Protium and deuterium separation coupling method for producing hydrogen by electrolyzing water
By using an iron-based catalyst in an alkaline environment to regulate the catalyst composition and electronic structure, the problems of low current density and low separation ratio in existing protium-deuterium separation technologies have been solved, achieving efficient protium-deuterium separation and heavy water byproduct, and reducing hydrogen production costs.
Patent Information
- Application Number
- CN202410971805.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2026-01-20
AI Technical Summary
Existing protium-deuterium separation technologies suffer from low current density and low separation ratio in acidic environments, making it difficult to achieve protium-deuterium separation at industrial current densities. Furthermore, they are energy-intensive and cannot meet the growing global demand for hydrogen isotopes.
Using an iron-based catalyst in an alkaline environment, the selective adsorption of protium and deuterium is improved by controlling the composition and electronic structure of the catalyst, following the Heyrovsky mechanism. Iron-containing materials are used as the hydrogen evolution reaction electrode, and seawater feed is combined to reduce costs.
It achieves a high protium-deuterium separation ratio, generally above 6, and can operate stably in alkaline environments, reducing the cost of hydrogen production from seawater electrolysis and producing heavy water as a byproduct.
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Figure CN121362985A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of electrolysis of water, and particularly relates to a method for electrolysis of water to produce hydrogen coupled with separation of protium and deuterium. BACKGROUND
[0002] The separation technology of protium and deuterium has wide application in the fields of nuclear industry, biological medicine, chemistry and energy, and has become an important part of national security. In order to meet the increasing demand for hydrogen isotopes worldwide, it is of great significance to develop a low-energy, high-yield and high-separation-ratio preparation technology for heavy water. The existing separation technology routes of protium and deuterium mainly include distillation method, gas-liquid phase catalytic exchange method and chemical exchange method, but these technology routes have problems such as upper limit of separation efficiency, high energy consumption, small processing flux and expensive supporting equipment.
[0003] At present, there are some reports on electrochemical separation catalysts of protium and deuterium in acidic environment, but there are problems such as low current density (such as less than 50 mA) and low separation ratio (such as less than 3), which are difficult to realize the separation of protium and deuterium under industrial current density. Under acidic conditions, metal sites can directly adsorb protium or deuterium, and the selectivity of protium and deuterium is poor, so it is difficult to further improve the separation ratio.
[0004] In order to solve at least one of the above problems, the present application is proposed. SUMMARY
[0005] The inventors found in the process of realizing the present application that under alkaline conditions, the catalysts usually follow the Heyrovsky mechanism, and the Heyrovsky mechanism has lower activity, so the active sites tend to adsorb and combine protium to generate hydrogen, thereby enriching deuterium in the liquid phase to achieve the purpose of isotope separation.
[0006] Therefore, it is of great significance to develop a catalyst following the Heyrovsky mechanism in alkaline environment for improving the separation of protium and deuterium coupled with hydrogen production by alkaline electrolysis of water. At the same time, the feed composition coupled with seawater can avoid excessive use of scarce fresh water resources, and can further reduce the cost of green hydrogen production by green electricity.
[0007] The present application found that in the alkaline electrolysis of water / seawater catalytic electrode, the iron-based catalyst containing iron element usually follows the Heyrovsky mechanism, and the selective adsorption of protium and deuterium is more significant. Therefore, the present application regulates the composition, electronic structure and coordination state of the catalyst based on iron-based, and realizes a high separation ratio of protium and deuterium.
[0008] The present application provides a method for electrolysis of water to produce hydrogen coupled with separation of protium and deuterium, which comprises: using a material containing an iron-based catalyst as a hydrogen evolution reaction electrode, wherein the iron-based catalyst contains iron element.
[0009] Preferably, the iron-based catalyst comprises one or more of: iron element, iron-containing compound, iron-containing mixture.
[0010] Preferably, the iron-based catalyst comprises one or more of:
[0011] iron element;
[0012] iron-based compound material;
[0013] catalyst modified based on the iron-based compound material;
[0014] iron-based alloy;
[0015] catalyst modified based on the iron-based alloy.
[0016] Preferably, the catalyst modified based on the iron-based compound material comprises a heterojunction catalyst modified based on the iron-based compound material.
[0017] Preferably, the catalyst modified based on the iron-based alloy comprises a heterojunction catalyst modified based on the iron-based alloy, a carbon-coated iron-based alloy catalyst.
[0018] Preferably, the method is also used to produce heavy water.
[0019] Preferably, the hydrogen evolution reaction electrode comprises: a conductive substrate for loading the iron-based catalyst.
[0020] The conductive substrate is selected from a metal or a carbon material.
[0021] Preferably, the electrolyte used in the method is pure water or seawater.
[0022] The electrolyte used in the method is alkaline water or alkaline seawater.
[0023] Preferably, the electrolyte used in the method contains 0.1-9 moles per liter of alkali metal hydroxide and 0-3 moles per liter of alkali metal halide. That is, the electrolyte can or can not contain alkali metal halide.
[0024] Preferably, the alkali metal hydroxide is selected from one or more of sodium hydroxide, potassium hydroxide or other alkaline substances. The alkali metal halide is selected from one or more of sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide.
[0025] Preferably, the iron-based compound material comprises one or more of: iron oxide material, iron sulfide material, iron phosphide material, iron selenide material, iron nitride material, iron hydroxide material;
[0026] The iron-based alloy comprises one or more of: carbon steel, molybdenum steel, manganese steel.
[0027] The iron-based compound material modified heterojunction catalyst includes one or more of the following: iron sulfide-chromium oxide material, iron phosphide-vanadium oxide material;
[0028] The iron-based alloy modified heterojunction catalyst includes the following: molybdenum steel-chromium oxide material, etc.
[0029] The iron-based alloy modified catalyst includes the following: iron-cobalt alloy coated with a carbon layer, etc.
[0030] The above-mentioned iron single substance, iron-containing compound, iron-containing mixture, iron-based alloy, iron-based compound, iron-based compound modified catalyst, etc. can be commercially available materials or prepared by existing technologies.
[0031] Preferably, the preparation method of the iron hydroxide material includes the following steps:
[0032] Iron salt, urea are added to water and ultrasonically dissolved, then transferred to an autoclave for hydrothermal reaction, and the obtained solid product is vacuum dried to obtain an iron hydroxide powder material.
[0033] Preferably, the preparation method of the iron oxide material includes the following steps:
[0034] Iron salt, urea are added to water and ultrasonically dissolved, then transferred to an autoclave for hydrothermal reaction, and the obtained solid product is vacuum dried to obtain an iron hydroxide powder material;
[0035] Then the obtained iron hydroxide powder material is calcined in a muffle furnace to obtain an iron oxide material.
[0036] The preparation method of the above-mentioned iron phosphide material includes the following steps:
[0037] The obtained iron hydroxide powder material is placed in a magnetic boat and placed downstream of a tube furnace, another magnetic boat is added with sodium hypophosphite and placed upstream of the tube furnace, and high-temperature calcination is performed under a nitrogen atmosphere, and the obtained solid product is vacuum dried to obtain an iron phosphide material.
[0038] Preferably, the iron salt is selected from one or more of the following: nitrate, sulfate, chloride.
[0039] The preparation method of the iron selenide material includes the following steps:
[0040] The obtained iron hydroxide powder material is placed in a magnetic boat and placed downstream of a tube furnace, another magnetic boat is added with selenium powder and placed upstream of the tube furnace, and high-temperature calcination is performed under a nitrogen atmosphere, and the obtained solid product is vacuum dried to obtain an iron selenide material.
[0041] The preparation method of the iron nitride material includes the following steps:
[0042] The obtained iron hydroxide powder material is placed in a magnetic boat and placed in a tube furnace for high-temperature calcination under a 75% nitrogen atmosphere. The obtained solid product is vacuum dried to obtain an iron nitride material.
[0043] The method for preparing the iron sulfide material comprises the following steps:
[0044] The iron hydroxide powder and thiourea are dissolved in ethanol, and after ultrasonic homogenization, the solution is transferred to an autoclave for hydrothermal reaction. The obtained solid product is vacuum dried to obtain an iron sulfide powder material.
[0045] When the hydrothermal reaction is performed, the conductive substrate is added to the autoclave to prepare an iron hydroxide material loaded on a conductive substrate, an iron oxide material loaded on a conductive substrate, an iron phosphide material loaded on a conductive substrate, an iron selenide material loaded on a conductive substrate, an iron nitride material loaded on a conductive substrate, and an iron sulfide material loaded on a conductive substrate.
[0046] The method for preparing the iron-based compound modified heterojunction catalyst comprises the following steps:
[0047] The method for preparing the iron sulfide-chromium oxide material comprises the following steps:
[0048] The iron sulfide material loaded on a conductive substrate is used as the working electrode, a stainless steel mesh is used as the counter electrode, a two-electrode system is used for constant current electrodeposition reaction, the electrolyte contains 1-100 millimoles per liter of chromium salt, the electrodeposition current is set to -5 to -100 milliamperes per square centimeter, and the electrodeposition time is set to 5-1600 seconds. Subsequently, the electrodeposited electrode is placed in a magnetic boat and placed in a tube furnace for calcination reaction under a nitrogen atmosphere at 250-400°C for 2-3 hours. After cooling, the obtained electrode is an iron sulfide-chromium oxide heterojunction material and can be directly used as an electrode.
[0049] The method for preparing the iron phosphide-vanadium oxide material comprises the following steps:
[0050] The electrodeposition electrolyte is replaced with an electrolyte containing vanadium salt, and the working electrode is replaced with the prepared iron phosphide electrode loaded on a conductive substrate, and the obtained electrode is an iron phosphide-vanadium oxide heterojunction electrode.
[0051] The method for preparing the molybdenum steel-chromium oxide comprises the following steps:
[0052] The cathode uses a molybdenum steel alloy electrode, the anode uses a stainless steel mesh, the electrolyte contains 50 millimoles per liter of chromium salt, the deposition current is -10 milliamperes per square centimeter, and the deposition time is 300 seconds, so that a molybdenum steel-chromium hydroxide heterogeneous junction electrode can be obtained. Subsequently, the electrode is placed in a magnetic boat and placed in a tube furnace, and a calcination reaction is carried out in a nitrogen atmosphere, the calcination temperature is 250-400 DEG C, and the calcination time is 2-3 hours. The obtained electrode is a molybdenum steel-chromium oxide heterogeneous junction electrode.
[0053] The second aspect of the application provides the use of the iron-based catalytic material of the first aspect for improving the hydrogen-deuterium separation ratio in the process of electrolyzing water to produce hydrogen.
[0054] Specifically, using the iron-based catalytic material described in the application as a water / sea water electrolysis cathode can achieve a higher hydrogen-deuterium separation ratio.
[0055] Preferably, the series of iron-based catalytic materials are loaded on a metal conductive substrate or a carbon material conductive substrate, or are used as an integrated catalyst for a cathode electrode of an electrocatalytic reaction.
[0056] In the application, the hydrogen-deuterium separation ratio refers to the ratio of the atomic ratio of D to H generated in the gas phase to the atomic ratio of D to H in the liquid phase, and the calculation formula is:
[0057]
[0058] Compared with the prior art, the application has the following beneficial effects:
[0059] 1. The application first discovers that using an iron element-containing substance as a hydrogen evolution reaction electrode for electrolyzing water / sea water to produce hydrogen coupled with hydrogen-deuterium separation to produce heavy water has excellent performance, and the separation ratio can generally reach more than 6. The iron-based catalyst is mainly in the heyrovsky mechanism in the hydrogen evolution reaction, has strong adsorption selectivity for hydrogen-deuterium, and is more likely to adsorb and combine with hydrogen having a lower energy, so as to enrich deuterium in the electrolyte while producing hydrogen and by-product heavy water.
[0060] 2. The application starts from the most basic iron oxide catalyst, further adjusts the electronic structure and coordination state by selecting the type of iron element-containing substance, optimizes the adsorption energy of the metal iron site and hydrogen isotopes (hydrogen and deuterium), and makes it more likely to adsorb and combine with hydrogen having a lower energy, so as to achieve the effect of isotope separation.
[0061] 3、The data of the examples show that iron-containing substances such as elemental iron, iron-containing compounds, and iron-containing mixtures generally have the effect of improving the hydrogen-deuterium separation ratio. These substances can be existing or self-made. The reason is that the metal iron sites are more inclined to combine with hydrogen in the hydrogen evolution process and with hydrogen having a lower binding energy, thereby enriching deuterium in the liquid phase to achieve the purpose of isotope separation. In particular, the iron selenide used for the electrolysis of water / seawater to produce hydrogen byproduct heavy water has a hydrogen-deuterium separation ratio of 9.5. The iron phosphide used for the electrolysis of water / seawater to produce hydrogen byproduct heavy water has a hydrogen-deuterium separation factor of up to 8.7, and can be stably operated for 500 hours at an industrial current density (0.4 amperes per square centimeter) in alkaline saturated brine. Therefore, the present application can further improve the hydrogen-deuterium separation ratio of the electrolysis method, produce heavy water as a byproduct while evolving hydrogen, and further reduce the cost of electrolysis of seawater to produce hydrogen BRIEF DESCRIPTION OF DRAWINGS
[0062] Figure 1 SEM image of the iron oxide nanoparticle catalyst prepared by the two-step method of Example 1.
[0063] Figure 2 Hydrogen evolution activity curve of the iron oxide electrode in alkaline seawater of Example 1.
[0064] Figure 3 Hydrogen-deuterium separation ratio of the iron oxide electrode in alkaline seawater of Example 1.
[0065] Figure 4 SEM image of the iron sulfide nanorod of Example 2.
[0066] Figure 5 XRD spectrum of the iron sulfide nanorod of Example 2.
[0067] Figure 6 Hydrogen evolution activity curve of the iron sulfide electrode in alkaline seawater of Example 2.
[0068] Figure 7 Hydrogen-deuterium separation ratio of the iron sulfide electrode in alkaline seawater of Example 2.
[0069] Figure 8 SEM image of the iron phosphide nanoparticle of Example 3.
[0070] Figure 9 XRD spectrum of the iron phosphide nanoparticle of Example 3.
[0071] Figure 10 Hydrogen evolution activity curve of the iron phosphide electrode in alkaline seawater of Example 3.
[0072] Figure 11 Hydrogen-deuterium separation ratio of the iron phosphide electrode in alkaline seawater of Example 3.
[0073] Figure 12Potentiostatic curve for the iron phosphide electrode of Example 3 in alkaline seawater.
[0074] Figure 13 Deuterium-hydrogen separation ratio for the iron selenide electrode of Example 4.
[0075] Figure 14 Deuterium-hydrogen separation ratio for the iron nitride electrode of Example 5.
[0076] Figure 15 Deuterium-hydrogen separation ratio for the iron hydroxide electrode of Example 6.
[0077] Figure 16 Deuterium-hydrogen separation ratio for the iron sulfide-chromium oxide electrode of Example 7.
[0078] Figure 17 Deuterium-hydrogen separation ratio for the iron phosphide-vanadium oxide electrode of Example 8.
[0079] Figure 18 Deuterium-hydrogen separation ratio for the elemental iron electrode of Example 9.
[0080] Figure 19 Deuterium-hydrogen separation ratio for the carbon steel of Example 10.
[0081] Figure 20 Deuterium-hydrogen separation ratio for the molybdenum steel of Example 11.
[0082] Figure 21 Deuterium-hydrogen separation ratio for the manganese steel of Example 12.
[0083] Figure 22 Deuterium-hydrogen separation ratio for the molybdenum steel-chromium oxide of Example 13.
[0084] Figure 23 Deuterium-hydrogen separation ratio for the molybdenum steel coated with carbon layer of Example 14.
[0085] Figure 24 Deuterium-hydrogen separation ratio for the nickel foam electrode of Comparative Example 1. DETAILED DESCRIPTION
[0086] The present application will now be described in connection with specific embodiments, but the embodiments of the present application are not limited thereto. The experimental methods in the examples, unless otherwise specified, were generally carried out according to conventional conditions and conditions described in manuals, or using general equipment, materials, reagents, etc. recommended by the manufacturers, and were commercially available, unless otherwise specified. The raw materials required in the following examples and comparative examples were commercially available.
[0087] Example 1 Preparation and characterization of iron oxide nanoparticles
[0088] Configuration of 36 ml solution: 0.2 g of ferric nitrate, 0.5 g of urea, dissolved in 36 ml of deionized water, the solution was transferred to a 50 ml water heating kettle, put into the oven, the reaction temperature was 120 degrees Celsius, the time was 8 hours. The obtained powder material was washed with water, ethanol for 3 times respectively, and dried in a vacuum drying box at 60 degrees Celsius for 8 hours, and the obtained product was a ferric hydroxide powder material.
[0089] The prepared ferric hydroxide powder material was transferred to a muffle furnace, the reaction temperature was 300 degrees Celsius, the reaction time was 2 hours, and the obtained powder material was calcined in air atmosphere, washed with water, ethanol for 3 times respectively, and dried in a vacuum drying box at 60 degrees Celsius for 8 hours, and the obtained product was an iron oxide nanoparticle material.
[0090] The above iron oxide nanoparticle material was subjected to scanning electron microscope test (SEM), and the results are shown in Figure 1 , which shows that the synthesized iron oxide nanoparticle catalyst has obvious particle morphology, uniform size distribution, and diameter of 10-50 nanometers.
[0091] Hydrogen evolution performance test of iron oxide nanoparticles
[0092] The hydrogen evolution performance of the iron oxide nanoparticle catalyst for electrolysis of seawater coupled with hydrogen and deuterium separation was tested by using a standard three-electrode system. The prepared iron oxide catalyst was loaded on a carbon paper substrate, the working area was 1*1 square centimeter, the loading was 5 milligrams per square centimeter, the amount of adhesive Nafion was 10 microliters, a mercury / mercury oxide electrode was selected as a reference electrode, a 1*1 square centimeter iron oxide catalyst loaded on carbon paper was used as a working electrode, and a nickel foam was used as a counter electrode. The electrolyte was a mixed simulated seawater solution of potassium hydroxide and sodium chloride, wherein the concentration of potassium hydroxide was 1.0 mol / L, and the concentration of sodium chloride was 0.5 mol / L. First, cyclic voltammetry scanning was performed at 100 mV / s in the range of 0 to -1 V vs RHE, and then linear scanning was performed at 5 mV / s in the range of 0 to -1 V vs RHE after the electrode reached a stable state. The obtained linear scan voltammogram is shown in Figure 2 . As can be seen from Figure 2 , the overpotential of the iron oxide nanoparticle catalyst in alkaline seawater at a current density of 10 mA / cm2 is 185 mV, which confirms its excellent hydrogen evolution reaction activity.
[0093] Hydrogen and deuterium separation ratio test of iron oxide nanoparticles
[0094] The prepared iron oxide catalyst is loaded on a carbon paper substrate with a working area of 1*1 square centimeter, a loading of 5 milligrams per square centimeter, and an adhesive Nafion dosage of 10 microliters, which is used for hydrogen-deuterium separation ratio testing. The test electrolyte is a mixed simulated seawater solution of potassium hydroxide and sodium chloride, wherein the potassium hydroxide concentration is 1.0 mole per liter, and the sodium chloride concentration is 0.5 mole per liter. The solution is composed of 50% ultrapure water and 50% heavy water (50% H2O + 50% D2O, H / D atomic ratio = 1:1). The hydrogen evolution reaction is carried out at a constant current density of 400 milliamperes per square centimeter. The generated hydrogen gas is collected and tested by gas chromatography to detect the contents of D2, HD, and H2 gases in the gas phase, and the hydrogen-deuterium separation ratio is calculated. Figure 3 The results show that the H atom content in the generated gas is 85.7%, the D atom content is only 14.3%, and the hydrogen-deuterium separation ratio is 6.0, which is higher than the currently reported hydrogen-deuterium separation ratio in acidic environments, confirming the excellent hydrogen-deuterium separation capability of the catalyst in alkaline seawater environments.
[0095] Example 2
[0096] Preparation and characterization of iron sulfide nanorods
[0097] A 36-milliliter solution is prepared: 0.3 grams of iron nitrate and 0.8 grams of urea are dissolved in 36 milliliters of deionized water. The solution is transferred to a 50-milliliter hydrothermal kettle, which is placed in an oven at a reaction temperature of 120 degrees Celsius for 8 hours. The obtained powder material is washed with water and ethanol three times each, and dried in a 60-degree Celsius vacuum drying box for 8 hours. The obtained product is a ferric hydroxide powder material. The prepared ferric hydroxide powder and 0.3 grams of thiourea are dissolved in 36 milliliters of ethanol, and then ultrasonically mixed. The solution is transferred to a 50-milliliter hydrothermal kettle, which is placed in an oven at a reaction temperature of 100 degrees Celsius for 8 hours. The obtained powder material is washed with water and ethanol three times each, and dried in a 60-degree Celsius vacuum drying box for 8 hours. The obtained product is a ferric sulfide powder material.
[0098] The above-mentioned ferric sulfide catalyst material is subjected to scanning electron microscope testing (SEM), and the results are shown in Figure 4 The results show that the morphology of the synthesized ferric sulfide catalyst is nanorod-shaped cubes, with a height of about 50-100 nanometers and a length-width of about 10-50 nanometers, Figure 5 The X-ray diffraction pattern of the prepared ferric sulfide nanorod-shaped catalyst (XRD) shows that the diffraction peaks are consistent with the standard cards of ferric sulfide and iron oxide, confirming the successful synthesis of ferric sulfide.
[0099] Hydrogen evolution performance test of ferric sulfide nanorods
[0100] The standard three-electrode system is used to test the hydrogen evolution performance of the iron sulfide nanorod catalyst for electrolysis of seawater coupled with hydrogen and deuterium separation. The prepared iron sulfide catalyst is loaded on a carbon paper substrate, with a working area of 1*1 square centimeters, a loading of 5 milligrams per square centimeter, and a binder Nafion dosage of 10 microliters. Mercury oxide is selected as the reference electrode, and the 1*1 square centimeter iron sulfide catalyst loaded on the carbon paper is used as the working electrode. The counter electrode uses a nickel foam, and the electrolyte uses a mixed simulated seawater solution of potassium hydroxide and sodium chloride, with a potassium hydroxide concentration of 1.0 moles per liter and a sodium chloride concentration of 0.5 moles per liter. First, a cyclic voltammetry scan is performed at a scan rate of 100 millivolts per second in the range of 0 to -1 V vs RHE until the electrode reaches a stable state. Then, a linear sweep is performed at a scan rate of 5 millivolts per second in the range of 0 to -1 V vs RHE. The resulting linear sweep voltammetry curve is shown in Figure 6 . As can be seen from Figure 6 , the overpotential of the iron sulfide electrode in alkaline seawater at a current density of 10 milliamperes per square centimeter is 221 millivolts.
[0101] Hydrogen and deuterium separation ratio test of iron sulfide nanorods
[0102] The prepared iron sulfide catalyst is loaded on a carbon paper substrate, with a working area of 1*1 square centimeters, a loading of 5 milligrams per square centimeter, and a binder Nafion dosage of 10 microliters. It is used for hydrogen and deuterium separation ratio testing, and the test electrolyte uses a mixed simulated seawater solution of potassium hydroxide and sodium chloride, with a potassium hydroxide concentration of 1.0 moles per liter and a sodium chloride concentration of 0.5 moles per liter. The solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction is carried out at a constant current density of 400 milliamperes per square centimeter, and the generated hydrogen gas is collected for gas chromatography testing to detect the contents of D2, HD, and H2 gases in the gas phase and calculate the hydrogen and deuterium separation ratio. Figure 7 The collected D2+HD and H2 gas contents show that the H atom accounts for 88.8% of the generated gas, and the D atom accounts for only 11.2%. The hydrogen and deuterium separation ratio is 7.9, which is higher than the currently reported hydrogen and deuterium separation ratio in acidic environments and higher than the hydrogen and deuterium separation ratio of iron oxide electrodes. This indicates that the sulfur treatment further adjusts the metal iron and hydrogen isotopes (hydrogen and deuterium) to make it easier to adsorb and combine with hydrogen isotopes with lower energy, thereby generating hydrogen and enriching deuterium in the liquid phase, achieving the effect of hydrogen and deuterium separation and byproduct heavy water production.
[0103] Example 3
[0104] Preparation and characterization of iron phosphide nanoparticles
[0105] Configuration of 36 ml solution: 0.3 g of ferric nitrate, 0.8 g of urea, dissolved in 36 ml of deionized water, the solution was transferred to a 50 ml water heating kettle, put into the oven, the reaction temperature was 120 degrees Celsius, the time was 8 hours. The obtained powder material was washed with water, ethanol 3 times respectively, and dried in a vacuum drying box at 60 degrees Celsius for 8 hours, and the obtained product was a ferric hydroxide powder material. The prepared ferric hydroxide powder was placed in a magnetic boat and placed downstream of the tube furnace, and another magnetic boat was taken, 0.5 g of sodium hypophosphite was weighed and placed upstream of the tube furnace, and calcined at 300 degrees Celsius under nitrogen protection atmosphere for two hours. The obtained powder material was washed with water, ethanol 3 times respectively, and dried in a vacuum drying box at 60 degrees Celsius for 8 hours, and the obtained product was a ferric phosphide powder material.
[0106] The above ferric phosphide catalyst material was tested by scanning electron microscope (SEM), and the results are shown in Figure 8 , which shows that the morphology of the synthesized ferric phosphide catalyst is nanoparticle, and the diameter is about 10-50 nanometers. Figure 9 The X-ray diffraction pattern (XRD) of the prepared ferric phosphide nanorod catalyst is shown in the figure, and the results show that the diffraction peak is consistent with the standard card of ferric phosphide and iron oxide, which confirms the successful synthesis of ferric phosphide.
[0107] Hydrogen evolution performance test of ferric phosphide nanoparticles
[0108] The hydrogen evolution performance of ferric phosphide nanoparticle catalyst for electrolysis of seawater coupled with hydrogen and deuterium separation was tested by using a standard three-electrode system. The prepared ferric phosphide catalyst was loaded on a carbon paper substrate, the working area was 1*1 square centimeter, the loading was 5 milligrams per square centimeter, the amount of adhesive Nafion was 10 microliters, mercury oxide was selected as the reference electrode, 1*1 square centimeter of ferric phosphide catalyst loaded on carbon paper was used as the working electrode, and nickel foam was used as the counter electrode. The electrolyte was a mixed simulated seawater solution of potassium hydroxide and sodium chloride, wherein the concentration of potassium hydroxide was 1.0 mol / L, and the concentration of sodium chloride was 0.5 mol / L. First, cyclic voltammetry scanning was carried out in the range of 0~-1V vs RHE at a scanning speed of 100 mV / s, and after the electrode reached a stable state, linear scanning was carried out in the range of 0~-1V vs RHE at a scanning speed of 5 mV / s. The obtained linear scanning voltammogram is shown in Figure 10 . As can be seen from Figure 10 , the overpotential of ferric phosphide nanoparticle catalyst in alkaline seawater at a current density of 10 mA / cm2 is 230 mV.
[0109] Test of hydrogen and deuterium separation ratio of ferric phosphide nanoparticles
[0110] The prepared iron phosphide catalyst is loaded on a carbon paper substrate with a working area of 1*1 square centimeter, a loading of 5 milligrams per square centimeter, and an adhesive Nafion dosage of 10 microliters, which is used for hydrogen-deuterium separation ratio testing. The test electrolyte uses a potassium hydroxide and sodium chloride mixed simulated seawater solution, wherein the potassium hydroxide concentration is 1.0 mole per liter, the sodium chloride concentration is 0.5 mole per liter, and the solution is composed of 50% super pure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction is carried out at a constant current density of 400 milliamperes per square centimeter, the generated hydrogen gas is collected, and gas chromatography testing is performed to detect the D2, HD, and H2 gas content in the gas phase, and the hydrogen-deuterium separation ratio is calculated. Figure 11 For the collected D2+HD and H2 gas content, the results show that the H atom accounts for 89.7% of the generated gas, the D atom accounts for only 10.3%, and the hydrogen-deuterium separation ratio is 8.7, which is higher than the currently reported hydrogen-deuterium separation ratio in acidic environments, and is also higher than the hydrogen-deuterium separation ratio of the prepared iron oxide and iron sulfide electrodes, confirming its excellent hydrogen-deuterium separation capability. This indicates that phosphide treatment further enhances the adsorption energy of metal iron sites with hydrogen, making it easier to combine with hydrogen with lower adsorption energy, generating hydrogen, thereby enriching deuterium in the liquid phase, achieving the effect of isotope separation. At the same time, it is found that the hydrogen evolution activity of the iron phosphide electrode with the highest hydrogen-deuterium separation ratio is the lowest, indicating that the lower the hydrogen evolution activity, the more the metal iron sites tend to combine with hydrogen with lower binding energy during the hydrogen evolution process, thereby enriching deuterium in the liquid phase to achieve the purpose of isotope separation.
[0111] Stability evaluation of iron phosphide nanoparticles for electrolytic seawater coupled hydrogen-deuterium separation
[0112] The stability of iron phosphide as a cathode electrode for electrolytic seawater coupled hydrogen-deuterium separation is evaluated using a standard two-electrode system. The cathode is a 1*1 square centimeter iron phosphide electrode, and the anode is a phosphorus nickel-cobalt-iron electrode. The electrolyte is a potassium hydroxide and sodium chloride mixed simulated seawater solution, wherein the potassium hydroxide concentration is 1.0 mole per liter, and the sodium chloride concentration is 0.5 mole per liter. The stability test is carried out at a constant current of 400 milliamperes per square centimeter, and the resulting constant current curve is shown in Figure 12 As can be seen from Figure 12 , the electrolytic seawater coupled hydrogen-deuterium separation using iron phosphide as the cathode can maintain long-term hydrogen evolution coupled hydrogen-deuterium separation stability, with a maximum time of about 500 hours. This indicates that iron phosphide electrodes can be used as electrode materials for electrolytic seawater coupled hydrogen-deuterium separation, producing hydrogen while producing heavy water, further reducing the cost of electrolytic seawater hydrogen production.
[0113] Example 4
[0114] Preparation of iron selenide and its hydrogen-deuterium separation ratio
[0115] Configuration 36 milliliter solution: iron nitrate 0.3 grams, urea 0.8 grams, dissolved in 36 milliliters of deionized water, the solution is transferred to a 50 milliliter hydrothermal kettle, 3*4 square centimeter cleaned foam nickel is placed in the hydrothermal kettle as the conductive substrate, put into the oven, the reaction temperature is 120 degrees Celsius, the time is 8 hours. The electrode material is washed with water, ethanol 3 times respectively, dried in a vacuum drying box at 60 degrees Celsius for 8 hours, the product obtained is iron hydroxide loaded on the foam nickel. The prepared iron hydroxide electrode is placed in a magnetic boat, placed in the downstream of the tube furnace, another magnetic boat adds 0.5 grams of selenium powder, placed in the upstream of the tube furnace, calcined at high temperature under nitrogen atmosphere, the reaction temperature is 300 degrees Celsius, the reaction temperature is 2 hours. The obtained solid product is vacuum dried, and the iron selenide electrode is obtained.
[0116] The iron selenide electrode is used for hydrogen and deuterium separation separation ratio test, the cathode uses the iron selenide electrode, the anode uses the foam nickel electrode, and the test electrolyte is 1 mole per liter sodium hydroxide solution. The solution is composed of 50 percent of ultrapure water and 50 percent of heavy water (H / D atomic ratio = 1:1). Hydrogen evolution reaction is carried out at a constant current density of 400 milliamperes per square centimeter, the generated hydrogen gas is collected, gas chromatography test is carried out, the contents of D2, HD and H2 in the gas phase are detected, and the hydrogen and deuterium separation ratio is calculated. Figure 13 The hydrogen and deuterium separation ratio of the iron selenide electrode is 9.5. The contents of D2+HD and H2 are collected, and the results show that the H atom accounts for 90.5% of the generated gas, and the D atom accounts for only 9.5%, and the hydrogen and deuterium separation ratio is 9.5. This proves that selenium topological transformation helps to further adjust the adsorption energy of iron sites to hydrogen and deuterium, reduces the adsorption energy of hydrogen, and achieves the purpose of enriching isotopes.
[0117] Example 5
[0118] Preparation of iron nitride and its hydrogen and deuterium separation ratio
[0119] Configuration 36 milliliter solution: iron nitrate 0.3 grams, urea 0.8 grams, dissolved in 36 milliliters of deionized water, the solution is transferred to a 50 milliliter hydrothermal kettle, 3*4 square centimeter cleaned foam nickel is placed in the hydrothermal kettle as the conductive substrate, put into the oven, the reaction temperature is 120 degrees Celsius, the time is 8 hours. The electrode material is washed with water, ethanol 3 times respectively, dried in a vacuum drying box at 60 degrees Celsius for 8 hours, the product obtained is iron hydroxide loaded on the foam nickel. The prepared iron hydroxide electrode is placed in a magnetic boat, placed in the downstream of the tube furnace, another magnetic boat adds 0.5 grams of selenium powder, placed in the upstream of the tube furnace, calcined at high temperature under nitrogen atmosphere, the reaction temperature is 300 degrees Celsius, the reaction temperature is 2 hours. The obtained solid product is vacuum dried, and the iron selenide electrode is obtained.
[0120] The iron nitride electrode is used for tritium-deuterium separation ratio test. The cathode uses an iron nitride electrode, the anode uses a nickel foam electrode, and the test electrolyte is a mixed simulated seawater solution of sodium hydroxide and sodium chloride, wherein the concentration of sodium hydroxide is 6 moles per liter, the concentration of sodium chloride is 3 moles per liter, and the solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction is carried out at a constant current density of 400 milliamps per square centimeter, the generated hydrogen gas is collected, gas chromatography test is carried out, the content of D2, HD and H2 gas in the gas phase is detected, and the tritium-deuterium separation ratio is calculated. Figure 14 The tritium-deuterium separation ratio of the iron nitride electrode is collected. The results show that the H atom accounts for 90.2% of the generated gas, the D atom accounts for only 9.8%, and the tritium-deuterium separation ratio is 9.2. This proves that nitrogen treatment compared with phosphorus sulfuration helps to adjust the adsorption energy of iron sites to tritium and deuterium, selectively adsorbs tritium rather than deuterium, and achieves the purpose of enriching isotopes.
[0121] Example 6 Preparation of iron hydroxide and tritium-deuterium separation ratio test
[0122] A 36-milliliter solution is configured: 0.2 grams of iron nitrate, 0.5 grams of urea, dissolved in 36 milliliters of deionized water, the solution is transferred to a 50-milliliter water heating kettle, placed in an oven, the reaction temperature is 120 degrees Celsius, and the time is 8 hours. The obtained powder material is washed with water and ethanol for 3 times respectively, and dried in a 60 degrees Celsius vacuum drying box for 8 hours. The obtained product is an iron hydroxide powder material.
[0123] The prepared iron hydroxide catalyst is loaded on a carbon paper substrate, the working area is 1*1 square centimeter, the loading is 5 milligrams per square centimeter, and the amount of adhesive Nafion is 10 microliters. It is used for tritium-deuterium separation ratio test, and the test electrolyte is a mixed solution of potassium hydroxide and sodium chloride, wherein the concentration of potassium hydroxide is 1.0 mole per liter, the concentration of sodium chloride is 0.5 mole per liter, and the solution is composed of 50% ultrapure water and 50% heavy water (50% H2O+50% D2O, H / D atomic ratio = 1:1). The hydrogen evolution reaction is carried out at a constant current density of 400 milliamps per square centimeter, the generated hydrogen gas is collected, gas chromatography test is carried out, the content of D2, HD and H2 gas in the gas phase is detected, and the tritium-deuterium separation ratio is calculated. Figure 15 The collected D2+HD and H2 gas content is 86.7%, and the D atom accounts for only 13.3% of the generated gas, and the tritium-deuterium separation ratio is 6.5, which confirms its excellent tritium-deuterium separation capacity.
[0124] Example 7 Preparation of iron-based heterojunction catalyst iron sulfide-chromium oxide and tritium-deuterium separation ratio test
[0125] Configuration 36 milliliter solution: iron nitrate 0.3 grams, urea 0.8 grams, dissolved in 36 milliliters of deionized water, the solution was transferred to a 50 milliliter hydrothermal kettle, 3*4 square centimeter cleaned foam nickel was placed in the hydrothermal kettle as the conductive substrate, placed in the oven, the reaction temperature was 120 degrees Celsius, the time was 8 hours. The electrode material was washed with water, ethanol 3 times respectively, dried in a vacuum drying box at 60 degrees Celsius for 8 hours, the product obtained was iron hydroxide loaded on the foam nickel. 0.3 grams of thiourea was dissolved in 36 milliliters of ethanol, ultrasonic was uniform, then the solution was transferred to a 50 milliliter hydrothermal kettle, the prepared iron hydroxide electrode was transferred to the hydrothermal kettle, placed in the oven, the reaction temperature was 100 degrees Celsius, the time was 8 hours. The electrode was washed with water, ethanol 3 times respectively, dried in a vacuum drying box at 60 degrees Celsius for 8 hours, the product obtained was iron sulfide electrode material loaded on the foam nickel. 20 millimoles per liter of metal chromium nitrate was added to the water, using the iron sulfide electrode as the working electrode, stainless steel mesh as the counter electrode, a two-electrode system was used to carry out constant current electrodeposition reaction, the constant current electrodeposition current density was set to-10 milliamperes per square centimeter, the electrodeposition time was set to 50 seconds. Subsequently, the electrode prepared by electrodeposition was placed in a magnetic boat and placed in a tube furnace, and a calcination reaction was carried out under a nitrogen atmosphere, the calcination temperature was 300 degrees Celsius, and the calcination time was 2 hours. The product obtained was an iron sulfide-chromium oxide heterojunction electrode material loaded on the foam nickel.
[0126] The iron sulfide-chromium oxide heterojunction electrode was used for hydrogen-deuterium separation separation ratio test, the cathode used the iron sulfide-chromium oxide heterojunction electrode, the anode used the foam nickel electrode, the test electrolyte was 0.1 moles per liter of potassium hydroxide solution, the solution was composed of 50 percent super pure water and 50 percent heavy water (H / D atomic ratio=1:1). Hydrogen evolution reaction was carried out at a constant current density of 400 milliamperes per square centimeter, the generated hydrogen gas was collected, gas chromatography test was carried out, the contents of D2, HD and H2 gases in the gas phase were detected, and the hydrogen-deuterium separation ratio was calculated. Figure 16 The hydrogen-deuterium separation ratio of the iron sulfide-chromium oxide heterojunction electrode. The results showed that the H atom accounted for 89.1% in the generated gas, the D atom accounted for only 10.9%, and the hydrogen-deuterium separation ratio was 8.2. This proved that the construction of the heterojunction structure helped to further adjust the adsorption energy of iron sites on hydrogen and deuterium, achieving the purpose of efficient enrichment of isotopes.
[0127] Example 8 Iron-based heterojunction catalyst iron phosphide- vanadium oxide preparation and hydrogen-deuterium separation ratio test
[0128] Configuration 36 milliliter solution: iron nitrate 0.3 grams, urea 0.8 grams, dissolved in 36 milliliters of deionized water, the solution was transferred to a 50 milliliter hydrothermal kettle, 3*4 square centimeter cleaned foam nickel was placed in the hydrothermal kettle as the conductive substrate, placed in the oven, the reaction temperature was 120 degrees Celsius, the time was 8 hours. The electrode material was washed with water, ethanol 3 times, dried in a vacuum drying oven at 60 degrees Celsius for 8 hours, the product was iron hydroxide loaded on the foam nickel.
[0129] The prepared iron hydroxide electrode loaded on the foam nickel was placed in a magnetic boat and placed downstream of the tube furnace. Another magnetic boat was prepared by weighing 0.5 grams of sodium hypophosphite and placing it upstream of the tube furnace. The mixture was calcined at 300 degrees Celsius under a nitrogen atmosphere for two hours. The resulting powder material was washed with water and ethanol three times and dried in a vacuum drying oven at 60 degrees Celsius for 8 hours. The product was an iron phosphide electrode loaded on the foam nickel. A two-electrode system was used for constant current electrodeposition reaction with the iron phosphide electrode as the working electrode and stainless steel mesh as the counter electrode. The constant current electrodeposition current density was set to -10 milliamperes per square centimeter and the electrodeposition time was set to 50 seconds. Subsequently, the electrode prepared by electrodeposition was placed in a magnetic boat and placed in a tube furnace for calcination under a nitrogen atmosphere. The calcination temperature was 300 degrees Celsius and the calcination time was 2 hours. The resulting product was an iron phosphide-vanadium oxide heterojunction electrode material loaded on the foam nickel.
[0130] The iron phosphide-vanadium oxide heterojunction electrode was used for hydrogen-deuterium separation ratio test. The cathode used the iron phosphide-vanadium oxide heterojunction electrode and the anode used the foam nickel electrode. The test electrolyte was a mixture of sodium hydroxide and potassium chloride with a sodium hydroxide concentration of 9 moles per liter and a potassium chloride concentration of 3 moles per liter. The solution was composed of 50% ultra-pure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 milliamperes per square centimeter. The generated hydrogen gas was collected and tested by gas chromatography to detect the content of D2, HD, and H2 gas in the gas phase. The hydrogen-deuterium separation ratio was calculated. Figure 17 The hydrogen-deuterium separation ratio of the iron phosphide-vanadium oxide heterojunction electrode was calculated. The results showed that the H atom accounted for 89.9% and the D atom accounted for only 10.1% in the generated gas, with a hydrogen-deuterium separation ratio of 8.9. This proved that the construction of the heterojunction structure helped to further adjust the adsorption energy of iron sites for hydrogen and deuterium, achieving the purpose of efficient enrichment of isotopes.
[0131] Example 9: Elemental iron hydrogen-deuterium separation ratio test
[0132] The commercially available elemental iron was used for the isotopic separation ratio test. The cathode electrode was iron electrode, the anode electrode was nickel foam electrode, the test electrolyte was 1 mol / L NaOH solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1 : 1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2, the generated hydrogen gas was collected, gas chromatography test was carried out, the content of D2, HD and H2 in the gas phase was detected, and the isotopic separation ratio was calculated. Figure 18 The isotopic separation ratio of elemental iron electrode. The content of D2+HD and H2 was collected, the results showed that the H atom accounted for 86.2% in the generated gas, the D atom accounted for only 13.8%, and the isotopic separation ratio was 6.2, which proved that the elemental iron electrode also had a high isotopic separation ratio.
[0133] Example 10 Iron-based alloy carbon steel isotopic separation ratio test
[0134] The commercially available carbon steel alloy (0.5% carbon content) electrode was used for the isotopic separation ratio test. The cathode electrode was carbon steel alloy electrode, the anode electrode was nickel foam electrode, the test electrolyte was 1 mol / L NaOH solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1 : 1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2, the generated hydrogen gas was collected, gas chromatography test was carried out, the content of D2, HD and H2 in the gas phase was detected, and the isotopic separation ratio was calculated. Figure 19 The isotopic separation ratio of carbon steel alloy electrode. The content of D2+HD and H2 was collected, the results showed that the H atom accounted for 86.7% in the generated gas, the D atom accounted for only 13.3%, and the isotopic separation ratio was 6.5, which proved that the iron-based alloy carbon steel electrode containing elemental iron also had a significant isotopic separation effect.
[0135] Example 11 Iron-based alloy molybdenum steel isotopic separation ratio test
[0136] The commercially available molybdenum steel alloy (0.3% molybdenum content) electrode was used for the isotopic separation ratio test. The cathode electrode was molybdenum steel alloy electrode, the anode electrode was nickel foam electrode, the test electrolyte was 1 mol / L NaOH solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1 : 1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2, the generated hydrogen gas was collected, gas chromatography test was carried out, the content of D2, HD and H2 in the gas phase was detected, and the isotopic separation ratio was calculated. Figure 20 The isotopic separation ratio of molybdenum steel alloy electrode. The content of D2+HD and H2 was collected, the results showed that the H atom accounted for 87.1% in the generated gas, the D atom accounted for only 12.9%, and the isotopic separation ratio was 6.8. This proved that the iron-based alloy molybdenum steel electrode containing elemental iron also had a significant isotopic separation effect
[0137] Example 12 Iron-based alloy manganese steel isotopic separation ratio test
[0138] The commercially available manganese steel alloy (containing 13% molybdenum) electrode was used for isotopic separation ratio test. The cathode used the manganese steel alloy electrode, and the anode used the nickel foam electrode. The test electrolyte was 1 mol / L sodium hydroxide solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2. The generated hydrogen gas was collected and tested by gas chromatography to detect the content of D2, HD and H2 in the gas phase, and the isotopic separation ratio was calculated. Figure 21 The isotopic separation ratio of the manganese steel alloy electrode was collected. The results showed that the H atom accounted for 87.3% of the generated gas, and the D atom accounted for only 12.7%. The isotopic separation ratio was 6.9. This proved that the iron-based alloy manganese steel electrode containing elemental iron also had a significant isotopic separation effect
[0139] Example 13 Molybdenum steel-chromium oxide isotopic separation ratio test
[0140] The cathode used the molybdenum steel alloy electrode (containing 0.3% molybdenum), and the anode used stainless steel mesh. The electrolyte contained 50 mmol / L chromium nitrate. The deposition current was -10 mA / cm2, and the deposition time was 300 seconds. A molybdenum steel-chromium hydroxide heterojunction electrode was obtained. Subsequently, the electrode was placed in a magnetic boat and put into a tube furnace to carry out calcination reaction under nitrogen atmosphere. The calcination temperature was 300°C, and the calcination time was 2 hours. The obtained electrode was a molybdenum steel-chromium hydroxide heterojunction electrode.
[0141] The molybdenum steel-chromium hydroxide heterojunction electrode was used for isotopic separation ratio test. The cathode used the molybdenum steel-chromium hydroxide heterojunction electrode, and the anode used the nickel foam electrode. The test electrolyte was 1 mol / L sodium hydroxide solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2. The generated hydrogen gas was collected and tested by gas chromatography to detect the content of D2, HD and H2 in the gas phase, and the isotopic separation ratio was calculated. Figure 22 The isotopic separation ratio of the molybdenum steel-chromium hydroxide heterojunction electrode was collected. The results showed that the H atom accounted for 87.8% of the generated gas, and the D atom accounted for only 12.2%. The isotopic separation ratio was 7.2. This proved that the construction of heterojunction structure based on commercial iron-based alloy electrode helped to adjust the adsorption energy of iron sites to hydrogen and deuterium, achieving the purpose of efficient enrichment of isotopes.
[0142] Example 14 Molybdenum steel alloy coated with carbon layer isotopic separation ratio test
[0143] The carbon-coated molybdenum steel alloy electrode (0.3% molybdenum) was used for the separation ratio test of hydrogen and deuterium. The cathode electrode was a carbon-coated molybdenum steel alloy electrode, and the anode electrode was a nickel foam electrode. The test electrolyte was 1 mol / L sodium hydroxide solution, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2, the generated hydrogen gas was collected, and gas chromatography test was performed to detect the content of D2, HD and H2 in the gas phase, and the hydrogen-deuterium separation ratio was calculated. Figure 23 The hydrogen-deuterium separation ratio of the carbon-coated molybdenum steel alloy electrode was collected. The results showed that the H atom accounted for 87.3% of the generated gas, and the D atom accounted for only 12.7%, and the hydrogen-deuterium separation ratio was 6.9. This proves that the carbon-coated molybdenum steel alloy electrode does not affect the adsorption energy of iron sites on hydrogen and deuterium, and also achieves the purpose of efficient enrichment of isotopes.
[0144] The hydrogen-deuterium separation ratio test of the nickel foam electrode of Comparative Example 1
[0145] The nickel foam electrode was used as the electrolytic seawater coupled hydrogen-deuterium separation cathode. The test electrolyte was a mixed solution of 1.0 mol / L potassium hydroxide and 0.5 mol / L sodium chloride, and the solution was composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2, the generated hydrogen gas was collected, and gas chromatography test was performed to detect the content of D2, HD and H2 in the gas phase, and the hydrogen-deuterium separation ratio was calculated. Figure 24 The hydrogen-deuterium separation ratio of the collected D2+HD and H2 gas was 3.5, which indicated that the hydrogen-deuterium separation capacity was poor. The applicant analyzed that this was due to the good electrolytic hydrogen evolution activity of the nickel-based catalyst, and the poor selectivity of hydrogen and deuterium, so it was difficult to selectively distinguish hydrogen and deuterium in the hydrogen evolution process, and the hydrogen-deuterium separation ratio was low.
[0146] Table 1 is the hydrogen-deuterium separation ratio of the iron-based catalyst and the foam nickel electrode, which shows that the iron-based catalyst described in the present application has more significant adsorption selectivity for hydrogen-deuterium than the foam nickel electrode. Based on the active site regulation strategy of the iron-based catalyst, the adsorption energy of metal iron and hydrogen isotopes (hydrogen and deuterium) is effectively adjusted, which makes it easier to combine with hydrogen having lower adsorption energy, generate hydrogen, thereby enriching deuterium in the liquid phase, and realizing hydrogen evolution while byproducting heavy water. When the prepared iron-based catalytic electrode is used for hydrogen evolution coupled with isotopic separation under the condition of water electrolysis / seawater electrolysis, it has a high separation factor. The data of the examples show that the hydrogen-deuterium separation factor of the iron selenide used for hydrogen production byproducting heavy water by water / seawater electrolysis can reach 9.5; the hydrogen-deuterium separation factor of the iron phosphide used for hydrogen production byproducting heavy water by water / seawater electrolysis can reach 8.7, and it can be stably operated for 500 hours at an industrial current density (0.4 ampere per square centimeter) in alkaline saturated brine. The present application can further improve the separation efficiency of hydrogen-deuterium separation by electrolysis, and further reduce the cost of hydrogen production by water / seawater electrolysis by byproducting heavy water.
[0147] Table 1 is the hydrogen-deuterium separation ratio of the iron-based catalyst and the foam nickel electrode, which shows that the iron-based catalyst described in the present application has more significant adsorption selectivity for hydrogen-deuterium than the foam nickel electrode. Based on the active site regulation strategy of the iron-based catalyst, the adsorption energy of metal iron and hydrogen isotopes (hydrogen and deuterium) is effectively adjusted, which makes it easier to combine with hydrogen having lower adsorption energy, generate hydrogen, thereby enriching deuterium in the liquid phase, and realizing hydrogen evolution while byproducting heavy water. When the prepared iron-based catalytic electrode is used for hydrogen evolution coupled with isotopic separation under the condition of water electrolysis / seawater electrolysis, it has a high separation factor. The data of the examples show that the hydrogen-deuterium separation factor of the iron selenide used for hydrogen production byproducting heavy water by water / seawater electrolysis can reach 9.5; the hydrogen-deuterium separation factor of the iron phosphide used for hydrogen production byproducting heavy water by water / seawater electrolysis can reach 8.7, and it can be stably operated for 500 hours at an industrial current density (0.4 ampere per square centimeter) in alkaline saturated brine. The present application can further improve the separation efficiency of hydrogen-deuterium separation by electrolysis, and further reduce the cost of hydrogen production by water / seawater electrolysis by byproducting heavy water.
[0148]
[0149]
Claims
1. A method for hydrogen production by electrolysis of water coupled with separation of protium and deuterium, characterized in that, The method comprises using a material containing an iron-based catalyst as a hydrogen evolution reaction electrode, the iron-based catalyst comprising an iron element.
2. The method of claim 1, wherein the method is characterized by, The iron-based catalyst comprises one or more of iron single substance, iron-containing compound, iron-containing mixture.
3. The method of claim 1, wherein the method is characterized by, The iron-based catalyst comprises one or more of the following materials: iron single substance; iron-based compound material; catalyst modified based on the iron-based compound material; iron-based alloy; catalyst modified based on the iron-based alloy.
4. The method of claim 3, wherein the method is characterized by, The catalyst modified based on the iron-based compound material comprises a heterojunction catalyst modified based on the iron-based compound material; The catalyst modified based on the iron-based alloy comprises a heterojunction catalyst modified based on the iron-based alloy, and a carbon-coated iron-based alloy catalyst.
5. The method of claim 3, wherein the method further comprises: The method is also used for producing heavy water.
6. The method of claim 3, wherein the method further comprises: The hydrogen evolution reaction electrode comprises a conductive substrate for loading the iron-based catalyst.
7. The method of claim 3, wherein the method further comprises: The electrolyte used in the method can be pure water or seawater; or the electrolyte used in the method contains alkali metal hydroxide and can also contain alkali metal halide salt, wherein the concentration of alkali metal hydroxide is 0.1-9 mol / L, and the concentration of alkali metal halide salt is 0-3 mol / L.
8. The method of claim 7, wherein the method further comprises: The alkali metal hydroxide is selected from one or more of sodium hydroxide and potassium hydroxide.
9. The method of claim 1, wherein the method further comprises: The iron-based compound material comprises one or more of iron oxide material, iron sulfide material, iron phosphide material, iron selenide material, iron nitride material, and iron hydroxide material; The iron-based alloy comprises one or more of carbon steel, molybdenum steel, and manganese steel; The heterojunction catalyst modified based on the iron-based compound material comprises one or more of iron sulfide-chromium oxide material and iron phosphide-vanadium oxide material; The catalyst modified based on the iron-based alloy comprises a carbon-coated molybdenum steel alloy; The heterojunction catalyst modified based on the iron-based alloy comprises molybdenum steel-chromium oxide material.
10. Use of an iron-based catalytic material for a cathode for electrolysis of water / seawater to produce hydrogen to improve the hydrogen-deuterium separation ratio in the process of electrolysis of water to produce hydrogen.