Two-step water electrolysis hydrogen production device and hydrogen production method based on three-electrode system

Abstract

The invention discloses a two-step water electrolysis hydrogen production device based on a three-electrode system and a hydrogen production method, and belongs to the technical field of water electrolysis, the two-step water electrolysis hydrogen production device comprises an oxygen evolution catalytic electrode, a hydrogen evolution catalytic electrode and a quinone polymer electrode HMND, the HMND is reduced in an acidic electrolyte to form a negatively charged intermediate, and the negatively charged intermediate and hydrogen ions are subjected to a coordination reaction to form HMND-2H; hydrogen ions are subjected to electrochemical reduction at the cathode oxygen evolution catalytic electrode to generate hydrogen, the HMND-2H electrode is subjected to electrochemical oxidation to form an HMND electrode, and electrons flow to the hydrogen evolution catalytic electrode from the HMND-2H electrode through an external circuit; the HMND electrode is electrochemically reduced into an HMND-2H electrode, water molecules are electrochemically oxidized into oxygen on the surface of the oxygen evolution catalytic electrode, and electrons flow to the HMND electrode from the oxygen evolution catalytic electrode through an external circuit; the hydrogen production process and the oxygen production process of the acidic electrolyzed water are carried out step by step, a diaphragm is not needed, and the method is low in toxicity, low in cost and environment-friendly.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis technology, specifically relating to a two-step water electrolysis hydrogen production device and method based on a three-electrode system. Background Technology

[0002] Hydrogen energy offers numerous significant advantages, such as high energy density and zero emissions. Through water electrolysis, environmentally friendly hydrogen gas can be produced, boasting an impressive energy density of 143 MJ / kg. -1 It is estimated that hydrogen produced through water electrolysis will dominate, accounting for as much as 70%. More importantly, this production process will be entirely driven by renewable energy, thus taking a solid step towards a green, low-carbon energy transition. Currently, the main bottleneck in the development of traditional alkaline water electrolysis (AWE) lies in the high overpotential problems associated with the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). It is particularly noteworthy that in alkaline electrolyzers, the HER reaction rate is at least two orders of magnitude lower than in acidic media, mainly due to the higher hydrogen content in acidic media. + This is due to the relatively high ion concentration. Furthermore, proton exchange membrane (PEM) electrolyzers have shown great potential among various water electrolysis technologies, thanks to their advantages such as high current density, high efficiency, high hydrogen purity, and compact battery structure. However, PEM-based water electrolysis technology also faces many challenges, such as the high cost associated with the proton exchange membrane, and the slow anolyte OER reaction in acidic media, as well as poor durability due to catalyst degradation. These factors severely restrict its practical application. Particularly noteworthy is the potential for gas cross-contamination under low current density conditions, which could trigger the formation of explosive H2 / O2 mixtures. Therefore, exploring efficient methods to develop membrane-free acidic water electrolysis technology is particularly urgent, enabling the independent release of H2 and O2 in time and space.

[0003] In view of the above factors, Cronin et al. first proposed to incorporate the polyoxometalate H3PMo 12 O 40The application of electron-coupled proton buffers (ECPBs) in stepwise water electrolysis provides a new approach to the temporal and spatial separation of H2 and O2. Meanwhile, inorganic redox mediators such as nickel hydroxide, silicotungstic acid, and sodium ferrocyanide have also been explored for decoupling processes in water electrolysis. Organic materials possess significant advantages in design flexibility, environmental friendliness, and cost-effectiveness, and theoretically should see wider application as ECPBs in water electrolysis decoupling; however, this has not been the case in practice. Quinone-based organic compounds have attracted widespread attention due to their high theoretical capacity, suitable redox potentials, and rapid reaction kinetics, primarily attributed to the enolization reaction at the carbonyl group. Therefore, research on carbonyl compounds suitable for membrane-free acidic water electrolysis is of crucial research value. Summary of the Invention

[0004] Technical problems to be solved:

[0005] To address the problems of slow anodic OER reaction and poor durability caused by catalyst degradation, which severely restrict its practical application, this invention provides a two-step water electrolysis hydrogen production device and method based on a three-electrode system. By utilizing quinone organic compounds as redox mediators, it achieves the independent generation of hydrogen and oxygen, while exhibiting outstanding advantages such as high hydrogen purity, excellent cost-effectiveness, and reduced energy consumption.

[0006] Technical solution:

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] A two-step water electrolysis hydrogen production device based on a three-electrode system includes an electrolyzer, in which a hydrogen evolution catalytic electrode for catalyzing the electrolysis of water to generate hydrogen, a quinone polymer electrode, and an oxygen evolution catalytic electrode for catalyzing the electrolysis of water to generate oxygen are arranged in parallel from left to right. The electrolyzer is filled with an acidic electrolyte. The electrolyzer is provided with a gas outlet, and a breather valve is provided at the gas outlet.

[0009] Furthermore, the electrode material of the hydrogen evolution catalytic electrode is: based on Pt, Pd, Au, or Ag and their complexes with carbon; or based on elemental or compound forms of transition metals such as Ni or Co; or

[0010] W-based compounds; or

[0011] Mo-based compounds;

[0012] The electrode material of the oxygen evolution catalytic electrode is:

[0013] Based on Ru, Ir, or Pt noble metals, alloys, and compounds; or N, S, or P doped carbon.

[0014] Furthermore, the quinone polymer electrode is made by mixing 60-80% active material HMND, 10-30% conductive agent, and the remainder binder by mass percentage, with a total amount of 100%. The electrode film is formed by rolling, and finally the electrode film is pressed onto the current collector to obtain the electrode.

[0015] Furthermore, the binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, water-soluble rubber, polyvinyl alcohol, sodium alginate, and polyacrylic acid, wherein the binder mass concentration is 20%; the conductive agent is one or more of Ketjen black, acetylene black, microcrystalline graphite, and conductive carbon black.

[0016] Furthermore, the current collector is one or more of the following: conductive graphite mesh, titanium mesh, nickel mesh, copper mesh, aluminum mesh, and stainless steel mesh.

[0017] Furthermore, the active material HMND is prepared by polymerization of 1,4-benzoquinone and 1,5-diaminonaphthalene. The specific preparation method is as follows: 10 mmol of 1,4-benzoquinone and 2 mmol of 1,5-diaminonaphthalene are taken in a molar ratio of 5:1 and ground in a mortar for 30 min. After mixing evenly, the mixture is dissolved in 50 mL of anhydrous ethanol and placed in a three-necked flask. After oil bath treatment at 70 °C and 600 r / min for 300 min, the product is cooled to room temperature and centrifuged three times with anhydrous ethanol as solvent. Then, it is centrifuged three times with ethyl acetate as solvent. After centrifugation, the product is placed in a vacuum drying oven and dried at 70 °C for 12 h to obtain the quinone polymer, i.e., the HMND material.

[0018] Furthermore, the acidic electrolyte is an acidic aqueous solution, wherein the acid is selected from one or a mixture of several of sulfuric acid, nitric acid, hydrochloric acid, perchloric acid, and glacial acetic acid.

[0019] Furthermore, the acidic electrolyte contains acid H. + The concentration is 0.5-2 mol / L.

[0020] A hydrogen production method based on a two-step water electrolysis device with a three-electrode system includes the following steps:

[0021] The first step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H +During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit.

[0022] The second step, the oxygen production step, involves connecting an oxygen evolution catalytic electrode to the anode and a quinone polymer electrode to the cathode: the HMND electrode, serving as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + During this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit.

[0023] Explanation of principle: This application achieves alternating cycles of hydrogen and oxygen production and realizes the recycling of quinone polymer HMND. It separately realizes the processes of hydrogen production and oxygen production by water electrolysis. Through timing control, the occurrence of hydrogen-oxygen mixing is effectively avoided, thereby ensuring the high purity of hydrogen production.

[0024] Beneficial effects:

[0025] This application provides a two-step water electrolysis hydrogen production device and method based on a three-electrode system, which has the following advantages compared with the prior art:

[0026] 1. This invention provides a type of quinone polymer electrode material for use in a two-step water electrolysis hydrogen production technology. The main active center of the quinone polymer is the carbonyl group. Through the interconversion of carbonyl and enol groups, a certain number of hydrogen ions can be inserted, and thus it can be used as ECPB in the stepwise water electrolysis.

[0027] 2. This invention measures the performance of the decoupling system under different applied currents (5-100mA) using the chronopotential method. The chronopotential curves demonstrate the excellent hydrogen and oxygen production stability of the system. The cyclicity of the stepwise electrolysis system for 600 consecutive cycles was studied under different electrolysis currents: cycles 1-50, electrolysis current 5mA, electrolysis time 4000s; cycles 51-100, electrolysis current 10mA, electrolysis time 2400s; cycles 101-200, electrolysis current 20mA, electrolysis time 1200s; cycles 201-350, electrolysis current 50mA, electrolysis time 800s; cycles 351-600, electrolysis current 100mA, electrolysis time 400s. Furthermore, the purity of the produced hydrogen and oxygen was tested, and the results showed that even without using any diaphragm, hydrogen and oxygen did not mix.

[0028] 3. The energy consumption of the two-step water electrolysis hydrogen production method based on a three-electrode system proposed in this invention is reduced from 6.139 kWh / m³ in the one-step method. -3 Reduced to 3.092 kWh m -3 Compared to the traditional one-step method, its energy consumption is significantly reduced;

[0029] 4. The most significant feature of the electrolyzer designed in this invention is that it utilizes HMND / HMND-2H in the acidic electrolyte as a redox intermediate to decompose water electrolysis into two steps. Compared with traditional acidic water electrolysis hydrogen production technology, this invention achieves high-purity hydrogen production by avoiding the simultaneous generation of hydrogen and oxygen. In addition, the time-separated production of hydrogen and oxygen is conducive to the flexible use of renewable energy. At night, wind power can be used to drive oxygen production, and during the day, solar energy can be used to electrolyze hydrogen.

[0030] 5. The biggest advantage of the two-step water electrolysis method designed in this invention is that it does not require a proton exchange membrane or other ion exchange membrane for electrolysis, which reduces the cost of electrolysis to a certain extent. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the operation of the two-step water electrolysis cell with a three-electrode system in this application;

[0032] Figure 2 The diagram shows the cyclic stability test results of the stepwise electrolysis system in this application.

[0033] Figure 3 The chronopotential curves for the electrolysis of hydrogen at a current of 1 mA for 12 hours according to this application are shown.

[0034] Figure 4 The chronopotential curve of oxygen electrolyzed at a current of 1 mA for 12 h according to this application;

[0035] Figure 5 The timing potential curve of the battery under a current of 5mA according to this application;

[0036] Figure 6 This is the battery's chronopotential curve under a current of 10mA according to this application;

[0037] Figure 7 This is the battery's timing potential curve under a current of 25mA according to this application;

[0038] Figure 8 This is the battery's chronopotential curve under a current of 50mA as described in this application;

[0039] Figure 9 This is the battery's timing potential curve under a current of 100mA according to this application;

[0040] Figure 10This is the battery's timing potential curve under a current of 200mA as described in this application;

[0041] Figure 11 This is the battery's timing potential curve under a current of 300mA as described in this application. Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0043] Example 1

[0044] This embodiment provides a two-step water electrolysis hydrogen production device based on a three-electrode system. The preparation method is as follows:

[0045] Step 1: Take 10 mmol of 1,4-benzoquinone and 2 mmol of 1,5-diaminonaphthalene, grind them in a mortar for 30 min, mix them evenly and dissolve them in 50 mL of anhydrous ethanol. Place the mixture in a three-necked flask and heat it in an oil bath at 70 °C and 600 r / min for 300 min. After cooling the product to room temperature, centrifuge it three times with anhydrous ethanol as the solvent, and then centrifuge it three times with ethyl acetate as the solvent. After centrifugation, place it in a vacuum drying oven and dry it at 70 °C for 12 h to obtain the quinone polymer, i.e., HMND material.

[0046] Step 2: Mix 60% of active material HMND, 30% of conductive agent Ketjen black, and 30% of binder by mass percentage, with a total amount of 100%. Grind the mixture in a mortar for 30 minutes. Roll the mixture into a thin and uniform film on a roller press. After drying, cut it into 1.5cm×2cm pieces to make an electrode film. Finally, press the electrode film onto a current collector titanium mesh to obtain a quinone polymer electrode.

[0047] Step 3: In the electrolytic cell, a hydrogen evolution catalytic electrode that catalyzes the electrolysis of water to generate hydrogen, a quinone polymer electrode, and an oxygen evolution catalytic electrode that catalyzes the electrolysis of water to generate oxygen are arranged in parallel from left to right. The electrolytic cell is filled with an acidic electrolyte. The electrolytic cell is provided with a gas outlet, and a breather valve is provided at the gas outlet.

[0048] Example 2

[0049] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0050] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0051] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 5 mA;

[0052] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0053] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed with a current of 5mA for 10800s, and hydrogen gas is generated on the platinum electrode.

[0054] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + During this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 5mA for 10800s, and oxygen is generated on the iridium oxide electrode.

[0055] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 5As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0056] Example 3

[0057] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0058] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0059] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 10 mA;

[0060] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0061] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed with a current of 10mA for 5400s, and hydrogen gas is generated on the platinum electrode.

[0062] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H +In this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 10mA for 5400s, and oxygen is generated on the iridium oxide electrode.

[0063] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 6 As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0064] Example 4

[0065] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0066] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0067] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 25 mA;

[0068] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0069] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed at a current of 25mA for 2300s, and hydrogen gas is generated on the platinum electrode.

[0070] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + In this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 25mA for 2300s, and oxygen is generated on the iridium oxide electrode.

[0071] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 7 As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0072] Example 5

[0073] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0074] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0075] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 50 mA;

[0076] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0077] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e -→H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed with a current of 50mA for 1200s, and hydrogen gas is generated on the platinum electrode.

[0078] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + In this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 50mA for 1200s, and oxygen is generated on the iridium oxide electrode.

[0079] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 8 As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0080] Example 6

[0081] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0082] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0083] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 100 mA;

[0084] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0085] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed with a current of 100mA for 500s, and hydrogen gas is generated on the platinum electrode.

[0086] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + In this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 100mA for 500s, and oxygen is generated on the iridium oxide electrode.

[0087] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 9 As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0088] Example 7

[0089] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0090] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode, i.e., 60% of the active material HMND, 30% of the conductive agent Ketjen Black, and 30% of the binder are mixed together, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixed slurry is rolled into a thin and uniform film on a roller press. After drying, it is cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0091] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 200 mA;

[0092] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0093] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed with a current of 200mA for 170s, and hydrogen gas is generated on the platinum electrode.

[0094] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + In this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 200mA for 170s, and oxygen is generated on the iridium oxide electrode.

[0095] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 10As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0096] Example 8

[0097] This embodiment provides a hydrogen production method based on a two-step water electrolysis hydrogen production device with a three-electrode system. The hydrogen production method is as follows:

[0098] Step 1: The two-step water electrolysis hydrogen production device based on the three-electrode system provided in Example 1 is used. The electrode material of the hydrogen evolution catalytic electrode is a platinum electrode, the electrode material of the oxygen evolution catalytic electrode is an iridium oxide electrode, and the quinone polymer electrode is a mixture of 60% active material HMND, 30% conductive agent Ketjen Black, and 30% binder, with a total amount of 100%. The mixture is ground in a mortar for 30 minutes. The mixture is rolled into a thin and uniform film on a roller press, dried, and cut into 1.5cm×2cm sizes to form electrode films. Finally, the electrode films are pressed onto the current collector titanium mesh to obtain the HMND electrode. The three electrodes are 1.5cm×2cm in size.

[0099] Step 2: Use a 1 mol / L sulfuric acid solution as the electrolyte and electrolyze using a constant current of 300 mA;

[0100] Step 3: The HMND electrode first undergoes a reduction process in a 1 mol / L sulfuric acid solution to form a negatively charged intermediate, which then undergoes a coordination reaction with hydrogen ions to form HMND-2H.

[0101] The fourth step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. Electrolysis is performed at a current of 300mA for 80s, and hydrogen gas is generated on the platinum electrode.

[0102] The fifth step, the oxygen production step, involves connecting the oxygen evolution catalytic electrode to the anode and the quinone polymer electrode to the cathode: the HMND electrode, acting as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H +During this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit. Electrolysis is performed at a current of 300mA for 80s, and oxygen is generated on the iridium oxide electrode.

[0103] Throughout the entire hydrogen and oxygen production process, no gas was generated on the HMND electrode, further confirming that hydrogen and oxygen did not mix during electrolysis. The curves are shown below. Figure 11 As shown, the electrolysis times for hydrogen production Step 1 and oxygen production Step 2 are equal, indicating that the coulombic efficiency of the electrolysis system is 100%.

[0104] The embodiments selected in the above materials are for ease of understanding and not for limiting the process method. Those skilled in the art can easily modify the process flow or transfer it to other cases without inventive change. If these modifications also fall under the category of similar claims or similar technology of this invention, then the intent of this invention also includes these modifications.

Claims

1. A two-step water electrolysis hydrogen production device based on a three-electrode system, characterized in that: The device includes an electrolytic cell, in which a hydrogen evolution catalytic electrode for catalyzing the electrolysis of water to generate hydrogen, a quinone polymer electrode, and an oxygen evolution catalytic electrode for catalyzing the electrolysis of water to generate oxygen are arranged in parallel from left to right. The electrolytic cell is filled with an acidic electrolyte. The electrolytic cell is provided with a gas outlet, and a breather valve is provided at the gas outlet.

2. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 1, characterized in that, The electrode material of the hydrogen evolution catalytic electrode is: Based on Pt, Pd, Au, or Ag and their complexes with carbon; or Based on elements or compounds of Ni and Co transition metals; or W-based compounds; or Mo-based compounds; The electrode material of the oxygen evolution catalytic electrode is: Based on Ru, Ir, or Pt noble metals, alloys, and compounds; or Carbon doped with N, S, and P.

3. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 1, characterized in that, The quinone polymer electrode is made by mixing 60-80% active material HMND, 10-30% conductive agent, and the remainder binder by mass percentage, with a total amount of 100%. The electrode film is formed by rolling and finally pressed onto the current collector to obtain the electrode.

4. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 3, characterized in that, The binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, water-soluble rubber, polyvinyl alcohol, sodium alginate, and polyacrylic acid, wherein the binder mass concentration is 20%; the conductive agent is one or more of Ketjen black, acetylene black, microcrystalline graphite, and conductive carbon black.

5. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 3, characterized in that, The current collector is one or more of the following: conductive graphite mesh, titanium mesh, nickel mesh, copper mesh, aluminum mesh, and stainless steel mesh.

6. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 3, characterized in that, The active material HMND is prepared by polymerization of 1,4-benzoquinone and 1,5-diaminonaphthalene. The specific preparation method is as follows: 10 mmol of 1,4-benzoquinone and 2 mmol of 1,5-diaminonaphthalene are taken in a molar ratio of 5:1 and ground in a mortar for 30 min. After mixing evenly, the mixture is dissolved in 50 mL of anhydrous ethanol and placed in a three-necked flask. After oil bath treatment at 70 °C and 600 r / min for 300 min, the product is cooled to room temperature and centrifuged three times with anhydrous ethanol as solvent. Then, it is centrifuged three times with ethyl acetate as solvent. After centrifugation, the product is placed in a vacuum drying oven and dried at 70 °C for 12 h to obtain the quinone polymer, i.e., HMND material.

7. The two-step water electrolysis hydrogen production device based on a three-electrode system according to claim 1, characterized in that, The acidic electrolyte is an acidic aqueous solution, wherein the acid is selected from one or a mixture of several of sulfuric acid, nitric acid, hydrochloric acid, perchloric acid, and glacial acetic acid.

8. The two-step water electrolysis hydrogen production apparatus based on a three-electrode system according to claim 7, characterized in that, The acidic electrolyte contains acid H. + The concentration is 0.5-2 mol / L.

9. The method for producing hydrogen using a two-step water electrolysis hydrogen production apparatus based on a three-electrode system according to any one of claims 1 to 8, characterized in that, The steps are as follows: The first step, hydrogen production, involves connecting a quinone polymer electrode to the anode and a hydrogen evolution catalytic electrode to the cathode. Hydrogen ions are electrochemically reduced to hydrogen gas (2H₂O) at the surface of the cathode's catalytic electrode. + +2e - →H2; simultaneously, the HMND-2H electrode, which serves as the anode, is electrochemically oxidized to the HMND electrode, i.e., HMND-2H–2e. - →HMND+2H + During this process, electrons flow from the HMND-2H electrode to the hydrogen evolution catalytic electrode through the external circuit. The second step, the oxygen production step, involves connecting an oxygen evolution catalytic electrode to the anode and a quinone polymer electrode to the cathode: the HMND electrode, serving as the cathode, is electrochemically reduced to the HMND-2H electrode, i.e., HMND+2H. + +2e - →HMND-2H; Simultaneously, water molecules are electrochemically oxidized into oxygen, i.e., H2O–2e, on the surface of the oxygen evolution catalytic electrode at the anode. - →1 / 2O2 + 2H + During this process, electrons flow from the oxygen evolution catalytic electrode to the HMND electrode through the external circuit.

Images