Hydrogen production system, hydrogen production method and power system using the same

Abstract

The present invention relates to a hydrogen production system, comprising a gaseous ammonia / liquid ammonia feeding part, a first conductive part, a second conductive part, an electrolysis part and a product gas discharging part, wherein the electrolysis part comprises an electrolyte composition, for a gaseous ammonia system, the electrolyte composition comprises an ammonium salt and a solvent capable of dissolving the ammonium salt, and for a liquid ammonia system, the electrolyte is an ammonium salt, wherein the ammonium salt is selected from ammonium benzenesulfonate, ammonium sulfate, ammonium bicarbonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate or any combination thereof.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogen energy preparation, and more specifically, relates to a device and method for preparing hydrogen using electrochemical technology. Background Art

[0002] Hydrogen energy is gaining more and more attention as a clean energy source. However, using hydrogen directly as fuel has the problems of high cost, low storage efficiency and poor safety performance. Safe, efficient and economical hydrogen supply and storage technology is one of the key technologies to realize the utilization of hydrogen energy. However, the development of efficient and economical hydrogen storage materials and systems still faces huge technical challenges.

[0003] Ammonia is a hydrogen-rich substance with a mass fraction of 17.6%. Its hydrogen content is higher than that of hydrogen-containing substances such as water and alcohol, and it is a good hydrogen storage carrier. Ammonia is low-cost, easy to transport and store, and the relevant technology and infrastructure are mature, so it can be used as a high-energy liquid fuel. However, since ammonia easily poisons proton exchange membrane fuel cells, it is difficult to directly use it as a fuel in fuel cell systems. Developing efficient ammonia decomposition technology to decompose ammonia into hydrogen so that it can be used directly or supplied to hydrogen fuel cells as needed is a technical problem that needs to be solved for ammonia as a hydrogen storage carrier.

[0004] At present, the method of preparing hydrogen from ammonia is usually based on high-temperature thermochemical decomposition technology. According to the chemical reaction kinetics, under high temperature conditions, the decomposition efficiency of ammonia can reach 99%. Although non-patent literature 1 reports that nickel-based catalysts have high catalytic activity for ammonia decomposition, the ammonia decomposition reaction still needs to be carried out under high temperature conditions above 400°C. This high-temperature thermochemical decomposition technology can be used for large-scale industrial ammonia decomposition to produce hydrogen, but when ammonia is used for small-scale hydrogen production and hydrogen supply to mobile power sources, such as on-board fuel cells, it is necessary to develop safe and efficient low-temperature ammonia decomposition hydrogen production technology below 100°C.

[0005] Non-patent document 2 reports that active perovskites (SrTiO3 or BaTiO3) can decompose ammonia into hydrogen and nitrogen at room temperature, but the conversion rate is very low, and 900°C is required to extract the decomposed nitrogen and hydrogen from the perovskite material. Using electrical energy to provide energy to decompose ammonia molecules into hydrogen molecules and nitrogen molecules makes it possible to produce hydrogen by low-temperature ammonia decomposition below 100°C.

[0006] Non-patent document 3 and non-patent document 4 report methods for preparing hydrogen by electrolyzing strongly alkaline ammonia-containing wastewater. Ammonia undergoes an electrode reaction at the anode as shown in formula (1) and is oxidized to nitrogen. Water undergoes an electrode reaction at the cathode as shown in formula (2) and is reduced to hydrogen. Non-patent document 5 and non-patent document 6 also conducted electrode optimization research based on the above system. However, the above-mentioned ammonia electrolysis system has two problems: 1) Ammonia is easily peroxidized in the system to generate corrosive nitrates; 2) The actual source of hydrogen in the reaction system is the hydrogen atoms in the water, and the true ammonia decomposition to produce hydrogen is not achieved.

[0007] 2NH3(aq)+6OH - →N2(g)+6H2O+6e - (1)

[0008] 6H2O+6e - →3H2(g)+6OH - (2)

[0009] Non-patent literature 7 and non-patent literature 8 report the use of metal amides (KNH2, etc.) as supporting electrolyte electrolyte ammonia, and the electrode reactions shown in formulas (3) and (4) occur at the anode and cathode, respectively, to decompose ammonia into hydrogen and nitrogen. By increasing the concentration of KNH2, the resistance of the system can be significantly reduced, and the current efficiency is 85%. By optimizing the electrodes, the current efficiency can be further increased to 96.9%. However, metal amides are very likely to react with water or oxygen in the air to catch fire, posing a great safety hazard.

[0010] 3NH2 - →1 / 2N2+2NH3+3e - (3)

[0011] 3NH3+3e - →3 / 2H2+3NH2 - (4)

[0012] Non-patent document 9 and patent document 1 report the use of ammonium salts (NH4PF6, NH4Cl, NH4Br, NH4I, NH4NO3, etc.) as supporting electrolytes, with electrode reactions as shown in equations (5) and (6) occurring at the anode and cathode, respectively, to electrolyze liquid ammonia into hydrogen and nitrogen.

[0013] 4NH3→1 / 2N2+3H + +3e - (5)

[0014] 3NH4 + +3e - →3 / 2H2+3NH3 (6)

[0015] The above system partially solves the safety problem of metal amide compounds. However, this reaction system has high requirements for electrolysis system equipment, which must meet the requirements of pressure resistance and low temperature resistance, resulting in complex electrolysis equipment manufacturing and high cost. In addition, the ammonium salt electrolyte used is highly corrosive, and the electrolysis equipment must also meet the requirements of corrosion resistance. At the same time, the electrolysis ammonia systems that have been publicly reported lack a design for effectively separating the hydrogen and nitrogen generated after electrolysis from the unelectrolyzed ammonia, and cannot provide high-purity hydrogen that can be applied to equipment such as hydrogen fuel cells.

[0016] Non-patent document 1: Top. Catal. 59 (2016) 1438–1457.

[0017] Non-patent document 2: Chem. Commun., 46 (2010) 3982-3984.

[0018] Non-patent document 3: J. Power Sources, 142 (2005) 18-26.

[0019] Non-patent document 4: J. Power Sources, 192 (2009) 573-581.

[0020] Non-patent document 5: J. Electrochem. Soc., 159 (2012) F91–F96.

[0021] Non-patent document 6: J. Power Sources, 223 (2013) 221-231.

[0022] Non-patent document 7: Chem. Commun., 46 (2010) 7775-7.

[0023] Non-patent document 8: J. Alloy. Compd. 509 (2011) S891-S894.

[0024] Non-patent document 9: Energ. Environ. Sci., 8 (2015) 2775-2781.

[0025] Patent document 1: CN106319555A

[0026] Therefore, there is an urgent need in the art for a system and method that can safely and efficiently directly decompose ammonia to produce hydrogen, so as to solve one or more technical problems existing in the art. Summary of the invention

[0027] In a first aspect, a hydrogen production system is provided, comprising a gaseous ammonia / liquid ammonia feed section, a first conductive section, a second conductive section, an electrolysis section, and a product gas discharge section, wherein the electrolysis section comprises an electrolyte composition. For a gaseous ammonia system, the electrolyte composition comprises an ammonium salt and a solvent capable of dissolving the ammonium salt, and for a liquid ammonia system, the electrolyte is an ammonium salt.

[0028] In one embodiment, the electrolyte composition does not contain water. In another embodiment, the electrolyte composition further comprises an ionic liquid that is miscible with the solvent. In yet another embodiment, the ionic liquid is a protic ionic liquid. In a further embodiment, the electrolyte composition further comprises a substance that can provide hydrogen protons.

[0029] In one embodiment, the ammonium salt is an organic ammonium salt, an inorganic ammonium salt or any combination thereof containing ammonium ions. In a specific embodiment, the ammonium salt includes ammonium benzenesulfonate, ammonium sulfate, ammonium bicarbonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate, etc. or any combination thereof. In another embodiment, the solvent is a hydrocarbon, a carbon hydrogen nitrogen compound, a carbon hydrogen oxygen nitrogen compound or any combination thereof. In a specific embodiment, the solvent includes dimethylformamide, acetonitrile, N-methylpyrrolidone, cyclohexane, etc. or any combination thereof. In another embodiment, the substance capable of providing hydrogen protons includes liquid acid, solid acid or any combination thereof. In a specific embodiment, the substance capable of providing hydrogen protons includes H-type molecular sieve, ion exchange resin, carbonic acid, benzenesulfonic acid, sulfuric acid or any combination thereof.

[0030] In one embodiment, the ionic liquid comprises cations and anions, the cations comprising quaternary ammonium salt ions, imidazolium salt ions, pyrrole salt ions, etc. or any combination thereof, and the anions comprising tetrafluoroborate ions, hexafluorophosphate ions or any combination thereof. In another embodiment, the protic ionic liquid comprises cations and anions, the cations comprising 1-alkyl imidazolium cations, primary ammonium cations, secondary ammonium cations, tertiary ammonium cations or any combination thereof, and the anions comprising carboxylates, trifluoroacetates, bis(perfluoroethylsulfonyl)imides, bis(trifluoromethanesulfonyl)imides, nitrates or any combination thereof.

[0031] In one embodiment, the first conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the first conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the first conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0032] In one embodiment, the second conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the second conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the second conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0033] In one embodiment, the first conductive portion is an anode for an electrolysis reaction, and the second conductive portion is a cathode for an electrolysis reaction. In another embodiment, the hydrogen production system further comprises a reference electrode. In yet another embodiment, the hydrogen production system further comprises a gas separation system. In a further embodiment, the gas separation system comprises a nitrogen permeable membrane and a hydrogen permeable membrane disposed in a product gas discharge portion.

[0034] In a second aspect, a method for producing hydrogen is provided, comprising generating hydrogen using the hydrogen production system described herein; and collecting and storing the generated hydrogen. In one embodiment, the hydrogen production system comprises a gaseous ammonia / liquid ammonia feed section, a first conductive section, a second conductive section, an electrolysis section, and a product gas discharge section, wherein the electrolysis section comprises an electrolyte composition. For a gaseous ammonia system, the electrolyte composition contains an ammonium salt and a solvent that can dissolve the ammonium salt, and for a liquid ammonia system, the electrolyte is an ammonium salt.

[0035] In one embodiment, the electrolyte composition does not contain water. In another embodiment, the electrolyte composition further comprises an ionic liquid that is miscible with the solvent. In yet another embodiment, the ionic liquid is a protic ionic liquid. In a further embodiment, the electrolyte composition further comprises a substance that can provide hydrogen protons.

[0036] In one embodiment, the ammonium salt is an organic ammonium salt containing ammonium ions, an inorganic ammonium salt or any combination thereof. In a specific embodiment, the ammonium salt includes organic ammonium salts such as ammonium benzenesulfonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate, inorganic ammonium salts such as ammonium sulfate, ammonium bicarbonate or any combination thereof. In another embodiment, the solvent is a hydrocarbon, a carbon-hydrogen-nitrogen compound, a carbon-hydrogen-oxygen-nitrogen compound or any combination thereof. In a specific embodiment, the solvent includes dimethylformamide, acetonitrile, N-methylpyrrolidone, cyclohexane or any combination thereof. In yet another embodiment, the substance capable of providing hydrogen protons includes liquid acid, solid acid or any combination thereof. In a specific embodiment, the substance capable of providing hydrogen protons includes liquid acid such as carbonic acid, benzenesulfonic acid, sulfuric acid, solid acid such as H-type molecular sieve, ion exchange resin or any combination thereof.

[0037] In one embodiment, the ionic liquid comprises cations and anions, the cations comprising quaternary ammonium salt ions, imidazolium salt ions, pyrrole salt ions, etc. or any combination thereof, and the anions comprising tetrafluoroborate ions, hexafluorophosphate ions or any combination thereof. In another embodiment, the protic ionic liquid comprises cations and anions, the cations comprising 1-alkyl imidazolium cations, primary ammonium cations, secondary ammonium cations, tertiary ammonium cations or any combination thereof, and the anions comprising carboxylates, trifluoroacetates, bis(perfluoroethylsulfonyl)imides, bis(trifluoromethanesulfonyl)imides, nitrates or any combination thereof.

[0038] In one embodiment, the first conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the first conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the first conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0039] In one embodiment, the second conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the second conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the second conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0040] In one embodiment, the first conductive portion is an anode for an electrolysis reaction, and the second conductive portion is a cathode for an electrolysis reaction. In another embodiment, the hydrogen production system further comprises a reference electrode. In yet another embodiment, the hydrogen production system further comprises a gas separation system. In a further embodiment, the gas separation system comprises a nitrogen permeable membrane and a hydrogen permeable membrane disposed in a product gas discharge portion.

[0041] In a third aspect, a power system is provided, comprising the hydrogen production system described herein. In one embodiment, the power system further comprises a gas storage tank and a hydrogen fuel cell, wherein the gas storage tank is connected to the gas ammonia / liquid ammonia feed section of the hydrogen production system, and the hydrogen fuel cell is connected to the product gas discharge section of the hydrogen production system. In another embodiment, the hydrogen production system comprises a gas ammonia / liquid ammonia feed section, a first conductive section, a second conductive section, an electrolysis section, and a product gas discharge section, wherein the electrolysis section comprises an electrolyte composition. For a gas ammonia system, the electrolyte composition contains an ammonium salt and a solvent that can dissolve the ammonium salt, and for a liquid ammonia system, the electrolyte is an ammonium salt.

[0042] In one embodiment, the electrolyte composition does not contain water. In another embodiment, the electrolyte composition further comprises an ionic liquid that is miscible with the solvent. In yet another embodiment, the ionic liquid is a protic ionic liquid. In a further embodiment, the electrolyte composition further comprises a substance that can provide hydrogen protons.

[0043] In one embodiment, the ammonium salt is an organic ammonium salt, an inorganic ammonium salt or any combination thereof containing ammonium ions. In a specific embodiment, the ammonium salt includes ammonium benzenesulfonate, ammonium sulfate, ammonium bicarbonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate or any combination thereof. In another embodiment, the solvent is a hydrocarbon, a carbon hydrogen nitrogen compound, a carbon hydrogen oxygen nitrogen compound or any combination thereof. In a specific embodiment, the solvent includes dimethylformamide, acetonitrile, N-methylpyrrolidone, cyclohexane or any combination thereof. In yet another embodiment, the substance capable of providing hydrogen protons includes liquid acid, solid acid or any combination thereof. In a specific embodiment, the substance capable of providing hydrogen protons includes H-type molecular sieve, ion exchange resin, carbonic acid, benzenesulfonic acid, sulfuric acid or any combination thereof.

[0044] In one embodiment, the ionic liquid comprises cations and anions, the cations comprising quaternary ammonium salt ions, imidazolium salt ions, pyrrole salt ions, etc. or any combination thereof, and the anions comprising tetrafluoroborate ions, hexafluorophosphate ions or any combination thereof. In another embodiment, the protic ionic liquid comprises cations and anions, the cations comprising 1-alkyl imidazolium cations, primary ammonium cations, secondary ammonium cations, tertiary ammonium cations or any combination thereof, and the anions comprising carboxylates, trifluoroacetates, bis(perfluoroethylsulfonyl)imides, bis(trifluoromethanesulfonyl)imides, nitrates or any combination thereof.

[0045] In one embodiment, the first conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the first conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the first conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0046] In one embodiment, the second conductive portion is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof, or any alloy thereof. In another embodiment, the second conductive portion undergoes a surface treatment selected from electroplating, coating, coating, surface modification, or any combination thereof. In yet another embodiment, the second conductive portion is sheet-shaped, disc-shaped, filament-shaped, or U-shaped.

[0047] In one embodiment, the first conductive portion is an anode for an electrolysis reaction, and the second conductive portion is a cathode for an electrolysis reaction. In another embodiment, the hydrogen production system further comprises a reference electrode. In yet another embodiment, the hydrogen production system further comprises a gas separation system. In a further embodiment, the gas separation system comprises a nitrogen permeable membrane and a hydrogen permeable membrane disposed in a product gas discharge portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The accompanying drawings are provided to further illustrate the technical solutions and implementations illustrated in this document, but the accompanying drawings are only for those skilled in the art to further understand the contents of the present invention and are not intended to limit the scope of the present invention.

[0049] Figure 1 It is a schematic diagram of the device for preparing hydrogen by electrolyzing ammonia in the embodiments and comparative examples of the present invention.

[0050] Figure 2 It is a current-time curve of the electrolysis reaction of Example 1 of the present invention.

[0051] Figure 3 It is a current-time curve of the electrolysis reaction of Comparative Example 1 of the present invention.

[0052] Figure 4 It is a current-time curve of the electrolysis reaction of Example 2 of the present invention.

[0053] Figure 5 It is the current-time curve of the electrolysis reaction of Example 3 of the present invention.

[0054] Figure 6 It is a current-time curve of the electrolysis reaction of Example 4 of the present invention. DETAILED DESCRIPTION

[0055] Hereinafter, the concept of the present invention will be further described from the specific embodiments. The specific embodiments listed below are only examples, not limiting the scope of the present disclosure. Those skilled in the art will recognize that the specific features in any of the following embodiments can be used in any other embodiment, as long as they do not violate the concept of the present invention.

[0056] The hydrogen production system of the present invention includes a gaseous ammonia / liquid ammonia feed section (e.g., a gaseous ammonia feed section), a first conductive section, a second conductive section, an electrolysis section, and a product gas discharge section. The gaseous ammonia / liquid ammonia feed section refers to an inlet for introducing gaseous ammonia or liquid ammonia or both, and may be a gaseous ammonia / liquid ammonia inlet connected to a storage tank for storing ammonia gas or liquid ammonia. The product gas discharge section may be a product gas outlet for discharging nitrogen and hydrogen, respectively. The gaseous ammonia / liquid ammonia feed section is connected to the electrolysis section, and the first conductive section and the second conductive section are wholly or partially placed in the electrolysis section (e.g., Figure 1 shown).

[0057] The electrolysis unit may be an electrolytic cell and include an electrolyte composition. The electrolyte composition may contain an ammonium salt and a solvent that can dissolve the ammonium salt, or may be composed of an ammonium salt and a solvent that can dissolve the ammonium salt. Here, the solvent refers to a non-aqueous solvent. The electrolyte composition preferably does not contain water. In addition, the electrolyte composition may further include an ionic liquid that is miscible with the solvent. The ionic liquid may be a proton ionic liquid. The electrolyte composition may also include a substance that can provide hydrogen protons.

[0058] By applying a voltage difference to the conductive part (e.g., electrode) of the hydrogen production system of the present invention, ammonia is electrolyzed to produce hydrogen and nitrogen, wherein the voltage difference is sufficient to achieve electrolysis of ammonia in the electrolyte composition to produce hydrogen and nitrogen. For example, by applying a certain voltage to the first conductive part and the second conductive part, ammonia introduced into the electrolytic cell from the gas ammonia / liquid ammonia feed port is decomposed to produce nitrogen and hydrogen. The first conductive part that complies with reaction formula (5) as the anode of the electrolysis reaction is the location where nitrogen is produced, that is, the working electrode of the electrolytic cell. The second conductive part that complies with reaction formula (6) as the cathode of the electrolysis reaction is the location where hydrogen is produced, that is, the auxiliary electrode of the electrolytic cell. In addition, a reference electrode can be used as a reference for the electrode reaction.

[0059] It is believed that the electrode area of ​​the second conductive part is larger than that of the first conductive part, so that it is not easily polarized during the test. The electrolyte composition added to the electrolytic part provides a certain amount of NH4 for the reaction. + Ions increase the conductivity of the system and promote the reaction.

[0060] The ammonium salt used in the present invention includes ammonium benzenesulfonate, ammonium sulfate, ammonium bicarbonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate or any combination thereof. The solvent that can dissolve the ammonium salt can include dimethylformamide, acetonitrile, N-methyl pyrrolidone, cyclohexane or any combination thereof. The material that can provide hydrogen protons can include H-type molecular sieve, ion exchange resin, carbonic acid, benzenesulfonic acid, sulfuric acid or any combination thereof.

[0061] The ionic liquid used in the present invention can include cations and anions, wherein the cations include quaternary ammonium salt ions, imidazolium salt ions, pyrrole salt ions, etc. or any combination thereof, and the anions include tetrafluoroborate ions, hexafluorophosphate ions or any combination thereof. In addition, the ionic liquid can be a proton type ionic liquid. The proton type ionic liquid can include cations and anions, wherein the cations include 1-alkyl imidazolium cations, primary ammonium cations, secondary ammonium cations, tertiary ammonium cations or any combination thereof, and the anions include carboxylate, trifluoroacetate, bis(perfluoroethylsulfonyl)imide, bis(trifluoromethanesulfonyl)imide, nitrate or any combination thereof.

[0062] For the electrolyte composition described in this article, one or more of dimethylformamide (hereinafter referred to as DMF), acetonitrile, N-methylpyrrolidone, cyclohexane, etc. can be used and mixed with one or more of ionic liquids composed of cations such as quaternary ammonium ions, imidazolium ions, pyrrole ions, etc. and anions such as tetrafluoroborate ions and hexafluorophosphate ions in a certain proportion, for example, in a volume ratio of 1:10 to 10:1.

[0063] The first conductive part used in the present invention can include carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof or any alloy, for example, made of these materials. The first conductive part can further undergo surface treatment, such as electroplating, coating, coating, surface modification or any other suitable treatment to prevent deactivation during the reaction process. The first conductive part can be in any suitable shape, such as sheet, disc, filament or U-shaped.

[0064] The second conductive part used in the present invention can include carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof or any alloy, for example, made of these materials. The second conductive part can further undergo surface treatment, such as electroplating, coating, coating, surface modification or any other suitable treatment to prevent deactivation during the reaction process. The second conductive part can be in any suitable shape, such as sheet, disc, filament or U-shaped.

[0065] The hydrogen production system of the present invention may further include a gas separation system. The gas separation system may include a nitrogen permeable membrane and a hydrogen permeable membrane disposed at the product gas discharge portion. For example, the nitrogen permeable membrane and the hydrogen permeable membrane may be disposed at the gas product outlet near the auxiliary electrode and the gas product outlet near the working electrode, respectively, to selectively obtain hydrogen.

[0066] The hydrogen production method of the present invention comprises generating hydrogen using the hydrogen production system described above; and collecting and storing the generated hydrogen. The hydrogen production method is a hydrogen production method by electrolyzing ammonia, and can be implemented at room temperature.

[0067] The power system of the present invention includes the hydrogen production system described above, and may also include a gas storage tank and a hydrogen fuel cell, wherein the gas storage tank is connected to the gaseous ammonia / liquid ammonia feed part of the hydrogen production system, and the hydrogen fuel cell is connected to the product gas discharge part of the hydrogen production system.

[0068] Example

[0069] The following examples are provided to facilitate a better understanding of the embodiments of the present disclosure, but are not intended to be limiting. Unless otherwise specified in the following examples, the operation and detection methods are conventional methods, and the reagents and materials can be obtained by conventional means.

[0070] Gas chromatography (GC) detection

[0071] The gas chromatograph described in this article is an Agilent 490 micro gas chromatograph, and a 10mMS5A column is used for qualitative and quantitative analysis of gas products. The retention time of gas products is qualitatively analyzed using standard gas, and the curve of standard gas peak area and standard gas concentration is drawn using the external standard method to quantitatively analyze the gas products, and an analysis system for evaluating electrolysis efficiency is established.

[0072] The chromatographic column detection conditions are as follows: injector temperature 70°C, column temperature 40°C, initial pressure 150.0 KPa, and according to the different gas thermal conductivities (10 -5 W / (m·K)), and argon was selected as the carrier gas.

[0073] Table 1

[0074] <![CDATA[N2]]> <![CDATA[H2]]> Ar He 0℃ 0.24 1.75 0.17 1.46 100℃ 0.32 2.24 0.22 1.75

[0075] Evaluation Method of Hydrogen Production System by Ammonia Electrolysis

[0076] A certain amount of ammonia is introduced into an ammonia electrolysis cell containing an electrolyte composition. A three-electrode electrolysis system is adopted. A certain voltage / current is applied to the first conductive part (working electrode). Under different conditions, the efficiency of hydrogen production by ammonia electrolysis is evaluated by the following formula based on the concentration of H2 [C(H2)] and N2 [C(N2)] at the outlet.

[0077] Faraday efficiency of H2 η(H2) = [outlet H2 concentration (%) × gas volume (L) × 96485 × 2 / 24.5] / [current (A) × time (s)]

[0078] Faraday efficiency of N2 η(N2) = [outlet N2 concentration (%) × gas volume (L) × 96485 × 6 / 24.5] / [current (A) × time (s)]

[0079] Electrode treatment

[0080] The surfaces of the Pt working electrode (7.5×10×0.1 mm) and the auxiliary electrode (10×10×0.2 mm) were polished with metallographic sandpaper and ultrasonicated in ethanol, potassium hydroxide, sulfuric acid solution and deionized water for 20 min in turn to remove impurities on the electrode surface, and then dried for use.

[0081] A certain amount of AgNO3 and tetrabutylammonium acetate were dissolved in DMF to make the concentrations of 10mM and 0.1M respectively. The solution was filled in a reference electrode with a diameter of 6mm and the silver wire was completely immersed in the solution to obtain a silver ion electrode. Under open circuit potential, two prepared silver ion electrodes were used as working electrode and auxiliary electrode respectively to ensure that the potential fluctuation was less than 10mV within 10min, indicating that the silver ion reference electrode was stable and could be used normally.

[0082] Example 1

[0083] 0.70 g of ammonium benzenesulfonate was dissolved in 80 mL of DMF and stirred to obtain an electrolyte composition, wherein the molar concentration of ammonium benzenesulfonate was 0.05 M. The stirred electrolyte composition was placed in an electrolytic cell. 10% ammonia (Ar was the balance gas) was allowed to enter the electrolytic cell from the ammonia inlet (i.e., the ammonia feed section) at a certain flow rate and the pressure in the electrolytic cell reached 1.5 MPa.

[0084] The electrolyte composition is allowed to absorb ammonia gas under stirring until the pressure in the electrolytic cell is constant, and a constant voltage of 0.9 V is applied to the electrolytic cell for 10 hours. The current-time curve is as follows: Figure 2 The gas in the electrolytic cell was passed into the gas chromatograph at a certain flow rate, and the chromatographic detection results are shown in Table 2.

[0085] Comparative Example 1

[0086] 0.70 g of ammonium benzenesulfonate was dissolved in 80 mL of DMF and stirred to obtain an electrolyte composition, wherein the molar concentration of ammonium benzenesulfonate was 0.05 M. The stirred electrolyte composition was placed in an electrolytic cell, and argon (99.99%) was allowed to enter the electrolytic cell from the ammonia inlet at a certain flow rate and the pressure in the electrolytic cell reached 1.5 MPa.

[0087] The electrolyte composition is allowed to absorb argon gas under stirring until the pressure in the electrolytic cell is constant, and a constant voltage of 0.9 V is applied to the electrolytic cell for 2 h. The current-time curve is as follows: Figure 3 The gas in the electrolytic cell was passed into a gas chromatograph at a certain flow rate, and no hydrogen and nitrogen products were analyzed by chromatographic detection.

[0088] Example 2

[0089] 0.70 g of ammonium benzenesulfonate was dissolved in 80 mL of DMF, and then 0.95 mL of [Bmim][PF6] (1-butyl-3-methylimidazolium hexafluorophosphate) was added and stirred to obtain an electrolyte composition, wherein the molar concentration of ammonium benzenesulfonate was 0.05 M. The stirred electrolyte composition was placed in an electrolytic cell. 10% ammonia (Ar was the balance gas) was allowed to enter the electrolytic cell from the ammonia inlet at a certain flow rate and the pressure in the electrolytic cell reached 1.5 MPa.

[0090] The electrolyte composition is allowed to absorb ammonia gas under stirring until the pressure in the electrolytic cell is constant, and a constant voltage of 0.9 V is applied to the electrolytic cell for 10 hours. The current-time curve is as follows: Figure 4 The gas in the electrolytic cell was passed into the gas chromatograph at a certain flow rate, and the chromatographic detection results are shown in Table 2.

[0091] Example 3

[0092] 0.70 g of ammonium benzenesulfonate was dissolved in 76.2 mL of DMF, and then 3.8 mL of [Bmim][PF6] was added and stirred to obtain an electrolyte composition, wherein the molar concentration of ammonium benzenesulfonate was 0.05 M. The stirred electrolyte composition was placed in an electrolytic cell, and 10% ammonia (Ar was the balance gas) was allowed to enter the electrolytic cell from the ammonia inlet at a certain flow rate and the pressure in the electrolytic cell reached 1.5 MPa.

[0093] The electrolyte composition is allowed to absorb ammonia gas under stirring until the pressure in the electrolytic cell is constant, and a constant voltage of 0.9 V is applied to the electrolytic cell for 10 hours. The current-time curve is as follows: Figure 5 The gas in the electrolytic cell was passed into the gas chromatograph at a certain flow rate, and the chromatographic detection results are shown in Table 2.

[0094] Example 4

[0095] 1.20 g of tetrabutylammonium acetate was dissolved in 80 mL of DMF and stirred to obtain an electrolyte composition, wherein the molar concentration of tetrabutylammonium acetate was 0.05 M. The stirred electrolyte composition was placed in an electrolytic cell. 10% ammonia (Ar was the balance gas) was allowed to enter the electrolytic cell from the ammonia inlet at a certain flow rate and the pressure in the electrolytic cell reached 1.5 MPa.

[0096] The electrolyte composition is allowed to absorb ammonia gas under stirring until the pressure in the electrolytic cell is constant, and a constant voltage of 0.9 V is applied to the electrolytic cell for 10 hours. The current-time curve is as follows: Figure 6 The gas in the electrolytic cell was passed into the gas chromatograph at a certain flow rate, and the chromatographic detection results are shown in Table 2.

[0097] Table 2

[0098] <![CDATA[η(H2)(%)]]> <![CDATA[η(N2)(%)]]> <![CDATA[c(H2):c(N2)]]> Example 1 55.08 54.32 3.04 Comparative Example 1 0 0 / Example 2 84.46 90.45 2.87 Example 3 69.95 84.01 2.50 Example 4 63.56 70.93 2.69

[0099] From the results of the above embodiments and comparative examples, it can be seen that when ammonia is introduced, nitrogen and hydrogen are detected in the product, and the c(H2):c(N2) is close to 3:1, which proves that an ammonia conversion reaction occurs in the electrolysis system, and the reaction proceeds according to reaction equations (5) and (6).

[0100] Although the embodiments described herein have been described in detail with reference to specific examples and comparative examples, those skilled in the art will appreciate that various modifications and changes may be made without departing from the scope and spirit of the present disclosure.

Claims

1. A hydrogen production system, comprising an ammonia gas feed section, a first conductive section, a second conductive section, an electrolysis section and a product gas discharge section, wherein the electrolysis section comprises an electrolyte composition, the electrolyte composition comprises an ammonium salt, a solvent capable of dissolving the ammonium salt and an ionic liquid miscible with the solvent, wherein: The ammonium salt is selected from ammonium benzenesulfonate, ammonium sulfate, ammonium bicarbonate, ammonium acetate, ammonium laurate, tetrabutylammonium acetate or any combination thereof, the solvent is dimethylformamide, the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, the ammonium salt is 0.7 g, the dimethylformamide is 80 ml, and the 1-butyl-3-methylimidazolium hexafluorophosphate is 0.95 mL.

2. The hydrogen production system according to claim 1, wherein the electrolyte composition does not contain water, and / or The electrolyte composition also includes a substance capable of donating hydrogen protons. 3 . The hydrogen production system according to claim 2 , wherein the substance capable of providing hydrogen protons comprises a liquid acid, a solid acid or any combination thereof.

4. The hydrogen production system according to claim 2, wherein the substance capable of providing hydrogen protons comprises H-type molecular sieve, ion exchange resin, carbonic acid, benzenesulfonic acid, sulfuric acid or any combination thereof.

5. The hydrogen production system according to claim 1 or 2, wherein the first conductive part is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof or any alloy thereof, and The second conductive part is made of carbon, cobalt, copper, iridium, iron, nickel, palladium, platinum, rhodium, ruthenium, manganese, silver, gold, any combination thereof or any alloy thereof. 6 . The hydrogen production system according to claim 1 , wherein the first conductive portion is an anode for electrolysis reaction, and the second conductive portion is a cathode for electrolysis reaction.

7. The hydrogen production system according to claim 1 or 2, further comprising a reference electrode and / or a gas separation system, wherein the gas separation system comprises a nitrogen permeable membrane and a hydrogen permeable membrane disposed at the product gas discharge section.

8. A method for producing hydrogen, comprising generating hydrogen using the hydrogen production system according to any one of claims 1 to 7; and collecting and storing the generated hydrogen.

9. A power system comprising the hydrogen production system according to any one of claims 1 to 7, wherein the power system optionally further comprises a gas storage tank and a hydrogen fuel cell, wherein the gas storage tank is connected to the ammonia feed part of the hydrogen production system, and the hydrogen fuel cell is connected to the product gas discharge part of the hydrogen production system.

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