Method for preparing high-purity hydrogen and manganous-manganic oxide from membraneless electrolyzed water
Through the membrane-free electrolytic water preparation method, using manganese metal as anode to perform electrolysis in weakly acidic, neutral and weakly alkaline electrolyte, solving the problems of high-energy input and expensive membrane materials in the prior art, and achieving efficient preparation of high-purity hydrogen and trimanganese tetraoxide, which is suitable for industrial production.
Patent Information
- Application Number
- CN202411774477.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-05
- Publication Date
- 2025-03-28
AI Technical Summary
The existing electrolytic hydrogen production technology faces problems such as high energy input, scarce electrode materials and expensive proton or anion exchange membranes, which limits its large-scale application.
The preparation method of membrane-free electrolytic water is adopted, and the metal manganese is used as the anode to electrolyte in weakly acidic, neutral and weakly alkaline sulfate electrolyte. The manganese anode only undergoes an electrode oxidation reaction as the potential increases, and no oxygen precipitates, and high-purity hydrogen and trimanganese tetraoxide powder are obtained.
Obtaining high-purity hydrogen at high current density or at high voltages avoids oxygen generation and the use of expensive membrane materials, significantly reduces the anode overpotential, reduces the electrolytic water energy consumption, and the trimanganese tetraoxide oxidation products are easy to separate and recover.
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Figure CN119710729A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of hydrogen production by water electrolysis and the field of metallurgical electrochemical industry, and specifically is a method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis. Background Art
[0003] Using renewable electricity to drive water electrolysis technology is an effective way to produce green hydrogen. However, high energy input, scarce electrode materials and expensive proton or anion exchange membranes limit the large-scale application of this technology. In recent years, researchers have proposed many new electrochemical strategies to address these problems, which are currently divided into four categories. First, decoupling hydrogen production through redox mediators (including soluble and insoluble substances) can avoid the mixing of hydrogen and oxygen, and the overpotential of each step is very low, but the total energy consumption is high and the current density is limited. Second, coupling hydrogen production with electrochemical oxidation reactions (including organic and inorganic chemical conversions) has low energy consumption and effectively avoids the production of oxygen. At the same time, high-value-added chemicals can be obtained and / or pollutants can be removed, but chemical purification is difficult and the stability at high current density is greatly challenged. Third, electrochemical bipolar hydrogen production completely avoids the production of oxygen, achieves 200% Faradaic efficiency and low energy consumption, but it still faces great challenges in order to ensure the long-term stability of the anode and obtain high current density. Fourth, electrochemical hydrogen production coupled with power output fundamentally avoids the production of oxygen and produces electricity as a byproduct, but still faces great difficulties in achieving long-term electrode stability and high power density. These advanced electrochemical strategies show great potential in green hydrogen production, but they are still in the laboratory development stage and more efforts are needed to solve these problems in order to advance industrial applications. Summary of the invention
[0004] The purpose of the present invention is to provide a method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis. The method uses metal manganese as an anode. As the potential increases, the metal manganese anode only undergoes an electrode oxidation reaction without oxygen precipitation, and high-purity hydrogen can be obtained under high current density or high voltage. The anodic oxidation product is a high-value-added manganese tetraoxide powder, which is easy to separate and can be recycled as a raw material for use in the fields of metallurgy, electronics, catalysis, electrochemical energy storage materials, functional materials, coatings and paints, etc.
[0005] The purpose of the present invention is achieved through the following technical solutions: A method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the method comprising the following steps: Using manganese metal as anode and hydrogen evolution material as cathode, hydrogen is produced by membraneless water electrolysis in weakly acidic, neutral and weakly alkaline sulfate electrolytes; Under the electrolyte, when the applied potential is greater than the oxidation potential of metallic manganese, an electro-oxidation reaction occurs on the surface of the manganese anode to generate manganese tetraoxide powder without generating oxygen, and at the same time, hydrogen is precipitated at the cathode to obtain high-purity hydrogen; In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the metallic manganese in step (1) is industrial-grade metallic manganese with a manganese content of 90 to 99.999%.
[0006] The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, wherein the hydrogen-forming material in step (1) is a single metal of Pt, Ru, Ir, Ru, Rh, Fe, Co, Ni, Mo, W, Mn, Ti, V, Ag, Au, Re, a multi-metal alloy, and an oxide, hydroxide, phosphide, nitride, sulfide, carbide, selenide and telluride containing at least one metal.
[0007] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the pH value in step (1) is in the range of 5 to 12.
[0008] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the membrane in step (1) is a proton exchange membrane and an anion exchange membrane.
[0009] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the electrolyte in step (1) comprises sodium sulfate, potassium sulfate and an alkaline mixed solution of sodium sulfate, potassium hydroxide or sodium hydroxide.
[0010] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the electrolyte temperature in step (2) is 20 to 80°C.
[0011] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the applied potential in step (2) is -0.8 ~ 3.0 V vs . RHE.
[0012] In the method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the manganese tetraoxide in step (2) is in a crystalline phase.
[0013] The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, the membraneless water electrolysis hydrogen production device used in the hydrogen production method in step (3) comprises a membraneless water electrolysis hydrogen production device, a metal manganese anode, a hydrogen evolution cathode, a temperature measurement system, a stirring device, a hydrogen outlet, an electrolyte feed inlet and an electrolyte outlet.
[0014] The present invention has the following advantages and effects: 1. The present invention uses metallic manganese as the anode, thus avoiding the development of new anode materials.
[0015] 2. The metal manganese anode of the present invention only undergoes electrode oxidation reaction as the potential increases, without oxygen evolution, and high-purity hydrogen can be obtained under high current density or high voltage.
[0016] 3. The anode of the present invention does not generate oxygen, thus avoiding the use of expensive membrane materials.
[0017] 4. The present invention utilizes the advantage that the oxidation potential of metal manganese is much lower than the oxygen evolution potential, significantly reduces the anode overpotential, and reduces the energy consumption of water electrolysis.
[0018] 5. The high-purity hydrogen and manganese tetraoxide prepared by the present invention are suitable for water electrolysis in weakly acidic, neutral and weakly alkaline electrolytes, and cheap cathode electrode materials can be used.
[0019] 6. The anodized product of the present invention is a high value-added manganese oxide powder, which is easy to separate and can be recycled as a raw material for use in the fields of metallurgy, electronics, catalysis, electrochemical energy storage materials, functional materials, coatings and paints.
[0020] 7. The manganese metal source used in the present invention is rich in reserves and low in price, and no expensive diaphragm material is required. The production cost is low, the energy consumption is low, and it is easy to scale up, so it is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is the XRD pattern of the metal manganese sheet anode; Figure 2 This is the XRD pattern of the anodic oxidation product manganese tetraoxide; Figure 3 It is the linear voltammetric curve at different temperatures in Na2SO4 solution with pH=6.5; Figure 4 Gas production at 2.0 V vs. RHE; Figure 5 It is the linear voltammetric curve at different temperatures in Na2SO4+NaOH solution with pH=7.5; Figure 6 It is the linear voltammetric curve at different temperatures in Na2SO4+NaOH solution with pH=8.5; Figure 7 It is the linear voltammetric curve at different temperatures in Na2SO4+NaOH solution with pH=9.5; Figure 8 It is the linear voltammetric curve at different temperatures in Na2SO4+NaOH solution with pH=10.5; Fig. 9 Schematic diagram of a device for producing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis. DETAILED DESCRIPTION
[0022] The present invention is described in detail below in conjunction with specific implementation methods, but the protection scope of the present invention is not limited to the following embodiments. It should be noted that all other embodiments without outstanding creativity within the scope of the claims of the present invention and not listed in this specification should belong to the protection scope of the present invention. Example 1
[0023] The metal manganese sheet (manganese content is 98%) was used as the working electrode, the platinum sheet as the cathode, and the Ag / AgCl electrode as the reference electrode to conduct a membraneless water electrolysis hydrogen production test in a Na2SO4 electrolyte with a pH of 6.5. The phases of the metal manganese sheet and the anodic oxidation product are Figure 1 and Figure 2 Given in.
[0024] In the electrolyte at 20, 40, 60 and 80 °C, the voltage range is -0.7 ~ 2.0 V vs. The polarization curves were tested under RHE conditions with a scan rate of 0.002 V / s. The experimental results show that Figure 3 As shown, at 20, 40, 60, and 80 °C, the applied potential was 1.23 V. vs. At RHE, the current densities reached 74, 103, 139, and 143 mA / cm, respectively. 2 When the applied potential is as high as 2.0 V vs. At RHE, no oxygen is produced at the manganese anode. Figure 4 As shown, high purity hydrogen can be obtained at high current density. Example 2
[0025] A metal manganese sheet (manganese content of 98%) was used as a working electrode, a platinum sheet was used as a cathode, and an Ag / AgCl electrode was used as a reference electrode to conduct a membraneless water electrolysis hydrogen production test in a Na2SO4 and sodium hydroxide solution at pH = 7.5. The metal manganese sheet and the anodic oxidation product were the same as in Example 1.
[0026] In the electrolyte at 20, 40, 60 and 80 °C, the voltage range is -0.7 ~ 2.0 V vs. The polarization curves were tested under RHE conditions with a scan rate of 0.002 V / s. The experimental results show that Figure 5 As shown, at 20, 40, 60, and 80 °C, when the applied potential is 1.23 V vs . At RHE, the current density at each temperature reached 68, 97, 134 and 140 mA / cm 2 When the applied potential is as high as 2.0 V vs. During RHE, the manganese anode still produces no oxygen, achieving high-purity hydrogen at high current density. Example 3
[0027] A metal manganese sheet (manganese content of 98%) was used as a working electrode, a platinum sheet was used as a cathode, and a Hg / HgO electrode was used as a reference electrode to conduct a membraneless water electrolysis hydrogen production test in a Na2SO4 and sodium hydroxide solution at pH = 8.5. The metal manganese sheet and the anodic oxidation product were the same as in Example 1.
[0028] In the electrolyte at 20, 40, 60 and 80 °C, the voltage range is -0.7 ~ 2.0 V vs. The polarization curves were tested under RHE conditions with a scan rate of 0.002 V / s. The experimental results show that Figure 6 As shown, at 25, 40, 60, and 80 °C, when the applied potential is 1.23 V vs. When RHE is used, the current density at each temperature reaches 65, 114, 141 and 119 mA / cm 2 When the applied potential is as high as 2.0 V vs. During RHE, the manganese anode still produces no oxygen, achieving high-purity hydrogen at high current density. Example 4
[0029] A metal manganese sheet (manganese content of 98%) was used as a working electrode, a platinum sheet was used as a cathode, and a Hg / HgO electrode was used as a reference electrode to conduct a membraneless water electrolysis hydrogen production test in a Na2SO4 and sodium hydroxide solution at pH = 9.5. The metal manganese sheet and the anodic oxidation product were the same as in Example 1.
[0030] In the electrolyte at 20, 40, 60 and 80 °C, the voltage range is -0.7 ~ 2.0 V vs. The polarization curves were tested under RHE conditions with a scan rate of 0.002 V / s. The experimental results show that Figure 7 As shown, at 20, 40, 60, and 80 °C, when the applied potential is 1.23 V vs. When RHE is used, the current density at each temperature reaches 54, 82, 106 and 110 mA / cm 2 When the applied potential is as high as 2.0 V vs. During RHE, the manganese anode still produces no oxygen, achieving high-purity hydrogen at high current density. Example 5
[0031] A metal manganese sheet (manganese content of 98%) was used as a working electrode, a platinum sheet was used as a cathode, and a Hg / HgO electrode was used as a reference electrode to conduct a membraneless water electrolysis hydrogen production test in a Na2SO4 and sodium hydroxide solution at pH = 10.5. The metal manganese sheet and the anodic oxidation product were the same as in Example 1.
[0032] In the electrolyte at 20, 40, 60 and 80 °C, the voltage range is -0.7 ~ 2.0 V vs. The polarization curves were tested under RHE conditions with a scan rate of 0.002 V / s. The experimental results show that Figure 8 As shown, at 20, 40, 60, and 80 °C, when the applied potential is 1.23 V vs. When RHE is used, the current density at each temperature reaches 47, 87, 112 and 112 mA / cm 2 When the applied potential is as high as 2.0 V vs. During RHE, the manganese anode still produces no oxygen, achieving high-purity hydrogen at high current density. Example 6
[0033] The present invention relates to a device 1 for producing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, such as Fig. 9 As shown, it includes a metal manganese anode 2, a hydrogen evolution cathode 3, a temperature measurement system 4, a stirring device 5, a hydrogen outlet 6, an electrolyte feed port 7 and an electrolyte outlet 8. During the operation of the device, the electrolyte continuously enters the electrolytic cell, and under the applied voltage, the hydrogen evolution cathode continuously precipitates hydrogen, and the gas is continuously discharged and collected from the hydrogen outlet; at the same time, the metal manganese anode is continuously oxidized, and the generated manganese tetraoxide powder is continuously peeled off, dispersed into the electrolyte under strong stirring, and continuously discharged from the electrolyte outlet with the electrolyte.
[0034] The above disclosed embodiments of the invention are exemplary, and it cannot be understood that the scope of protection of the present invention is limited to the listed embodiments. These embodiments listed in this specification are to better illustrate the method and practical application effects of the present invention, so that people in the relevant technical field can better understand and use the present invention.
Claims
1. A method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis, characterized in that: The method comprises the following steps: (1) Using manganese metal as the anode and hydrogen evolution material as the cathode, hydrogen is produced by membraneless water electrolysis in weakly acidic, neutral and weakly alkaline sulfate electrolytes; (2) In the presence of an electrolyte, when the applied potential is greater than the oxidation potential of metallic manganese, an electro-oxidation reaction occurs on the surface of the manganese anode to generate manganese tetraoxide powder without producing oxygen. At the same time, hydrogen is precipitated at the cathode to obtain high-purity hydrogen.
2. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The metallic manganese in step (1) is industrial grade metallic manganese with a manganese content of 90 to 99.999%.
3. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The hydrogen-generating material in step (1) is a single metal of Pt, Ru, Ir, Ru, Rh, Fe, Co, Ni, Mo, W, Mn, Ti, V, Ag, Au, Re, a multi-metal alloy, and an oxide, hydroxide, phosphide, nitride, sulfide, carbide, selenide, and telluride containing at least one metal.
4. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The pH value in step (1) ranges from 5 to 12.
5. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The membranes in step (1) are proton exchange membranes and anion exchange membranes.
6. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The electrolyte in step (1) includes sodium sulfate, potassium sulfate and an alkaline mixed solution of sodium sulfate and potassium hydroxide or sodium hydroxide.
7. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The electrolyte temperature in step (2) is 20-80°C.
8. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The applied potential in step (2) is -0.8 ~ 3.0 V vs . RHE.
9. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The manganese tetraoxide in the step (2) is in a crystalline phase.
10. The method for preparing high-purity hydrogen and manganese tetraoxide by membraneless water electrolysis according to claim 1, characterized in that: The membraneless water electrolysis hydrogen production device used in the hydrogen production method in step (3) comprises a membraneless water electrolysis hydrogen production device (1), a metal manganese anode (2), a hydrogen evolution cathode (3), a temperature measurement system (4), a stirring device (5), a hydrogen outlet (6), an electrolyte feed inlet (7) and an electrolyte outlet (8).