Electrolyte additive and electrolyte for improving separation ratio of protium and deuterium in electrolytic water coupling
By adding specific additives to the electrolyte and dynamically controlling the cathode hydrogen bond network, the problem of low protium-deuterium separation ratio under alkaline conditions was solved, achieving efficient protium-deuterium separation and heavy water byproduct, and reducing the cost of green hydrogen production.
Patent Information
- Application Number
- CN202410971804.X
- 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
In existing water electrolysis hydrogen production processes, the protium-deuterium separation ratio is low and the catalyst performance is poor under alkaline conditions, making it difficult to improve the protium-deuterium separation ratio without affecting hydrogen evolution activity.
By adding organic additives such as carboxyl groups, amine groups, and amides, or inorganic additives such as sodium salts, potassium salts, and lithium salts to the electrolyte, these additives adsorb and disrupt the hydrogen bond network on the cathode surface, dynamically controlling the hydrogen bond network, promoting protium-deuterium exchange and selective adsorption-desorption, and improving the protium-deuterium separation ratio.
While maintaining the catalyst's hydrogen evolution activity, the deuterium-proton separation ratio at the water electrolysis cathode was significantly improved from the original 5.4 to 11.3, achieving the production of green hydrogen while simultaneously producing heavy water as a byproduct, which has high economic and commercial value.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of electrolysis of water, and particularly relates to an electrolyte additive for improving the separation ratio of electrolysis of water coupled with hydrogen and deuterium separation. BACKGROUND
[0002] Direct electrolysis of water to produce hydrogen using renewable energy provides a sustainable strategy for green hydrogen production. For a long time, research on electrolysis of water to produce hydrogen has been focused on high-performance cathode catalysts, while the abundant deuterium resources in water have been largely ignored. If electrolysis of water / seawater to produce hydrogen coupled with hydrogen and deuterium separation can be used, not only can renewable energy be used to produce green hydrogen, but also heavy water can be produced as a byproduct, which will further reduce the cost of green hydrogen.
[0003] Electrochemical hydrogen and deuterium separation catalysts have been reported, but mainly in acidic environments. The problems faced by electrochemical hydrogen and deuterium separation in acidic environments are low current density and low separation ratio. Because metal sites in acidic electrolyte can directly adsorb hydrogen or deuterium, the selectivity of the electrode to hydrogen and deuterium is poor, and the separation ratio is difficult to further improve. The separation ratio of hydrogen and deuterium separation in alkaline environment can be further improved, but the catalysts with high separation ratio mostly follow the Heyrovsky mechanism and have poor performance. Due to the low activity of the Heyrovsky mechanism, when hydrogen evolution reaction occurs, H2 is more likely to be generated on the metal site, and D with higher free energy is left in the liquid phase, thereby achieving the purpose of isotopic separation and enrichment. Therefore, how to balance the high activity of the catalyst and the high selectivity of hydrogen and deuterium separation has become a key issue. If an electrolyte additive can be invented that does not affect the hydrogen evolution activity of the catalyst while universally improving the hydrogen and deuterium separation ratio of the cathode in electrolysis of water, it will play a promoting role in the production of heavy water as a byproduct of electrolysis of water / seawater to produce hydrogen coupled with hydrogen and deuterium separation.
[0004] To solve the above problems, the present application is proposed. SUMMARY
[0005] The present application provides an electrolyte additive that does not affect the hydrogen evolution activity of the catalyst while universally improving the hydrogen and deuterium separation ratio of the cathode in electrolysis of water, which plays a promoting role in the production of heavy water as a byproduct of electrolysis of water coupled with hydrogen and deuterium separation.
[0006] The first aspect of the present application provides an electrolyte additive for improving the separation ratio of electrolysis of water coupled with hydrogen and deuterium separation, wherein the electrolyte additive is selected from one or more of the following: an organic additive or an inorganic additive.
[0007] The organic additive is selected from one or more of the following: carboxyl-based organic matter, amine-based organic matter, and amide-based organic matter.
[0008] The inorganic additive is selected from one or more of the following: sodium salt, potassium salt, and lithium salt.
[0009] Preferably, the carboxyl-based organic matter is selected from one or more of formic acid, acetic acid, ethanedioic acid, butanedioic acid, propionic acid, citric acid, lactic acid, malic acid, malonic acid, oxalic acid, trifluoroacetic acid.
[0010] Preferably, the amine-based organic matter is selected from one or more of methylamine, ethylamine, ethanolamine, triethanolamine, polyethyleneimine, ethylenediamine, triethylenetetramine, hexamethylenetetramine, propylenediamine, butylenediamine, and ethylenediamine-terminated polyethyleneimine.
[0011] Preferably, the amide-based organic matter is selected from one or more of formamide, acetamide, N-N dimethylformamide, propionamide, malonamide, and polyacrylamide.
[0012] Preferably, the sodium salt is selected from one or more of sodium silicate, sodium sulfate, sodium sulfite, sodium carbonate, sodium phosphate, sodium phosphite, sodium borate, sodium fluoride, and sodium chloride.
[0013] The potassium salt is selected from one or more of potassium silicate, potassium sulfate, potassium sulfite, potassium carbonate, potassium phosphate, potassium phosphite, potassium borate, potassium fluoride, and potassium chloride.
[0014] The lithium salt is selected from one or more of lithium silicate, lithium sulfate, lithium sulfite, lithium carbonate, lithium phosphate, lithium phosphite, lithium borate, lithium fluoride, and lithium chloride.
[0015] The second aspect of the present application provides an electrolyte for electrolysis of water coupled with hydrogen-deuterium separation, wherein the electrolyte contains the electrolyte additive of any one of the first aspect of the present application.
[0016] Preferably, the electrolyte further contains alkali metal hydroxide and alkali metal halide salt, the concentration of the alkali metal hydroxide is 0.1-9 mol / L, the concentration of the alkali metal halide salt is 0-3 mol / L, the concentration of the electrolyte additive is 0.001-2 mol / L, and the deuterium content in the electrolyte is 100 ppm-70%.
[0017] The deuterium content refers to the ratio of the number of D atoms to the total number of H and D atoms, i.e., D / (H+D).
[0018] Preferably, the alkali metal hydroxide can be potassium hydroxide or sodium hydroxide, etc. The third aspect of the present application provides a method for improving the separation ratio of electrolysis of water coupled with hydrogen-deuterium separation, which comprises using an electrolyte containing the electrolyte additive of any one of the first aspect.
[0019] The fourth aspect of the present application provides the application of the electrolyte additive of the first aspect in the production of hydrogen coupled with electrochemical hydrogen-deuterium separation of water / sea water to produce heavy water as a byproduct.
[0020] Preferably, the electrolyte additive is used to further improve the H / D separation ratio.
[0021] Preferably, the cathode catalyst used in the electrolysis process can be iron or a catalyst containing iron elements. For example, iron oxide nanoparticle catalyst.
[0022] The preparation method of the iron oxide nanoparticle catalyst can be a prior art or a self-made method, and the self-made method comprises the following steps:
[0023] a. Iron salt, urea are added to water and dissolved by ultrasonic, and then transferred to an autoclave for hydrothermal reaction. The obtained solid is vacuum dried to obtain a ferric hydroxide powder material;
[0024] b. The ferric hydroxide powder material obtained in step a is calcined in a muffle furnace to obtain an iron oxide nanoparticle material.
[0025] Preferably, the cathode catalyst used in the electrolysis process is nickel, nickel foam or an electrode containing nickel elements. For example, nickel cobalt iron phosphide.
[0026] The preparation method of the nickel cobalt iron phosphide electrode can be a prior art or a self-made method, and the self-made method comprises the following steps:
[0027] a. Nickel salt, iron salt, cobalt salt and urea are added to water and dissolved by ultrasonic, and then transferred to an autoclave for hydrothermal reaction. The obtained electrode is a nickel cobalt iron hydroxide array electrode loaded on the nickel foam.
[0028] b. The nickel cobalt iron hydroxide array electrode loaded on the nickel foam is placed in a magnetic boat and placed downstream of a tube furnace. Sodium hypophosphite is placed in another magnetic boat and placed upstream of the tube furnace. The nickel cobalt iron phosphide array electrode loaded on the nickel foam is prepared by calcination.
[0029] In this application, the H / D separation ratio refers to the ratio of the atomic ratio of D to H in the gas phase to the atomic ratio of D to H in the liquid phase, and the calculation formula is:
[0030]
[0031] Preferably, the cathode used in the electrolysis process can also be a carbon rod electrode.
[0032] Compared with the prior art, the present application has the following beneficial effects:
[0033] 1. The present application first controls the electrolyte by adding carboxyl, amine, amide organic additives, uses the characteristics that organic ions will be adsorbed on the cathode surface in the electrolysis process, dynamically adjusts the hydrogen bond network on the cathode side, realizes the separation of hydrogen and deuterium. The hydrogen in the carboxyl, amine and amide functional groups around the cathode side will frequently exchange with the hydrogen and deuterium in the electrolyte, dynamically control the hydrogen bond network on the cathode surface, promote the dynamic adsorption and desorption of H / D on the cathode surface, disturb the inherent hydrogen bond network on the electrode surface, and further improve the separation ratio of electrolytic hydrogen and deuterium separation.
[0034] 2. In addition, the present application first controls the electrolyte by adding sodium salt, potassium salt, lithium salt and other inorganic additives, uses the characteristics that inorganic cations will be adsorbed on the cathode surface in the electrolysis process to disturb the hydrogen bond network, hinders the rapid transmission of deuterium on the hydrogen bond, improves the selectivity of the electrode to adsorb hydrogen, and realizes the separation of hydrogen and deuterium.
[0035] 3. The present application first realizes the further improvement of the separation ratio of hydrogen and deuterium separation while maintaining the hydrogen evolution activity of the electrode, and is universally applied to the improvement of the separation ratio of hydrogen and deuterium separation of all alkaline electrolytic water / sea water materials. The organic or inorganic additive can improve the separation ratio of hydrogen and deuterium from the original 5.4 to 11.3 at most.
[0036] 4. The present application uses organic additive engineering to control the separation ratio of hydrogen and deuterium separation coupled with seawater electrolysis, which not only realizes green electricity to produce green hydrogen, but also realizes the byproduct heavy water through the enrichment of deuterium in the liquid phase while the electrolyte is controlled without affecting the hydrogen evolution activity of the electrode. Heavy water can be used for the preparation of nuclear reactor raw materials and deuterium reagents, etc., which has high economic value and commercial value, thereby further reducing the cost of green hydrogen production, and has strong innovation and industrial feasibility. BRIEF DESCRIPTION OF DRAWINGS
[0037] Figure 1 The SEM image of the prepared iron oxide electrode.
[0038] Figure 2 The CV curve of the prepared iron oxide electrode.
[0039] Figure 3 The hydrogen and deuterium separation coefficient of the electrode after adding formic acid to the electrolyte.
[0040] Figure 4 The hydrogen and deuterium separation coefficient of the electrode after adding acetic acid to the electrolyte.
[0041] Figure 5 The hydrogen and deuterium separation coefficient of the electrode after adding oxalic acid to the electrolyte.
[0042] Figure 6 The hydrogen and deuterium separation coefficient of the electrode after adding succinic acid to the electrolyte.
[0043] Figure 7 The hydrogen-deuterium separation factor of the electrode after adding propionic acid to the electrolyte.
[0044] Figure 8 The hydrogen-deuterium separation factor of the electrode after adding citric acid to the electrolyte.
[0045] Figure 9 The hydrogen-deuterium separation factor of the electrode after adding lactic acid to the electrolyte.
[0046] Figure 10 The hydrogen-deuterium separation factor of the electrode after adding malic acid to the electrolyte.
[0047] Figure 11 The hydrogen-deuterium separation ratio comparison chart without and with the addition of carboxyl-based organic additives.
[0048] Figure 12 The constant current curve of the iron oxide electrode after adding propionic acid to the electrolyte.
[0049] Figure 13 The hydrogen-deuterium separation ratio of the electrode after adding amine-based organic matter to the electrolyte.
[0050] Figure 14 The hydrogen-deuterium separation ratio of the electrode after adding amide-based organic matter to the electrolyte.
[0051] Figure 15 The hydrogen-deuterium separation ratio of the electrode after adding different concentrations of amide-based organic matter to the electrolyte.
[0052] Figure 16 The hydrogen-deuterium separation ratio of the electrode after adding sodium salt to the electrolyte.
[0053] Figure 17 The hydrogen-deuterium separation ratio of the electrode after adding potassium salt to the electrolyte.
[0054] Figure 18 The hydrogen-deuterium separation ratio of the electrode after adding lithium salt to the electrolyte.
[0055] Figure 19 The hydrogen-deuterium separation ratio of the nickel-cobalt-iron phosphide electrode in high-concentration deuterium after adding amide organic additives.
[0056] Figure 20 The hydrogen-deuterium separation ratio of the nickel-cobalt-iron phosphide electrode in high-concentration deuterium. DETAILED DESCRIPTION
[0057] The present application will be described below with reference to specific examples, but the embodiments of the present application are not limited thereto. The experimental methods not specified in the examples are generally performed according to the conventional conditions and the conditions described in the manuals, or using the general equipment, materials, reagents, etc. as suggested by the manufacturers, unless otherwise specified. The raw materials required in the following examples and comparative examples are commercially available.
[0058] Separation ratio of iron oxide electrode electrolysis of seawater coupled with hydrogen-deuterium separation
[0059] Preparation and characterization of iron oxide catalyst
[0060] A 30-milliliter solution was prepared: 0.3 grams of iron nitrate, 0.6 grams of urea, dissolved in 30 milliliters of deionized water, and the solution was transferred to a 50-milliliter hydrothermal kettle, placed in an oven, the reaction temperature was 100 degrees Celsius, and the reaction time was 8 hours. The obtained powder material was washed with water and ethanol for 3 times, 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 material was transferred to a muffle furnace or a tube furnace, the reaction temperature was 300 degrees Celsius, the reaction time was 2 hours, and the obtained powder material was calcined in an air atmosphere, washed with water and ethanol for 3 times, and dried in a vacuum drying box at 60 degrees Celsius for 8 hours, and the obtained product was an iron oxide catalyst, specifically an iron oxide nanoparticle material.
[0061] The above iron oxide nanoparticle material was subjected to scanning electron microscope test (SEM), and the results are shown in Figure 1 , indicating that the iron oxide nanoparticles synthesized by the two-step method have obvious granular morphology, uniform size distribution, and a diameter of 10-50 nanometers.
[0062] Hydrogen evolution reaction performance test of iron oxide catalyst
[0063] The hydrogen evolution performance of the iron oxide nanoparticle catalyst for electrolysis of seawater coupled with hydrogen-deuterium separation was tested using a standard three-electrode system. The prepared iron oxide catalyst was 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 was selected as the reference electrode, and the 1*1 square centimeter iron oxide catalyst loaded on the carbon paper was used as the working electrode. The counter electrode was a nickel foam, and the electrolyte was a mixed simulated seawater solution of potassium hydroxide and sodium chloride, with a potassium hydroxide concentration of 1.0 mole per liter and a sodium chloride concentration of 0.5 mole per liter. First, cyclic voltammetry scanning was performed at a scan rate of 100 millivolts per second in the range of 0 to -1 V vs RHE until the electrode reached a stable state. Then, linear scanning was performed at a scan rate of 5 millivolts per second in the range of 0 to -1 V vs RHE, and the obtained linear scan voltammogram is shown in Figure 2 . As shown in Figure 2It can be seen that the overpotential of the iron oxide nanoparticle catalyst in alkaline seawater at a current density of 10 mA / cm2 is 185 mV, which proves its good hydrogen evolution performance
[0064] The iron oxide catalyst prepared above was loaded on a carbon paper substrate with a working area of 1*1 cm2 and a loading of 5 mg / cm2. The amount of adhesive Nafion used was 10 μL. The catalyst was used for tritium-deuterium separation ratio testing. The test electrolyte was a mixed solution of potassium hydroxide and sodium chloride, with a potassium hydroxide concentration of 1.0 mol / L and a sodium chloride concentration of 0.5 mol / L. The solution was composed of 50% ultrapure water and 50% heavy water (50% H2O + 50% D2O, H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2. The generated gas was collected and tested by gas chromatography to detect the content of D2, HD, and H2 gas in the gas phase, and the tritium-deuterium separation ratio was calculated.
[0065]
[0066] Example 1
[0067] Tritium-deuterium separation ratio test after adding carboxyl-based organic additives
[0068] The iron oxide catalyst prepared above was loaded on a carbon paper substrate with a working area of 1*1 cm2 and a loading of 5 mg / cm2. The amount of adhesive Nafion used was 10 μL. The catalyst was used for tritium-deuterium separation ratio testing. The test electrolyte was a mixed solution of potassium hydroxide and sodium chloride, with a potassium hydroxide concentration of 1.0 mol / L and a sodium chloride concentration of 0.5 mol / L. The solution was composed of 50% ultrapure water and 50% heavy water (50% H2O + 50% D2O, H / D atomic ratio = 1:1). The hydrogen evolution reaction was carried out at a constant current density of 400 mA / cm2. The generated gas was collected and tested by gas chromatography to detect the content of D2, HD, and H2 gas in the gas phase, and the tritium-deuterium separation ratio was calculated. Figure 3 To collect the ratio of D atoms to H atoms in the gas, the results showed that the H atom content in the generated gas was 87.2%, the D atom content was only 12.8%, and the tritium-deuterium separation ratio was 6.8, which was higher than the tritium-deuterium separation ratio of 6.1 of the iron oxide electrode in Comparative Example 1, confirming that the addition of carboxyl-based organic additives helps to improve the tritium-deuterium separation ratio.
[0069] Without changing other conditions, the formic acid added in the above step was replaced with an equal number of moles of acetic acid, and the tritium-deuterium separation ratio after adding acetic acid was tested. SeeFigure 4 .
[0070] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of oxalic acid, and the hydrogen-deuterium separation ratio after the addition of oxalic acid can be tested. See Figure 5 .
[0071] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of succinic acid, and the hydrogen-deuterium separation ratio after the addition of succinic acid can be tested. See Figure 6 .
[0072] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of propionic acid, and the hydrogen-deuterium separation ratio after the addition of propionic acid can be tested. See Figure 7 .
[0073] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of citric acid, and the hydrogen-deuterium separation ratio after the addition of citric acid can be tested. See Figure 8 .
[0074] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of lactic acid, and the hydrogen-deuterium separation ratio after the addition of lactic acid can be tested. See Figure 9 .
[0075] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of malic acid, and the hydrogen-deuterium separation ratio after the addition of malic acid can be tested. See Figure 10 .
[0076] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of malonic acid, and the hydrogen-deuterium separation ratio after the addition of malonic acid can be tested. See Figure 11 .
[0077] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of oxalic acid, and the hydrogen-deuterium separation ratio after the addition of oxalic acid can be tested. See Figure 11 .
[0078] Other conditions being unchanged, the formic acid added in the above step is replaced by an equal number of moles of trifluoroacetic acid, and the hydrogen-deuterium separation ratio after the addition of trifluoroacetic acid can be tested. See Figure 11 .
[0079] The results of Comparative Example 1 (blank item in Table 1) and Example 1 are shown in Table 1. It can be seen that after adding the carboxyl organic additive, the hydrogen-deuterium separation ratio is greatly improved, and is increased to 6.8 or even 11.3, which shows that the carboxyl organic additive can be adsorbed on the surface of the cathode during electrolysis, and the H in the carboxyl functional group can be exchanged with hydrogen-deuterium in the electrolyte frequently, so as to dynamically control the hydrogen bond network on the surface of the cathode, promote the frequent adsorption and desorption of hydrogen-deuterium on the surface of the cathode, disturb the hydrogen bond network, and further improve the hydrogen-deuterium separation ratio of the alkaline electrolytic seawater coupling.
[0080] Stability of electrolytic seawater coupling hydrogen-deuterium separation after adding propionic acid organic additive in Example 2
[0081] The stability of the electrode for electrolytic seawater coupling hydrogen-deuterium separation after adding the propionic acid organic additive is evaluated by using a standard two-electrode system. The cathode is an iron oxide electrode with an effective area of 1*1 square centimeter, and the anode is a nickel-cobalt-phosphorus iron electrode. The electrolyte is a mixed solution of potassium hydroxide and sodium chloride, wherein the concentration of potassium hydroxide is 1.0 mole per liter, and the concentration of sodium chloride is 0.5 mole per liter. The solution is prepared by using H2O (the deuterium content is 146 ppm, which is the natural abundance of deuterium in nature). Propionic acid is added to the electrolyte, and the concentration of propionic acid is 0.01 mole per liter. The stability test is carried out at a constant current of 400 milliampere per square centimeter, and the constant current curve obtained is shown in Figure 12 .
[0082] As can be seen from Figure 12 , after adding the propionic acid organic additive, the hydrogen evolution stability of the catalyst in the alkaline seawater is not affected, and the long-time hydrogen evolution coupling hydrogen-deuterium separation stability can be maintained for about 500 hours. The water sample after long-time separation is detected by using a mass spectrometer, and the results show that the deuterium abundance in the electrolyte is increased from 146 ppm to 332 ppm, which is nearly doubled, proving the hydrogen-deuterium screening and the enrichment of deuterium in the electrolyte.
[0083] In addition, since the higher the deuterium concentration of the solution water is, the more difficult it is to achieve hydrogen-deuterium separation, due to the increasing deuterium content in the solution, the difficulty of selectively producing hydrogen gas instead of deuterium gas by the electrode is increased. Therefore, in the scheme of the present application, the deuterium content in the initial electrolyte water is 146 ppm or less, for example, 100 ppm, 50 ppm, 1 ppm, 0.1 ppm, 0.01 ppm, etc., which can achieve hydrogen-deuterium separation, and deuterium is continuously enriched in the liquid phase.
[0084] Hydrogen-deuterium separation ratio of phosphatized nickel-cobalt-iron electrode in Comparative Example 2
[0085] Preparation of phosphatized nickel-cobalt-iron electrode:
[0086] Configuration 30ml solution: nickel nitrate 0.1g, iron nitrate 0.15g, cobalt nitrate 0.1g, urea 0.8g, ammonium fluoride 0.5g, dissolved in 30ml deionized water, the solution was transferred to a 50ml hydrothermal kettle, the cleaned 3*4 square centimeter nickel foam was put into the inner liner of the hydrothermal kettle, and then transferred to an oven, the reaction temperature was 100 degrees Celsius, and the reaction time was 12 hours. The obtained product was washed with water and 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 nickel-cobalt-iron hydroxide material. The prepared nickel-cobalt-iron hydroxide material was transferred to the downstream of a tube furnace, 0.5g of sodium hypophosphite was placed in the upstream, the reaction temperature was 300 degrees Celsius, the reaction time was 2 hours, and the obtained material was calcined under a nitrogen atmosphere, then washed with water and 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 nickel-cobalt-iron phosphide electrode.
[0087] The cathode adopts a nickel-cobalt-iron phosphide electrode, and the anode adopts a nickel foam electrode, which is used for hydrogen-deuterium separation ratio test. The test electrolyte is 1 mol / L sodium hydroxide solution, 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 mA / cm2, the generated 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 hydrogen-deuterium separation ratio is calculated.
[0088] Example 3 Hydrogen-deuterium separation ratio test after adding amine-based organic additive
[0089] The nickel-cobalt-iron phosphide electrode is used for hydrogen-deuterium separation ratio test. The cathode adopts a nickel-cobalt-iron phosphide electrode, and the anode adopts a nickel foam electrode. The test electrolyte is 1 mol / L sodium hydroxide solution, and the solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). Methylamine is added to the electrolyte to make the concentration of methylamine 0.01 mol / L. The hydrogen evolution reaction is carried out at a constant current density of 400 mA / cm2, 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 hydrogen-deuterium separation ratio is calculated. Figure 13 The hydrogen-deuterium separation ratio of the electrode after adding methylamine is collected. The results show that the H atom accounts for 87.1% in the generated gas, the D atom accounts for only 12.9%, and the hydrogen-deuterium separation ratio is 6.8, which is higher than the hydrogen-deuterium separation ratio of 5.4 of the nickel-cobalt-iron phosphide electrode in Comparative Example 2, which confirms that the addition of amine-based organic additive helps to improve the hydrogen-deuterium separation ratio.
[0090] Without changing other conditions, the methylamine added in the above step is replaced by an equimolar amount of ethylamine, and the hydrogen-deuterium separation ratio after adding ethylamine can be tested.Figure 13 )
[0091] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of ethanolamine, and the hydrogen-deuterium separation ratio after the addition of ethanolamine can be tested. Figure 13 )
[0092] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of triethanolamine, and the hydrogen-deuterium separation ratio after the addition of triethanolamine can be tested. Figure 13 )
[0093] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of polyethyleneimine, and the hydrogen-deuterium separation ratio after the addition of polyethyleneimine can be tested. Figure 13 )
[0094] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of ethylenediamine, and the hydrogen-deuterium separation ratio after the addition of ethylenediamine can be tested. Figure 13 )
[0095] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of ethylenediamine-terminated polyethyleneimine, and the hydrogen-deuterium separation ratio after the addition of ethylenediamine-terminated polyethyleneimine can be tested. Figure 13 )
[0096] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of triethylenetetramine, and the hydrogen-deuterium separation ratio after the addition of triethylenetetramine can be tested. Figure 13 )
[0097] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of hexamethylenetetramine, and the hydrogen-deuterium separation ratio after the addition of hexamethylenetetramine can be tested. Figure 13 )
[0098] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of propylenediamine, and the hydrogen-deuterium separation ratio after the addition of propylenediamine can be tested. Figure 13 )
[0099] Other conditions being unchanged, the methanamine added in the above step is replaced by an equal number of moles of butylenediamine, and the hydrogen-deuterium separation ratio after the addition of butylenediamine can be tested. Figure 13 )
[0100] Comparative Example 2 and Example 3 can be compared: after adding amine-based organic additives, the hydrogen-deuterium separation ratio is greatly improved, which is increased to 6.8 to 8.6, indicating that the amine-based organic additive can be adsorbed on the surface of the cathode during electrolysis, and the H in the NH functional group can exchange with the hydrogen and deuterium in the electrolyte frequently, dynamically regulate the hydrogen bond network on the surface of the cathode, promote the frequent adsorption and desorption of hydrogen and deuterium on the surface of the cathode, disturb the hydrogen bond network, and further improve the hydrogen-deuterium separation ratio of the alkaline electrolytic seawater coupling.
[0101] The hydrogen-deuterium separation ratio of the carbon rod electrode electrolytic seawater coupling
[0102] The carbon rod electrode is used as the cathode, and the foam nickel electrode is used as the anode for hydrogen-deuterium separation ratio test. The test electrolyte is a mixed solution of potassium hydroxide and sodium chloride, the concentration of potassium hydroxide is 6.0 mol / L, and the concentration of sodium chloride is 3.0 mol / L. 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 mA / cm2, the generated 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 hydrogen-deuterium separation ratio is calculated.
[0103] Example 4 hydrogen-deuterium separation ratio test after adding amide organic additive
[0104] The carbon rod is used as the cathode, and the foam nickel electrode is used as the anode for hydrogen-deuterium separation ratio test. The test electrolyte is a mixed solution of potassium hydroxide and sodium chloride, the concentration of potassium hydroxide is 6 mol / L, and the concentration of sodium chloride is 3 mol / L. The solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). Formamide is added to the electrolyte to make the concentration of formamide 0.01 mol / L. The hydrogen evolution reaction is carried out at a constant current density of 400 mA / cm2, 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 hydrogen-deuterium separation ratio is calculated. Figure 14 The collected D2+HD and H2 gas content shows that the H atom accounts for 87.9% of the generated gas, and the D atom accounts for only 12.1%, and the hydrogen-deuterium separation ratio is 7.2, which is higher than the hydrogen-deuterium separation ratio of 6.5 of the carbon rod electrode in Comparative Example 3, confirming that the addition of amide organic additive can improve the hydrogen-deuterium separation capacity.
[0105] Without changing other conditions, the formamide added in the above step is replaced with an equimolar amount of acetamide, and the hydrogen-deuterium separation ratio after adding acetamide can be tested. Figure 14 )
[0106] Other conditions being unchanged, the formamide added in the above step is replaced by an equal number of moles of N-N dimethyl formamide, and the hydrogen-deuterium separation ratio after adding N-N dimethyl formamide can be tested. Figure 14 )
[0107] Other conditions being unchanged, the formamide added in the above step is replaced by an equal number of moles of propionamide, and the hydrogen-deuterium separation ratio after adding propionamide can be tested. Figure 14 )
[0108] Other conditions being unchanged, the formamide added in the above step is replaced by an equal number of moles of malonamide, and the hydrogen-deuterium separation ratio after adding malonamide can be tested. Figure 14 )
[0109] Other conditions being unchanged, the formamide added in the above step is replaced by an equal number of moles of polyacrylamide, and the hydrogen-deuterium separation ratio after adding polyacrylamide can be tested. Figure 14 )
[0110] In order to test the influence of different concentrations of additives on the hydrogen-deuterium separation ratio, the concentration of the amide organic additive added in the above step is changed to 0.001 moles per liter, 0.05 moles per liter and 2 moles per liter, other conditions being unchanged, the hydrogen-deuterium separation ratio of the electrode after adding amide organic additives of different concentrations is tested, and the results are shown in Table 1. Figure 15 As can be seen from Table 1, the hydrogen-deuterium separation ratio can be increased from 6.5 to 7.0 by adding 0.001 moles per liter of formamide, and the hydrogen-deuterium separation ratio continues to increase with the increase of the concentration of amide organic additives, and the hydrogen-deuterium separation ratio is increased to 8.6 when 0.05 moles per liter of formamide is added, and the hydrogen-deuterium separation ratio is increased to 9.5 when 2 moles of formamide is added.
[0111] Figure 14 In order to test the influence of different concentrations of additives on the hydrogen-deuterium separation ratio, the concentration of the amide organic additive added in the above step is changed to 0.001 moles per liter, 0.05 moles per liter and 2 moles per liter, other conditions being unchanged, the hydrogen-deuterium separation ratio of the electrode after adding amide organic additives of different concentrations is tested, and the results are shown in Table 1.
[0112] Example 7 Test of hydrogen-deuterium separation ratio after adding sodium salt
[0113] The cathode is the phosphatized nickel-cobalt-iron electrode of Comparative Example 2, the anode is a nickel foam electrode, and the electrolyte is 1 mole per liter of sodium hydroxide, which is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). Sodium silicate is added to the electrolyte to make the concentration of sodium silicate 0.05 moles per liter. The hydrogen evolution reaction is carried out at a constant current density of 400 milliampere per square centimeter, the generated hydrogen gas is collected, and gas chromatography is performed to detect the content of D2, HD and H2 in the gas phase, and the hydrogen-deuterium separation ratio is calculated. The content of D2+HD and H2 is collected, and the results show that the proportion of H atoms in the generated gas is 89.1%, the proportion of D atoms is only 10.9%, and the hydrogen-deuterium separation ratio is 8.2( Figure 16 ), which is higher than the hydrogen-deuterium separation ratio of 5.4( Figure 16 ) of the phosphatized nickel-cobalt-iron electrode of Comparative Example 2 (blank item), which confirms that the addition of sodium salt helps to improve the hydrogen-deuterium separation ratio.
[0114] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium sulfate, and the hydrogen-deuterium separation ratio after the addition of sodium sulfate can be tested. Figure 16
[0115] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium sulfite, and the hydrogen-deuterium separation ratio after the addition of sodium sulfite can be tested. Figure 16
[0116] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium carbonate, and the hydrogen-deuterium separation ratio after the addition of sodium carbonate can be tested. Figure 16
[0117] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium phosphate, and the hydrogen-deuterium separation ratio after the addition of sodium phosphate can be tested. Figure 16
[0118] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium phosphite, and the hydrogen-deuterium separation ratio after the addition of sodium phosphite can be tested. Figure 16
[0119] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium borate, and the hydrogen-deuterium separation ratio after the addition of sodium borate can be tested. Figure 16
[0120] Without changing other conditions, the sodium silicate added in the above step is replaced with an equal number of moles of sodium fluoride, and the hydrogen-deuterium separation ratio after the addition of sodium fluoride can be tested. Figure 16
[0121] Other conditions being the same, the sodium silicate added in the above step is replaced by an equal number of moles of sodium chloride, and the hydrogen-deuterium separation ratio after the addition of sodium chloride can be tested. Figure 16 )
[0122] Figure 16 It can be seen that, compared with Comparative Example 2, the addition of sodium salt helps to improve the hydrogen-deuterium separation ratio.
[0123] Example 8 Test of hydrogen-deuterium separation ratio after the addition of potassium salt
[0124] The cathode is the phosphatized nickel-cobalt-iron electrode of Comparative Example 2, the anode is a foamed nickel electrode, the test electrolyte is a 1 mol / L sodium hydroxide solution, and the solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). Potassium carbonate is added to the electrolyte to make the concentration of potassium carbonate 2 mol / L, and the hydrogen evolution reaction is carried out at a constant current density of 400 mA / cm2. The generated hydrogen gas is collected and tested by gas chromatography to detect the content of D2, HD and H2 in the gas phase, and the hydrogen-deuterium separation ratio is calculated. The content of D2+HD and H2 generated by the electrode after the addition of potassium salt is collected, and the results show that the H atom accounts for 88.5% of the generated gas, the D atom accounts for only 11.5%, and the hydrogen-deuterium separation ratio is 7.7( Figure 17 ), which is higher than the hydrogen-deuterium separation ratio of 5.4( Figure 17 ) of the phosphatized nickel-cobalt-iron electrode of Comparative Example 2 (blank), which proves that the addition of potassium salt helps to improve the hydrogen-deuterium separation ratio.
[0125] Other conditions being the same, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium sulfate, and the hydrogen-deuterium separation ratio after the addition of potassium sulfate can be tested. Figure 17 )
[0126] Other conditions being the same, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium sulfite, and the hydrogen-deuterium separation ratio after the addition of potassium sulfite can be tested. Figure 17 )
[0127] Other conditions being the same, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium silicate, and the hydrogen-deuterium separation ratio after the addition of potassium carbonate can be tested. Figure 17 )
[0128] Other conditions being the same, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium phosphate, and the hydrogen-deuterium separation ratio after the addition of potassium phosphate can be tested. Figure 17 )
[0129] Other conditions being the same, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium phosphite, and the hydrogen-deuterium separation ratio after the addition of potassium phosphite can be tested. Figure 17 )
[0130] Other conditions being unchanged, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium borate, and the hydrogen-deuterium separation ratio after the addition of potassium borate is tested. Figure 17 )
[0131] Other conditions being unchanged, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium fluoride, and the hydrogen-deuterium separation ratio after the addition of potassium fluoride is tested. Figure 17 )
[0132] Other conditions being unchanged, the potassium carbonate added in the above step is replaced by an equal number of moles of potassium chloride, and the hydrogen-deuterium separation ratio after the addition of potassium chloride is tested. Figure 17 )
[0133] Figure 18 It can be seen that, compared with Comparative Example 2, it is confirmed that the addition of potassium salt helps to improve the hydrogen-deuterium separation ratio.
[0134] Example 9 Test of Hydrogen-Deuterium Separation Ratio after the Addition of Lithium Salt
[0135] The cathode uses the nickel-cobalt-iron phosphide electrode of Comparative Example 2, the anode uses a nickel foam electrode, and the test electrolyte is 0.1 mol / L sodium hydroxide, and the solution is composed of 50% ultrapure water and 50% heavy water (H / D atomic ratio = 1:1). Lithium sulfate is added to the electrolyte to make its concentration 0.005 mol / L, and the hydrogen evolution reaction is carried out at a constant current density of 400 mA / cm2. The generated hydrogen gas is collected and tested by gas chromatography to detect the content of D2, HD and H2 gas in the gas phase, and the hydrogen-deuterium separation ratio is calculated. The content of D2+HD and H2 gas generated by the nickel-cobalt-iron phosphide electrode after the addition of lithium salt is collected, and the results show that the H atom accounts for 87.0% and the D atom accounts for only 13.0% in the generated gas, and the hydrogen-deuterium separation ratio is 6.7 Figure 18 , which is higher than the hydrogen-deuterium separation ratio 5.4 Figure 18 of the nickel-cobalt-iron phosphide electrode of Comparative Example 2 (blank), confirming that the addition of lithium salt helps to improve the hydrogen-deuterium separation ratio.
[0136] Other conditions being unchanged, the lithium sulfate added in the above step is replaced by an equal number of moles of lithium silicate, and the hydrogen-deuterium separation ratio after the addition of lithium silicate is tested. Figure 18 )
[0137] Other conditions being unchanged, the lithium sulfate added in the above step is replaced by an equal number of moles of lithium sulfite, and the hydrogen-deuterium separation ratio after the addition of lithium sulfite is tested. Figure 18 )
[0138] Other conditions being unchanged, the lithium sulfate added in the above step is replaced by an equal number of moles of lithium carbonate, and the hydrogen-deuterium separation ratio after the addition of lithium carbonate is tested. Figure 18 )
[0139] Other conditions remain unchanged, the above-mentioned step of adding lithium sulfate to replace the same number of lithium phosphate, namely the test can be obtained after the addition of lithium phosphate hydrogen deuterium separation ratio. Figure 18 )
[0140] Other conditions remain unchanged, the above-mentioned step of adding lithium sulfate to replace the same number of lithium phosphate, namely the test can be obtained after the addition of lithium phosphate hydrogen deuterium separation ratio. Figure 18 )
[0141] Other conditions remain unchanged, the above-mentioned step of adding lithium sulfate to replace the same number of lithium phosphate, namely the test can be obtained after the addition of lithium phosphate hydrogen deuterium separation ratio. Figure 18 )
[0142] Other conditions remain unchanged, the above-mentioned step of adding lithium sulfate to replace the same number of lithium phosphate, namely the test can be obtained after the addition of lithium phosphate hydrogen deuterium separation ratio. Figure 18 )
[0143] Other conditions remain unchanged, the above-mentioned step of adding lithium sulfate to replace the same number of lithium phosphate, namely the test can be obtained after the addition of lithium phosphate hydrogen deuterium separation ratio. Figure 19 )
[0144] Figure 20 It can be seen that, compared with Comparative Example 2, it is confirmed that the addition of lithium salt helps to improve the hydrogen deuterium separation ratio.
[0145] Example 10 High-concentration deuterium electrolytic seawater coupled hydrogen deuterium separation
[0146] The standard two-electrode system is used to evaluate the hydrogen deuterium separation ratio of the electrode after adding amide in high-concentration deuterium. The cathode is a nickel phosphorus cobalt iron electrode with an effective area of 1*1 square centimeter, and the anode is a nickel foam electrode. The electrolyte is a mixed solution of potassium hydroxide and sodium chloride, wherein the concentration of potassium hydroxide is 9.0 moles per liter, and the concentration of sodium chloride is 3.0 moles per liter. Additional malonamide is added to the electrolyte to make the concentration of malonamide 0.01 moles per liter. The solution is composed of 30% ultrapure water and 70% heavy water (H / D atomic ratio = 3:7). The hydrogen evolution reaction is carried out at a constant current of 400 milliampere per square centimeter, and the gas produced by the cathode is collected for gas chromatography test to detect the content of D2, HD and H2 gas in the gas phase. The results show that the H atom accounts for 76.2% of the generated gas, and the D atom accounts for only 23.8%, and the hydrogen deuterium separation ratio is 7.5 Example number ).
[0147] In the comparative experiment, the electrolyte does not add malonamide, and other conditions remain unchanged. The results show that: the H atom accounts for 67.5% of the generated gas, and the D atom accounts for 32.5%, and the hydrogen deuterium separation ratio is 4.85 Carboxyl type of additive), which is lower than the separation ratio of 7.5 after adding malonamide, indicating that the organic additive in high concentration of deuterium still has obvious promoting effect on the separation of hydrogen and deuterium.
[0148] Table 1 Hydrogen-deuterium separation ratio of different carboxyl additives
[0149] Separation ratio Formic acid Acetic acid 1 Oxalic acid 6.8 2 Succinic acid 10.2 3 Propionic acid 8.9 4 Citric acid 7.5 5 Lactic acid 11.3 6 Malic acid 10.6 7 Malonic acid 9.5 8 Oxalic acid 8.7 9 Trifluoroacetic acid 8.5 10 Blank 7.6 11 9.2 12 6.1
Claims
1. An electrolyte additive for improving the separation ratio of electrolytic water coupled protium-deuterium separation, characterized by, The electrolyte additive is selected from one or more of organic additives or inorganic additives; The organic additive is selected from one or more of carboxyl-based organic matter, amine-based organic matter, and amide-based organic matter; The inorganic additive is selected from one or more of sodium salt, potassium salt, and lithium salt.
2. The electrolyte additive for improving the separation ratio of the electrolytic water coupled H-D separation according to claim 1, characterized by, The carboxyl-based organic matter is selected from one or more of formic acid, acetic acid, oxalic acid, succinic acid, propionic acid, citric acid, lactic acid, malic acid, malonic acid, oxalic acid, and trifluoroacetic acid.
3. The electrolyte additive for improving the separation ratio of the electrolytic water coupled H-D separation according to claim 1, characterized by, The amine-based organic matter is selected from one or more of methylamine, ethylamine, ethanolamine, triethanolamine, polyethyleneimine, ethylenediamine, triethylenetetramine, hexamethylenetetramine, propylenediamine, butylenediamine, and ethylenediamine-terminated polyethyleneimine.
4. The electrolyte additive for improving the separation ratio of the electrolytic water coupled H-D separation according to claim 1, characterized by, The amide-based organic matter is selected from one or more of formamide, acetamide, N-N dimethylformamide, propionamide, malonamide, and polyacrylamide.
5. The electrolyte additive for enhancing the separation ratio of the electrolytic water coupled H-D separation of claim 1, wherein The sodium salt is selected from one or more of sodium silicate, sodium sulfate, sodium sulfite, sodium carbonate, sodium phosphate, sodium phosphite, sodium borate, sodium fluoride, and sodium chloride; The potassium salt is selected from one or more of potassium silicate, potassium sulfate, potassium sulfite, potassium carbonate, potassium phosphate, potassium phosphite, potassium borate, potassium fluoride, and potassium chloride; The lithium salt is selected from one or more of lithium silicate, lithium sulfate, lithium sulfite, lithium carbonate, lithium phosphate, lithium phosphite, lithium borate, lithium fluoride, and lithium chloride.
6. An electrolyte for electrolysis of water coupled to hydrogen deuterium separation, characterized in that, The electrolyte contains the electrolyte additive of any one of claims 1-5.
7. The electrolyte for electrolysis of water coupled with protium-deuterium separation according to claim 6, wherein The electrolyte further contains alkali metal hydroxide and alkali metal halide, the concentration of the alkali metal is 0.1-9 mol / L, the concentration of the alkali metal halide is 0-3 mol / L, the concentration of the electrolyte additive is 0.001-2 mol / L, and the concentration of deuterium in the electrolyte is 100 ppm-70%.
8. A method of improving the separation ratio of a separation of protium-deuterium coupled to electrolysis of water, the method comprising: The electrolyte containing the electrolyte additive of any one of claims 1-5 is used.
9. Use of the electrolyte additive of any one of claims 1-5 in the production of hydrogen from electrolysis of water / sea water coupled with electrochemical separation of protium and deuterium to produce heavy water as a byproduct.