxygen generation voltage range may be 0.2-1.5 V. . The invention is intended to be illustrative only and not to limit the scope of the invention.

Further, the electrolysis device of the present invention can use different driving voltages to generate hydrogen and oxygen, and in particular, sustainable energy sources such as solar energy and wind energy can be used to produce hydrogen more efficiently. For example, the hydrogen production or oxygen production step can be selectively performed according to the change of the sunlight intensity, and the utilization rate of the raw energy can be increased; or the hydrogen can be prepared by using excess electric energy at night, and the solar energy can be used to generate oxygen during the day. . In summary, the two-step electrolysis water hydrogen production method based on the three-electrode system proposed by the present invention is characterized in that hydrogen is electrolyzed by water and oxygen is electrolyzed in two steps. The nickel hydroxide (Ni(OH) ₂ ) electrode is electrochemically oxidized into a NiOOH electrode during the preparation of hydrogen in electrolyzed water; it is electrochemically reduced to Ni(OH) ₂ during the subsequent electrolysis of water to oxygen. . The nickel hydroxide (Ni(OH) ₂ ) electrode acts as a proton and electron buffer, separating the two steps of hydrogen production and oxygen production.

The apparatus for electrolyzing water to produce hydrogen by a two-step method based on a three-electrode system of the present invention comprises a hydrogen generating electrode pair and an oxygen generating electrode For example, the hydrogen generation electrode pair includes the hydrogen evolution catalytic electrode and a nickel hydroxide electrode, and the oxygen generation electrode pair includes the oxygen evolution catalytic electrode and a nickel hydroxide electrode.

In the hydrogen production electrode pair, the nickel hydroxide electrode is oxidized to a NiOOH electrode. In the oxygen generating electrode pair, the NiOOH electrode is electrochemically reduced to a Ni(OH) ₂ electrode.

The pair of hydrogen producing electrodes and the pair of oxygen generating electrodes are arranged to operate simultaneously or at different times, preferably at different times.

In other words, the cyclic electrochemical oxidation-reduction process of the nickel hydroxide electrode divides the conventional electrolyzed water process into two steps of continuous or separate, thereby realizing the preparation of high purity by separately preparing hydrogen and oxygen at different time periods. hydrogen. In addition, this method of segmentation also allows the device to eliminate the need for ion-selective membranes to separate hydrogen and oxygen, thus greatly reducing manufacturing costs.

DRAWINGS

Figure 1 shows the working diagram of a three-electrode system two-step electrolysis water electrolysis cell.

Figure 2 shows a schematic diagram of a three-electrode system two-step electrolysis water hydrogen/oxygen cycle.

detailed description

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined.

As used herein, when used in reference to a particular recited value, the term "about" means that the value can vary by no more than 1% from the recited value. For example, as used herein, the expression "about 100" includes all values between 99 and 101 and (eg, 99.1, 99.2, 99.3, 99.4, etc.).

As used herein, the terms "containing" or "including" may be open, semi-closed, and closed. In other words, the terms also include "consisting essentially of," or "consisting of."

As used herein, the terms "system," "device," and "system" have the same meaning and are used interchangeably.

As used herein, the terms "hydrogen production", "hydrogen production" have the same meaning and are used interchangeably.

The main advantages of the invention are:

1. In the electrolyzed water hydrogen producing apparatus of the present invention, hydrogen and oxygen are generated stepwise, without using a separator to separate hydrogen and oxygen generated by electrolysis.

2. The hydrogen and oxygen generated by the electrolyzed water device of the present invention are not mixed and have high safety.

3. The electrolyzed water device of the present invention can still perform high-efficiency electrolysis to generate hydrogen gas and oxygen under unstable voltage output conditions.

The invention is further illustrated below in conjunction with specific embodiments. It is to be understood that the examples are not intended to limit the scope of the invention. The experimental methods in the following examples which do not specify the specific conditions are usually in accordance with conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are by weight and parts by weight.

The experimental materials and reagents used in the following examples are available from commercially available sources unless otherwise specified.

Example 1:

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolyzer uses a platinum electrode, the catalytic electrode for electrolysis to generate oxygen is ruthenium oxide, and the nickel hydroxide electrode is commercially available with commercially available nickel hydroxide electrode. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol/L potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the platinum electrode, and the anode is connected to the nickel hydroxide electrode. The current is electrolyzed at 200 mA for 600 seconds, and the average voltage is about 1.6 V. Hydrogen is generated on the platinum electrode. Then, the cathode was connected to nickel hydroxide, and the anode was connected to the ruthenium oxide electrode, and the current was electrolyzed at a current of 200 mA until the voltage was raised to 1 V for 600 seconds, and the average voltage was 0.5 V. Oxygen was generated on the ruthenium oxide electrode. No gas is formed on the nickel hydroxide throughout the process. With this cycle 20 times, the curve is stable as shown in Figure 1, and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 2:

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolytic cell uses a platinum electrode, the catalytic electrode for electrolyzing oxygen is a mixed electrode of CoO and carbon, and the nickel hydroxide electrode is a commercially available nickel hydroxide electrode commercially available. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the platinum electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis time is 200 mA. The electrolysis time is 600 seconds, the average voltage is about 1.6 V, and hydrogen gas is generated on the platinum electrode. Then, the cathode is connected to nickel hydroxide, the anode is connected to the CoO and the carbon composite electrode, and the current is electrolyzed at a current of 200 mA until the voltage is raised to 1 V for 600 seconds. The average voltage is about 0.55 V, and oxygen is generated on the mixed electrode of CoO and carbon. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 3:

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolyzer uses a single layer of MoS ₂ and graphene composite electrodes, the catalytic electrode for electrolysis of oxygen is ruthenium oxide, and the nickel hydroxide electrode is commercially available as a commercially available nickel hydroxide electrode. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the MoS ₂ /graphene composite electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis time is 600 mA. The electrolysis time is 600 seconds, and the average voltage is about 1.65 V. Hydrogen is generated on the MoS ₂ /graphene composite electrode. Then, the cathode was connected to a nickel hydroxide electrode, and the anode was connected to a ruthenium oxide electrode, and the same was electrolyzed at a current of 200 mA until the voltage was raised to 1 V for 600 seconds. The average voltage was about 0.5 V, and oxygen was generated on the ruthenium oxide. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 4:

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolyzer uses a platinum electrode, the catalytic electrode for electrolysis to generate oxygen is ruthenium oxide, and the nickel hydroxide electrode is a composite electrode synthesized by in situ growth of nickel hydroxide and carbon nanotubes. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the platinum electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis is performed at 200 mA constant current for 600 seconds. The average voltage is about 1.62 V, and hydrogen gas is generated on the platinum electrode. Then, the cathode was connected to a nickel hydroxide electrode, and the anode was connected to a ruthenium oxide electrode, and the same was electrolyzed at a current of 200 mA until the voltage was raised to 1 V for 600 seconds. The average voltage was about 0.53 V, and oxygen was generated on the ruthenium oxide electrode. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 5:

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolytic cell uses a C ₃ N ₄ and graphene composite electrode, the catalytic electrode for electrolysis to generate oxygen is ruthenium oxide, and the nickel hydroxide electrode is commercially available for purchase of a commercial nickel hydroxide electrode. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the C ₃ N ₄ /graphene composite electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis time is 200 mA, the electrolysis time is 600 seconds, the average voltage is about 1.67 V, and the C ₃ N ₄ /graphene composite electrode Hydrogen is generated on it. Then, the cathode was connected to a nickel hydroxide electrode, and the anode was connected to a ruthenium oxide electrode, and the same was electrolyzed at a current of 200 mA until the voltage was raised to 1 V for 600 seconds. The average voltage was about 0.5 V, and oxygen was generated on the ruthenium oxide. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 6

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolyzer uses a single-layer MoS ₂ /graphene composite electrode, the catalytic electrode for electrolysis of oxygen is a CoO/carbon composite electrode, and the nickel hydroxide electrode is commercially available for commercial nickel hydroxide electrode. . The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the MoS ₂ /graphene composite electrode, the anode is connected to the nickel hydroxide electrode, and the 200 mA constant current electrolysis is performed. The electrolysis time is 600 seconds, the average voltage is about 1.65 V, and hydrogen gas is generated on the MoS ₂ /graphene composite electrode. Then, the cathode is connected to the nickel hydroxide electrode, the anode is connected to the CoO/carbon composite electrode, and the current is electrolyzed at a current of 200 mA until the voltage is raised to 1 V for about 600 seconds. The average voltage is about 0.55 V, and oxygen is generated on the CoO/carbon composite electrode. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 7

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolytic cell uses a platinum electrode, the catalytic electrode for electrolyzing oxygen is a mixed electrode of MnO _x and carbon, and the nickel hydroxide electrode is a commercially available nickel hydroxide electrode commercially available. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the platinum electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis time is 200 mA. The electrolysis time is 600 seconds, and the average voltage voltage is about 1.6 V. Hydrogen is generated on the platinum electrode. Then, the cathode is connected with nickel hydroxide, the anode is connected with MnO _x and the carbon composite electrode, and the same current is electrolyzed at 200 mA until the voltage is raised to 1 V for 600 seconds, the average voltage is about 0.58 V, and oxygen is generated on the mixed electrode of MnO _x and carbon. . No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Example 8

The catalytic electrode for electrolysis of hydrogen in the three-electrode electrolyzer uses a platinum electrode, the catalytic electrode for electrolyzing oxygen is a nitrogen-doped mesoporous carbon electrode, and the nickel hydroxide electrode is a commercially available nickel hydroxide electrode commercially available. The three electrodes have an area of 20 square centimeters. The electrolytic solution was electrolyzed using a 1 mol per liter potassium hydroxide solution using a constant current of 200 mA. First, the cathode is connected to the platinum electrode, the anode is connected to the nickel hydroxide electrode, and the electrolysis time is 200 mA. The electrolysis time is 600 seconds, and the average voltage voltage is about 1.6 V. Hydrogen is generated on the platinum electrode. Then, the cathode is connected with nickel hydroxide, the anode is connected with MnO _x and the carbon composite electrode, and the same current is electrolyzed at 200 mA until the voltage is raised to 1 V for 600 seconds, and the average voltage is about 0.58 V, which is formed on the nitrogen-doped mesoporous carbon electrode. oxygen. No gas is formed on the nickel hydroxide throughout the process. By this cycle 20 times, the cycle is stable and the gas is stably generated. Purity identification confirmed that no mixing of hydrogen and oxygen occurred.

Table 1. Comparison of 200 mA constant current electrolyzed water performance of electrolytic cells assembled with different electrodes.

All documents mentioned in the present application are hereby incorporated by reference in their entirety in their entireties in the the the the the the the the In addition, it should be understood that various modifications and changes may be made by those skilled in the art in the form of the appended claims.

Claims (15)

1. A two-step method for electrolyzing water to produce hydrogen based on a three-electrode system, characterized in that the electrolysis cell in the device comprises three electrodes: a hydrogen evolution catalytic electrode which catalyzes the generation of hydrogen by electrolyzing water, and generates oxygen for the electrolyzed water. Catalytic oxygen evolution catalytic electrode and nickel hydroxide (Ni(OH) ₂ ) electrode.
2. The apparatus according to claim 1, wherein said hydrogen evolution catalytic electrode has a catalytic effect on hydrogen generation from electrolyzed water, and said catalytic electrode material is:

   Based on metal platinum and its complex with carbon; or

   a simple substance or compound based on a transition metal of Ni, Co or Fe; or

   a compound based on Cu; or

   a compound based on W; or

   a compound based on Mo; or

   C ₃ N ₄ compound.
3. The apparatus according to claim 1, wherein said oxygen evolution catalytic electrode has a catalytic effect on the generation of oxygen by electrolyzed water, and the catalytic electrode material is:

   a compound based on Ru or Ir precious metal; or

   a simple substance or compound based on a transition metal of Ni, Co, Fe or Mn; or

   N, S, P doped carbon; or

   Bioelectrochemical catalyst.
4. The device of claim 2 wherein:

   The element or compound based on the transition metal of Ni, Co or Fe is Ni, Ni-Mo alloy, Ni-Cr-Fe alloy, CoO, Co ₂ O ₃ , CoSe ₂ or FeP;

   The W-based compound is WC, W ₂ C or WS ₂ ; or

   The Mo-based compound is MoS ₂ , MoB or Mo ₂ S.
5. The device of claim 3 wherein:

   The Ru or Ir precious metal-based compound is IrO _x or RuO ₂ ;

   The element or compound based on the transition metal of Ni, Co, Fe, Mn is NiFeO _x , NiCoO _x , CoFeO _x , CoO _x , NiCuO _x , NiO _x , SrNb _0.1 Co _0.7 Fe _0.2 O _3-x , MnO _x or CoMn ₂ O ₄ ;

   The bioelectrochemical catalyst is a compound such as laccase.
6. The apparatus according to claim 1, wherein said nickel hydroxide electrode is composed of a Ni(OH) ₂ active material and other additive components, said additive component being nickel powder, Co(OH) ₂ , carbon powder And one or more of the binders.
7. The device of claim 6 wherein said binder is polytetrafluoroethylene.
8. The apparatus according to claim 6, wherein said Ni(OH) ₂ active material and an additive component are pressed or coated on a metal current collector to form Ni(OH) by mixing into a film or slurry. ₂ electrode; the metal current collector comprises: nickel mesh, foamed nickel, stainless steel mesh or titanium mesh.
9. The apparatus according to claim 2, wherein said electrolyte for electrolyzing water is an alkaline aqueous solution, and said alkaline aqueous solution is potassium hydroxide or sodium hydroxide.
10. The device of claim 1 wherein the device is not included in the device.
11. A two-step method for electrolyzing water to produce hydrogen based on a three-electrode system, characterized in that the device comprises a pair of hydrogen producing electrodes and a pair of oxygen generating electrodes, the pair of hydrogen producing electrodes comprising the hydrogen evolution catalytic electrode and hydrogen peroxide A nickel electrode, the oxygen generating electrode pair comprising the oxygen evolution catalytic electrode and a nickel hydroxide electrode.
12. The apparatus according to claim 11, wherein said hydrogen generating electrode pair and said oxygen generating electrode pair are disposed to operate at different times.
13. The apparatus according to claim 11, wherein said hydrogen generating electrode pair has an operating voltage ranging from 1.0 to 3.0 volts.
14. The apparatus of claim 11 wherein said pair of oxygen generating electrodes has an operating voltage in the range of 0.2-1.5 volts.
15. The device of claim 11 wherein said device does not include a diaphragm device. 16. A method of two-step electrolysis of water to produce hydrogen based on the apparatus of any of claims 1 to 10, characterized in that the specific steps are as follows:

    (1) Hydrogen production steps:

    The water molecule is electrochemically reduced to hydrogen on the surface of the hydrogen evolution catalytic electrode as a cathode, that is, H ₂ O+e ^- → 1/2H ₂ + OH ^- ; and the Ni(OH) ₂ electrode as an anode is electrochemically oxidized to a NiOOH electrode. , that is, Ni(OH) ₂ + OH ^- -e ^- → NiOOH + H ₂ O, in which electrons flow from the Ni(OH) ₂ electrode to the hydrogen evolution catalytic electrode through an external circuit;

    (2) Oxygen production steps:

    The NiOOH electrode as a cathode is electrochemically reduced to a Ni(OH) ₂ electrode, that is, NiOOH + H ₂ O + e ^- → Ni(OH) ₂ + OH ^- ; and the hydroxide ion is on the surface of the oxygen evolution catalytic electrode as an anode. Electrochemical oxidation to oxygen, ie 2OH ^- -2e ^- → 1/2O ₂ + H ₂ O; in this process electrons flow from the oxygen evolution catalytic electrode through the external circuit to the NiOOH electrode;

    The step (1) and the step (2) are alternately cycled.

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