Electrolytic cell for producing hydrogen by electrolysis of water, method for producing hydrogen by electrolysis of water

Abstract

The application provides a water electrolysis hydrogen production electrolytic cell and a water electrolysis hydrogen production method. The water electrolysis hydrogen production electrolytic cell is provided with an anode, a cathode, a diaphragm, an anode flow channel, a storage device and an electrolyte conveying device. The electrolyte inlet of the electrolyte conveying device is communicated with the electrolyte outlet of the storage device, the electrolyte outlet of the electrolyte conveying device is communicated with the electrolyte inlet of the anode flow channel, and the electrolyte outlet of the anode flow channel is communicated with the electrolyte inlet of the storage device. The electrolyte containing the dispersed anode catalyst is circulated and flowed in the anode flow channel and the storage device, so that the polarization performance and the stability of the water electrolysis hydrogen production electrolytic cell during the water electrolysis hydrogen production are significantly improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of hydrogen production by water electrolysis, and particularly relates to a hydrogen production by water electrolysis electrolytic tank and a hydrogen production by water electrolysis method. BACKGROUND

[0002] Hydrogen energy is an important part of the future national energy system, and efficient and low-cost hydrogen production is a necessary prerequisite for the large-scale application of hydrogen energy. Water electrolysis hydrogen production technology is an important way for large-scale green hydrogen production. Among them, ion exchange membrane water electrolysis, including alkaline water electrolysis (ALK), proton exchange membrane water electrolysis (PEMWE) and anion exchange membrane water electrolysis (AEMWE), has a wide application prospect in water electrolysis hydrogen production technology. Among them, membrane electrode (MEAs) is the core component of ion exchange membrane water electrolysis device, which is composed of cathode and anode catalyst layers (Catalyst Layers, CLs), gas diffusion layers (Gas Diffusion Layers, GDLs) and separators. Hydrogen evolution reaction (HER) or oxygen evolution reaction (OER) half-reaction in water electrolysis occurs on CLs, and CLs plays an important role in the performance of membrane electrode. (Energy Chem, 2022, 4(5): 100087; Chemical Society Reviews, 2022, 51(23): 9620-93).

[0003] Currently, the preparation methods of catalysts in CLs layer mainly include two kinds of powder catalyst preparation and self-supporting catalyst preparation. Powder catalysts can be combined with ionomers to prepare CLs by ultrasonic spraying or transfer printing methods. The use of ionomers in the catalyst layer limits the exposure of catalyst active sites and the mass transfer of gaseous products (O2 and H2) in electrochemical reactions. In addition, most ionomers are composed of unstable phenyl skeletons, which are easily oxidized at high working cell voltage (>2.1V), thereby causing a decrease in local pH at the electrode-electrolyte interface, affecting the overall performance of the battery. (Energy & Environmental Science, 2023, 16(10): 4373-87). Self-supporting catalysts can avoid the use of ionomers, avoiding the problem of degradation of ionomers affecting the stability of electrolytic tank operation. However, it will face serious problems of catalyst stacking, falling off and dissolution, which will lead to the failure of the catalyst layer, and the catalyst utilization efficiency is low. (ACS Energy Letters, 2023, 8(8): 3330-42).

[0004] In general, in the traditional catalyst use mode, the catalyst material is adhered to the electrode surface, and then immersed in the electrolyte and subjected to long-term, continuous electrochemical reactions. However, due to the high-voltage, large-current environment, H + or OH - The presence of attack and diffusion-induced stress (collectively referred to as "electrocatalytic stress") can cause catalyst poisoning, agglomeration, dissolution, sintering, and other phenomena during long-term operation, resulting in catalyst "fatigue" or even deactivation, and leading to a decline in the overall performance of the membrane electrode.

[0005] To address the above problems, the traditional strategy is to start from the catalyst itself, and to control the surface state and chemical composition by surface morphology control, alloying, doping, heterojunction construction, or mechanical strain adjustment, to improve the stability of the catalyst while maintaining the activity of the catalyst. (Science 2014, 343(6177), 1339-1343; ACS Nano 2012, 6(6), 5642-5647). For example, Koshikawa et al. synthesized NiFe-LDH nanoparticles with a lateral size of less than 10 nm using a sol-gel method, used it as an anode catalyst, combined Nafion as an ionomer, and used an ultrasonic spray coating method to prepare the catalyst layer, and assembled a membrane electrode device. The electrolysis voltage was only 1.59 V at a current density of 1 A cm -2 The performance was superior to that of the noble metal catalyst IrO x (1.61 V) (ACS Catalysis, 2020, 10(3): 1886-93), but because the catalyst can "fatigue" or undergo irreversible phase transition during long-term operation, the stability of the membrane electrode is poor and the performance decays quickly.

[0006] In summary, the powder catalyst combined with the catalyst layer prepared by ionomer may block the active sites; the self-supporting catalyst layer may have problems such as catalyst stacking, falling off and dissolving. The catalyst layer prepared by the traditional method has the problem of insufficient utilization of active sites. In the electrocatalytic reaction, the reactants need to complete the complex process of adsorption, conversion and desorption on the catalyst surface. The mass transfer limitation is an important factor causing the slow reaction rate. The catalyst fixed on the gas diffusion layer may gradually undergo irreversible phase change, falling off, poisoning and other phenomena during use, thereby deactivating and causing the performance of the membrane electrode to decay. The catalyst layer prepared by the traditional method has the problem of poor long-term cycle stability caused by catalyst deactivation. Since the catalyst fatigue or deactivation mechanisms are various, and the materials, components and structures of the catalyst and its carrier are different, the solution based on the catalyst material itself is often only applicable to a specific catalyst and does not have universality. In addition, the diffusion limitation of the reactive species to the catalyst surface also causes the catalytic current to decay, and the traditional catalyst modification strategy cannot change the diffusion limitation problem. In summary, only the modification of the morphology and intrinsic activity of the catalyst itself cannot meet the requirements of preparing a membrane electrode with high activity and stability, and a more effective and practical method is urgently needed.

[0007] How to find an ion exchange membrane water electrolysis hydrogen electrolyzer, a method for preparing a catalyst layer for water electrolysis hydrogen production to solve the problems of catalyst stacking, falling off and other problems caused by ionomer degradation in the catalyst layer, while improving the polarization performance and stability of the membrane electrode is a technical problem to be solved at present. SUMMARY

[0008] In view of the above problems, the present application provides a water electrolysis hydrogen electrolyzer and a method for water electrolysis hydrogen production.

[0009] In one aspect, the present application provides a water electrolysis hydrogen electrolyzer, which comprises:

[0010] an anode,

[0011] a cathode,

[0012] a diaphragm,

[0013] an anode flow channel,

[0014] a storage device for storing an electrolyte in which an anode catalyst is dispersed, and

[0015] an electrolyte delivery device.

[0016] The electrolyte inlet of the electrolyte delivery device is in communication with the electrolyte outlet of the storage device, the electrolyte outlet of the electrolyte delivery device is in communication with the electrolyte inlet of the anode flow channel, and the electrolyte outlet of the anode flow channel is in communication with the electrolyte inlet of the storage device.

[0017] In another aspect, the present application provides a method for electrolysis of water to produce hydrogen, which is performed in the electrolysis cell for electrolysis of water to produce hydrogen described above, wherein the electrolysis cell is provided with:

[0018] an anode,

[0019] a cathode,

[0020] a diaphragm,

[0021] an anode flow channel,

[0022] a storage device for storing electrolyte in which the anode catalyst is dispersed, and

[0023] an electrolyte delivery device.

[0024] In the method, the electrolyte delivery device circulates the electrolyte in which the anode catalyst is dispersed in the anode flow channel and the storage device.

[0025] In the method, the electrolyte delivery device circulates the electrolyte in which the anode catalyst is dispersed in the anode flow channel and the storage device.

[0026] Advantages:

[0027] (1) The present application sends the catalyst into the membrane electrode flow channel with the electrolyte, which contacts the gas diffusion layer and catalyzes the water electrolysis reaction. The catalyst with high dispersion and circulation has more available active sites, avoids catalyst stacking, and solves the problem of insufficient utilization of active sites of the catalyst prepared by the traditional method.

[0028] (2) The catalyst flows with the electrolyte, which couples the electron transfer reaction with other slow steps (such as adsorption, desorption, and mass transfer reaction) in time and space scales, increases the diffusion rate of H + or OH - to the catalyst surface in the OER reaction, and solves the problem of mass transfer limitation under high current density.

[0029] (3) The working mode of the catalyst is changed to rotation and intermittence, which reduces the “electrocatalytic stress” received by the catalyst, avoids catalyst peeling and sintering, and solves the problem of poor long-term stability of the catalyst.

[0030] (4) The present application circulates the electrolyte in which the anode catalyst is dispersed in the anode flow channel and the storage device, which significantly improves the polarization performance and stability of the electrolysis cell for electrolysis of water to produce hydrogen during the electrolysis of water to produce hydrogen.

[0031] (5) The circulating catalyst can be conveniently recycled and reused, which reduces the preparation cost of the anode catalyst layer and further reduces the cost of the electrolysis of water to produce hydrogen technology. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic diagram of an embodiment of the electrolysis cell for electrolysis of water to produce hydrogen of the present application.

[0033] Figure 2 A physical diagram of an embodiment of an electrolytic cell for producing hydrogen by electrolysis of water according to the present invention;

[0034] Figure 3 This is a schematic structural diagram of an embodiment of a Martens flask in an electrolytic cell for producing hydrogen by electrolysis of water according to the present invention;

[0035] Figure 4 This is a schematic structural diagram of an embodiment of a blue-cap bottle in an electrolytic cell for producing hydrogen by electrolysis of water according to the present invention;

[0036] Figure 5 and Figure 6 The polarization curve and stability curve obtained in Test Example 1 of the present invention;

[0037] Figure 7 This is the polarization curve obtained in Test Example 2 of the present invention;

[0038] Figure 8 and Figure 9 These are the polarization curves and stability curves obtained in Test Example 3 of the present invention;

[0039] Figure 10 and Figure 11 These are the polarization curves and stability curves obtained in Test Example 4 of the present invention;

[0040] Description of Reference Numerals

[0041] 1. Anode; 2. Cathode; 3. Diaphragm; 4. Anode flow channel;

[0042] 5. Storage device; 6. Electrolyte delivery device;

[0043] 11 air outlet; 12 liquid inlet; 13 fixing screw; 14 Martens flask body;

[0044] 15. Liquid outlet; 16. Tripod. DETAILED DESCRIPTION

[0045] The present application will be further described in detail below through the accompanying drawings and examples, through which the features and advantages of the present application will become more clear and distinct.

[0046] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0047] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] In one aspect, the present application provides a water electrolysis hydrogen production electrolyzer, as shown in Figure 1 、 Figure 2 which is provided with:

[0049] an anode 1,

[0050] a cathode 2,

[0051] a diaphragm 3,

[0052] an anode flow channel 4,

[0053] a storage device 5 for storing electrolyte in which an anode catalyst is dispersed, and

[0054] an electrolyte conveying device 6.

[0055] In the present application, the electrolyte inlet of the electrolyte conveying device 6 is in communication with the electrolyte outlet of the storage device 5, the electrolyte outlet of the electrolyte conveying device 6 is in communication with the electrolyte inlet of the anode flow channel 4, and the electrolyte outlet of the anode flow channel 4 is in communication with the electrolyte inlet of the storage device 5.

[0056] It should be noted that in the water electrolysis hydrogen production electrolyzer of the present application, the storage device 5 stores electrolyte in which an anode catalyst is dispersed, and the electrolyte conveying device 6 is connected between the storage device 5 and the anode flow channel 4. The electrolyte conveying device 6 circulates the electrolyte in which the anode catalyst is dispersed stored in the storage device 5 between the storage device 5 and the anode flow channel 4. Specifically, the electrolyte conveying device 6 first causes the electrolyte in which the anode catalyst is dispersed to flow out of the storage device 5, flow into the anode flow channel 4 through the electrolyte conveying device 6, then flow from the anode flow channel 4 into the storage device 5, and then flow from the storage device 5 into the anode flow channel 4 through the electrolyte conveying device 6, and so on. In the process of circulating flow, the anode catalyst is always in a state of circulating flow with the electrolyte.

[0057] In the water electrolysis hydrogen production electrolyzer of the present application, the anode catalyst is dispersed in the electrolyte to perform an anode catalytic reaction in a flow manner, avoiding catalyst stacking, sintering and falling off, and the active sites of the catalyst can be more fully utilized, and the diffusion rate and mass transfer rate of H + or OH - to the surface of the catalyst in the OER reaction are increased. In particular, the electrolyte conveying device 6 circulates the electrolyte in which the anode catalyst is dispersed stored in the storage device 5 between the storage device 5 and the anode flow channel 4, which can further increase the mass transfer rate and enhance the stability of the catalyst, and the polarization performance and stability of the water electrolysis hydrogen production electrolyzer are further significantly improved.

[0058] In one embodiment of the water electrolysis cell for hydrogen production of the present application, the anode 1 comprises a first gas diffusion layer, which is arranged on the anode side of the diaphragm 3, and no anode catalyst layer is arranged on the first gas diffusion layer;

[0059] The cathode 2 comprises a second gas diffusion layer, which is arranged on the cathode side of the diaphragm 3.

[0060] The second gas diffusion layer is arranged with or without a cathode catalyst layer.

[0061] It should be noted that in this embodiment, the first gas diffusion layer is not arranged with an anode catalyst layer, and the anode catalyst is dispersed in the electrode liquid and circulated between the anode flow channel and the storage device. When the second gas diffusion layer is arranged with a cathode catalyst layer, the cathode can be supplied with or without electrolyte, and the water electrolysis process can be well carried out. Alternatively, when the second gas diffusion layer is not arranged with a cathode catalyst layer, the cathode needs to be supplied with electrolyte dispersed with a cathode catalyst, and the anode and cathode of the electrolysis cell are both flow-type catalyst catalytic reactions. These specific embodiments can well carry out the water electrolysis process for hydrogen production and achieve good polarization performance and stability.

[0062] In another embodiment of the water electrolysis cell for hydrogen production of the present application, the water electrolysis cell for hydrogen production further comprises:

[0063] a cathode flow channel,

[0064] a cathode storage device for storing electrolyte or electrolyte dispersed with a cathode catalyst, and

[0065] a cathode electrolyte delivery device.

[0066] The electrolyte inlet of the cathode electrolyte delivery device is in communication with the electrolyte outlet of the cathode storage device, the electrolyte outlet of the cathode electrolyte delivery device is in communication with the electrolyte inlet of the cathode flow channel, and the electrolyte outlet of the cathode flow channel is in communication with the electrolyte inlet of the cathode storage device.

[0067] It should be noted that in the water electrolysis hydrogen production electrolytic cell of the present application, in the implementation mode in which the cathode is connected or not connected with the electrolyte, the cathode can be provided with a cathode flow channel, so that the electrolytic cell has good versatility and can be used when the cathode is connected or not connected with the electrolyte. Specifically, when the second gas diffusion layer is provided with a cathode catalyst layer, at this time the cathode storage device can store the electrolyte (without dispersing the cathode catalyst), and the cathode electrolyte conveying device makes the electrolyte in the cathode storage device circulate between the cathode flow channel and the cathode storage device; or when the second gas diffusion layer is not provided with a cathode catalyst layer, at this time the cathode storage device stores the electrolyte dispersed with the cathode catalyst, and the cathode electrolyte conveying device makes the electrolyte dispersed with the cathode catalyst in the cathode storage device circulate between the cathode flow channel and the cathode storage device.

[0068] In another embodiment of the above-mentioned water electrolysis hydrogen production electrolytic cell of the present application, the storage device 5 is provided with a stirring component, or the storage device 5 is a marvian bottle.

[0069] It should be noted that when the storage device 5 is a marvian bottle, the electrolyte dispersed with the anode catalyst stored in the marvian bottle does not need to be stirred, but when the storage device 5 is a general storage bottle, a stirring component needs to be provided to stir the electrolyte dispersed with the anode catalyst stored therein. The stirring component can be a magnetic stirring component, a stirring rod, or any component that can stir liquid.

[0070] In one embodiment of the above-mentioned water electrolysis hydrogen production electrolytic cell of the present application, as shown in Figure 3 The marvian bottle is provided with a marvian bottle body 14, a bottle cap, and a foot stand 16; the bottle cap is connected to the top opening of the marvian bottle body 14 by a fixing screw 13, and the bottle cap is provided with a gas outlet 11 and a liquid inlet 12; the bottom of the bottle body 14 is hemispherical, and the lowest part of the bottom of the bottle body 14 is provided with a liquid outlet 15; the foot stand 16 is connected to the lower part of the bottle body 14.

[0071] It should be noted that the marvian bottle used in the present application is generally used as an elution bottle. The present inventors have found that the non-noble metal Ni, Fe, Co catalyst with magnetism cannot be stirred by magnetic stirring, and therefore the marvian bottle is redesigned to store the electrolyte dispersed with the anode catalyst. The redesigned marvian bottle is as shown in Figure 3The catalyst can be gathered at the liquid outlet 15 after the catalyst is settled, the electrolyte mixed with the catalyst flows out from the liquid outlet 15, and the electrolyte flows back into the bottle from the liquid inlet 12 after passing through the electrolytic cell, and then the catalyst can be dispersed in the electrolyte again to form a cycle. Under the action of the electrolyte conveying device, the electrolyte with the dispersed anode catalyst in the Mars bottle circulates in the anode flow channel and the Mars bottle. The electrolyte flows out from the lower end of the bottle, and the catalyst deposited at the bottom of the bottle enters the pipeline and the flow channel of the electrode plate. The catalyst can flow with the electrolyte without the aid of stirring components. At this time, the electrolytic cell for producing hydrogen by electrolysis of water can exhibit better polarization performance.

[0072] In an embodiment of the electrolytic cell for producing hydrogen by electrolysis of water, the electrolyte conveying device 6 is selected from a peristaltic pump, a diaphragm pump, a reciprocating pump or a centrifugal pump. Alternatively, it can also be other liquid conveying equipment.

[0073] It should be noted that the above-mentioned peristaltic pump, diaphragm pump, reciprocating pump, centrifugal pump and the like as the electrolyte conveying device can enable the electrolyte with the dispersed anode catalyst to circulate at a stable flow rate between the storage device and the anode flow channel, and the electrolytic cell for producing hydrogen by electrolysis of water can operate stably and efficiently.

[0074] In an embodiment of the electrolytic cell for producing hydrogen by electrolysis of water, the electrolyte inlet and the electrolyte outlet of the anode flow channel 4 are respectively arranged at the lower end and the upper end thereof.

[0075] It should be noted that as a preferred embodiment, the storage device is a Mars bottle, and the liquid is discharged from the lower end and the liquid is introduced from the upper end, which can prevent the anode catalyst accumulated at the bottom of the bottle from being utilized to a certain extent. The electrolyte with the dispersed anode catalyst can better circulate between the anode flow channel and the Mars bottle, and the anode catalyst can be more fully utilized. At the same time, the anode flow channel has the liquid introduced from the lower end and the liquid discharged from the upper end, which can further improve the stability of the electrolyte with the dispersed anode catalyst during the flow process in the anode flow channel, so as to further improve the stability of the electrolytic cell.

[0076] In an embodiment of the electrolytic cell for producing hydrogen by electrolysis of water, the separator 3 is selected from an anion exchange membrane, a proton exchange membrane, an ionic solvent membrane or an alkaline electrolysis water separator.

[0077] It should be noted that the electrolytic cell for producing hydrogen by electrolysis of water has wide applicability. The separator can be the above-mentioned various membrane layers, and can also be used in other fields of liquid-phase electrocatalysis and flow batteries.

[0078] On the other hand, the present application provides a method for producing hydrogen by electrolysis of water, which is carried out in the above-mentioned electrolytic cell for producing hydrogen by electrolysis of water, and the electrolytic cell for producing hydrogen by electrolysis of water is provided with:

[0079] an anode 1,

[0080] a cathode 2,

[0081] a separator 3,

[0082] an anode flow channel 4,

[0083] a storage device 5 for storing electrolyte in which an anode catalyst is dispersed, and

[0084] an electrolyte delivery device 6;

[0085] The method comprises the following steps:

[0086] The electrolyte delivery device 6 circulates the electrolyte in which the anode catalyst is dispersed in the anode flow channel 4 and the storage device 5.

[0087] In the method for electrolyzing water to produce hydrogen according to the present application, a certain amount of anode catalyst is first ultrasonically dispersed in the electrolyte, and then the anode catalyst is delivered into the anode flow channel together with the electrolyte by the circulation feeding mode of the electrolyte delivery device, so that the powder solid catalyst is made to flow with the electrolyte. Then, the anode catalyst in the electrolyte is subjected to electron transfer, adsorption of H + or OH - , generation and transfer of O2 bubbles in the contact and collision with the anode gas diffusion layer, and plays a role of catalyzing the OER reaction. In the time and space scales, the electron transfer reaction is coupled with other slow steps (such as adsorption, desorption, mass transfer reaction), the mass transfer rate of H + or OH - is increased, and the OER reaction rate is improved. The transient Faraday current generated when a single catalyst particle collides with the gas diffusion layer can be accumulated, and then a continuous and stable current is output, so that the purpose of continuous and stable operation of the water electrolysis cell for electrolyzing water to produce hydrogen is achieved. The working mode of the catalyst is changed from the traditional long-time and continuous work to the rotation and transient work, so that the catalyst fatigue or deactivation caused by the continuous accumulation of "electrocatalytic stress" is avoided, and the stability of the catalyst is improved.

[0088] It should be noted that, without using ionomer, the present application designs a flowing and renewable catalyst use mode. The catalyst material is not fixed on the surface of the gas diffusion layer (GDL) or the separator, but flows with the electrolyte, which can increase the diffusion rate of the reactive active species to the catalyst surface, avoid the blocking of the reaction sites by the ionomer, reduce the "electrocatalytic stress" suffered by the catalyst, enhance the stability of the catalyst, and thus solve the performance degradation problem caused by the catalyst falling off or deactivation in the long-term continuous work process of the water electrolysis device such as anion exchange membrane water electrolysis (AEMWE). Moreover, the flowing catalyst of the present application is easy to recycle and reuse, further reducing the manufacturing cost of the membrane electrode.

[0089] In particular, the electrolyte delivery device is used to circulate the electrolyte containing the anode catalyst between the anode flow channel 4 and the storage device 5, and the electrolysis process is carried out under the condition of fast circulation of the electrolyte and large output current density (≥1 Acm -2 ) to improve the polarization performance and stability of the hydrogen production electrolysis cell and reduce the performance decay rate.

[0090] In an embodiment of the above-mentioned method for producing hydrogen by electrolysis of water, the hydrogen production electrolysis cell further comprises a cathode flow channel, and the cathode 2 comprises a second gas diffusion layer arranged on the cathode side of the separator 3.

[0091] The second gas diffusion layer is provided with a cathode catalyst layer, and the cathode flow channel is connected to or not connected to the electrolyte.

[0092] The second gas diffusion layer is not provided with a cathode catalyst layer, and the cathode flow channel is connected to the electrolyte containing the cathode catalyst.

[0093] It should be noted that in the above-mentioned method for producing hydrogen by electrolysis of water, the embodiment in which the cathode flow channel is not connected to the electrolyte is an anode single-side liquid connection. The first gas diffusion layer is not provided with an anode catalyst layer, and the electrolyte containing the anode catalyst is circulated in the anode flow channel and the storage device. The second gas diffusion layer is not provided with a cathode catalyst layer, and the cathode flow channel is connected to the electrolyte containing the cathode catalyst. The embodiment in which the cathode flow channel is connected to the electrolyte containing the cathode catalyst is a cathode and anode catalyst flow catalysis.

[0094] In another embodiment of the above-mentioned method for producing hydrogen by electrolysis of water, the anode catalyst and the cathode catalyst are each independently selected from one or more of a metal, a metal alloy, a metal oxide, a metal hydroxide, a metal carbide, a metal nitride, a metal sulfide, and a metal phosphide, wherein the metal in the anode catalyst and the cathode catalyst is each independently selected from one or more of Fe, Cu, Co, Ni, Zn, Mo, Mn, Re, Ru, Rh, Os, Ir, Pt, Pd, Au, and Ag.

[0095] The anode catalyst is preferably selected from one or more of IrO2, Ni3Fe, NiFe2O4, and NiFe-LDH.

[0096] The electrolyte is a solution selected from one or more of KOH, NaOH, NaHCO3, KHCO3, H2SO4, HCl, and HClO4, or pure water. The concentration of the electrolyte is 0-10 mol / L, and the temperature of the electrolyte is 0-120℃.

[0097] It should be noted that when the storage device is a common storage bottle in the art such as a blue cap reagent bottle (referred to as a blue cap bottle) and when the catalyst does not have magnetism, magnetic stirring can be applied to improve the dispersibility of the anode catalyst in the electrolyte. The method for electrolyzing water to produce hydrogen according to the present application is not limited to the above-mentioned several anode catalysts, and many anode catalysts can be applicable to the method for electrolyzing water to produce hydrogen according to the present application. The concentration of the electrolyte can be 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, etc. The temperature of the electrolyte can be 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, etc.

[0098] The dispersed concentration of the anode catalyst in the electrode liquid can be 5-200 mg / L -1 , specifically 10 mg / L -1 , 20 mg / L -1 , 30 mg / L -1 , 40 mg / L -1 , 50 mg / L -1 , 60 mg / L -1 , 70 mg / L -1 , 80 mg / L -1 , 90 mg / L -1 , 100 mg / L -1 , 110 mg / L -1 , 120 mg / L -1 , 130 mg / L -1 , 140 mg / L -1 , 150 mg / L -1 , 160 mg / L -1 , 170 mg / L -1 , 180 mg / L -1 , 190 mg / L -1 , 200 mg / L -1 , etc.

[0099] The flow rate of the peristaltic pump can be 1-150 rpm, specifically 1 rpm, 5 rpm, 10 rpm, 20 rpm, 30 rpm, 40 rpm, 50 rpm, 60 rpm, 70 rpm, 80 rpm, 90 rpm, 100 rpm, 110 rpm, 120 rpm, 130 rpm, etc.

[0100] The size of the first gas diffusion layer on the anode side and the second gas diffusion layer on the cathode side can each independently be 0.5 cm x 0.5 cm, 1 cm x 1 cm, 1 cm x 2 cm, 2 cm x 2 cm, 2 cm x 3 cm, 3 cm x 3 cm, 3 cm x 4 cm, 4 cm x 4 cm, 4 cm x 5 cm, 5 cm x 5 cm, etc., and the area can each independently be 0.25 cm 2 ~ 25 cm 2 , and the area can each independently be 1 cm 2 , 2 cm 2 , 3 cm 2 , 4 cm 2 , 5 cm 2 , 6 cm 2 , 7 cm 2 , 8 cm 2 , 9 cm 2 , 10 cm 2 , 11 cm 2 , 12 cm 2 , 13 cm 2 , 14 cm 2 , 15 cm 2 , 16 cm 2 , 17 cm 2 , 18 cm 2 , 19 cm 2 , 20 cm 2 , 21 cm 2 , 22 cm 2 , 23 cm 2 , 25 cm 2 , etc.

[0101] By controlling the dispersion concentration of the anode catalyst in the electrode solution, the flow rate of the electrolyte delivery device 6 (the flow rate of the electrolyte in which the anode catalyst is dispersed), and the area of the gas diffusion layer as described above, excellent polarization performance and stability can be obtained.

[0102] It should be noted that the above-mentioned method for electrolyzing water to produce hydrogen can be used in anion exchange membrane water electrolysis (AEMWE), alkaline water electrolysis (ALK), proton exchange membrane water electrolysis (PEMWE), nitrate reduction and other liquid phase electrocatalysis, and liquid flow batteries, and has a wider range of technical applications.

[0103] The present application will be further described in detail by the following examples, but the present application is not limited thereto. In the following examples, the experimental instruments and raw materials referred to are commercially available products, unless otherwise specified.

[0104] Reagent source description:

[0105] Commercial PtRu / C catalyst was purchased from Suzhou Shengernuo Technology Co., Ltd., with the brand Hispec9100;

[0106] Commercial IrO2 catalyst was purchased from Suzhou Shengernuo Technology Co., Ltd., with the brand SIr85;

[0107] Ionomer was purchased from Jiamu Technology (Xiamen) Co., Ltd., with the brand PFTA-80;

[0108] Anion exchange membrane was purchased from Jiamu Technology (Xiamen) Co., Ltd., with the brand KMem AM01-50;

[0109] Foamed nickel was purchased from Suzhou Shengernuo Technology Co., Ltd., with the thickness of 1 mm;

[0110] The polar plate was made of nickel plate processed by Xiamen Caoyu Precision Machinery Co., Ltd.;

[0111] Heating and temperature control were purchased from Fujian Shunchang Hongrun Precision Instrument Co., Ltd., with the model E320;

[0112] Peristaltic pump was purchased from Nuova Elettronica, with the model OEM DG2;

[0113] Commercial nano-NiFe2O4 catalyst was purchased from Shanghai Aladdin Bio-Chem Technology Co., Ltd., with the brand I113974-100g.

[0114] In the following examples:

[0115] The electrolyte inlet of the peristaltic pump communicated with the electrolyte outlet of the male bottle or the blue cap bottle, the electrolyte outlet of the peristaltic pump communicated with the electrolyte inlet of the anode flow channel, and the electrolyte outlet of the anode flow channel communicated with the electrolyte inlet of the male bottle or the blue cap bottle. The electrolyte inlet and the electrolyte outlet of the anode flow channel were located at the lower end and the upper end of the anode flow channel, respectively.

[0116] The electrolyte inlet and the electrolyte outlet of the male bottle were located at the upper end and the lower end of the male bottle, respectively. As shown in Figure 3 , the male bottle was provided with a male bottle body 14, a bottle cap, and a foot stand 16; the bottle cap was connected to the top opening of the male bottle body 14 by a fixing screw 13, the bottle cap was provided with a gas outlet 11 and a liquid inlet 12; the bottom of the bottle body 14 was hemispherical, and the lowest part of the bottom of the bottle body 14 was provided with a liquid outlet 15; the foot stand 16 was connected to the lower part of the bottle body 14.

[0117] The blue cap bottle was as shown in Figure 4The bottle mouth is placed upward, the blue cap bottle is provided with a liquid inlet pipe and a liquid outlet pipe, the bottom ends of the liquid inlet pipe and the liquid outlet pipe are located inside the blue cap bottle, the bottom end of the liquid inlet pipe is close to the bottle mouth of the blue cap bottle, the bottom end of the liquid outlet pipe is close to the inner bottom wall of the blue cap bottle, and the top ends of the liquid inlet pipe and the liquid outlet pipe are both outside the bottle mouth of the blue cap bottle.

[0118] Examples 1-3

[0119] <Assembly of electrolytic cell>

[0120] Commercially available IrO2 was selected as the anode catalyst, and foamed nickel was pressed to a thickness of 0.2 mm for use as a gas diffusion layer (2 cm x 2 cm). KMem AM01-50 was used as the anion exchange membrane, and a 0.2 mm thick foamed nickel (gas diffusion layer) sprayed with a 25 wt% content (25 wt% means that the ionomer accounts for 25% of the total mass of the PtRu / C catalyst and the ionomer) of ionomer (PFTA-80) was used as the cathode, wherein the PtRu / C catalyst loading was 1 mg cm -2 -2. The foamed nickel (gas diffusion layer) without catalyst spraying (pressed after the gas diffusion layer) was used as the anode to assemble a membrane electrode. The foamed nickel (gas diffusion layer) sprayed with the PtRu / C catalyst as the cathode was located on the cathode side of the anion exchange membrane, and the foamed nickel (gas diffusion layer) without catalyst spraying as the anode was located on the anode side of the anion exchange membrane. Snake-shaped flow channels were engraved on both the anode and cathode plates, and the plates and flow channels were connected to the blue cap bottle as the liquid storage device and the peristaltic pump as the liquid delivery device through hoses.

[0121] <Testing of electrolytic cell>

[0122] Before testing, the membrane electrode device was circulated with 300 mL of 1M KOH solution (80°C) for 2h to perform ion replacement, and the anion exchange membrane was converted from Br - form to OH - form. After the replacement was completed, a certain amount of IrO2 catalyst was added to 1L of 1M KOH at concentrations of 10 mg L -1 , 50 mg L -1 , and 100 mg L -1 , and ultrasonic treatment was performed for 30 min to make it uniformly dispersed. The dispersed catalyst alkali solution was directly used as the electrolyte and placed in the blue cap bottle, only the anode was supplied with the electrolyte, the dispersed catalyst electrolyte was sent to the anode flow channel by the peristaltic pump, and the dispersed catalyst electrolyte was circulated in the anode flow channel and the blue cap bottle, and the electrolytic cell device shown in Figure 2 was used for testing (some components such as part of the pipeline were omitted in Figure 2 ), the flow rate of the peristaltic pump was set to 20 rpm, and the stirring speed in the blue cap bottle was 600 rpm.

[0123] Comparative Example 1 (IrO2-Nafion)

[0124] The electrolytic cell was assembled according to the method in Examples 1 to 3, except that:

[0125] IrO2 catalyst was sprayed onto nickel foam using Nafion as ionomer for use as the anode. The ionomer content was 20 wt% and the catalyst loading was approximately 1 mg cm -2 The cathode was also sprayed with PtRu / C catalyst and assembled into a membrane electrode. The electrolyte was 1M KOH, and the electrolyte was only introduced into the anode side. Under the same operating conditions, the performance was compared with that of the flowing catalyst.

[0126] Comparative Example 2 (Ni foam)

[0127] The electrolytic cell was assembled according to the method in Examples 1 to 3, except that:

[0128] There is only nickel foam on the anode side without a catalyst layer, the electrolyte is 1M KOH (no dispersed catalyst in the electrolyte), and the electrolyte is only introduced into the anode side. Under the same operating conditions, the performance is compared with that of the flowing catalyst.

[0129] Test Example 1

[0130] The battery test system of Blue Power CT6002A was used to test the battery of Example 1 (10 mg L -1 ), Example 2 (50 mg L -1 ), Example 3 (100 mg L -1 ), the polarization performance and stability performance tests of the electrolytic cells of comparative example 1 (IrO2-Nafion) and comparative example 2 (Ni foam) were carried out. The stability performance test was carried out at a constant current density of 1A cm -2 The polarization curve and stability curve are measured under Figure 5 、 Figure 6 shown.

[0131] Depend on Figure 5 It can be seen that the membrane electrode of the IrO2 flowing catalyst in the three embodiments has a larger current at the same voltage (requires a smaller voltage at the same current) compared with the pure foam nickel in Comparative Example 2 (Ni foam). Therefore, the three embodiments have better polarization performance, and as the dispersion concentration of the IrO2 catalyst in the alkali solution increases, the polarization performance gradually improves.

[0132] Depend on Figure 6It can be seen that at the same current, the voltages of the three embodiments are all lower than that of Comparative Example 2 (Ni foam). Therefore, compared with Comparative Example 2 (Ni foam), the three embodiments have better stability. Moreover, in the three embodiments, as the concentration of IrO2 catalyst dispersed in the alkali solution increases, the voltage at the same current gradually decreases, and the stability of the membrane electrode gradually improves. When the catalyst concentration in the alkali solution increases to 100 mg L -1 When the working voltage is lower than that of the membrane electrode prepared by spraying method in the comparative example 1 (IrO2-Nafion) anode after 13h operation, it indicates that the working voltage of the membrane electrode prepared by spraying method in the comparative example 1 (100mg L -1 ) stability is better than that of comparative example 1, and the performance decay rate ((final voltage-initial voltage) ÷ time) of the embodiment is lower, and the final stable voltage of embodiment 3 is 1.82V.

[0133] Example 4

[0134] The electrolytic cell was assembled and tested according to the method of Example 2, except that:

[0135] The blue-capped bottle was replaced with a Malvern flask, which does not require magnetic stirring. The concentration of the catalyst in the alkali solution in this embodiment is 50 mg L -1 .

[0136] Test Example 2

[0137] The electrolytic cells of Example 2 (blue-capped bottle) and Example 4 (Marsh flask) were tested according to the method of Test Example 1. The polarization performance of the membrane electrode was tested at 80°C, and the polarization curves were as follows: Figure 7 shown.

[0138] Depend on Figure 7 It can be seen that at the same voltage of 1.8V, the membrane electrode of Example 4 using the Malchnitz flask can output 1.1Acm -2 The current density of the membrane electrode output in Example 2 is 0.8Acm -2 The membrane electrode performance of Example 4 using the Malchnitz flask is better than that of Example 2 using the blue-capped flask, so the effect of using the Malchnitz flask is better than that of the blue-capped flask.

[0139] Examples 5 to 7

[0140] The electrolytic cell was assembled and tested according to the method in Example 4, except that:

[0141] Commercially available nano-NiFe2O4 was selected as the anode catalyst, and 10 mg L -1 , 50mg L -1 、100mg L -1 The catalyst is dispersed in the electrolyte at a concentration of , and other conditions are the same as in Example 4.

[0142] Comparative Example 3 (NiFe2O4-Nafion)

[0143] The electrolytic cell was assembled according to the method of Comparative Example 1, except that:

[0144] Commercially available nano-NiFe2O4 was used as the anode catalyst, and the operating temperature was 60°C.

[0145] Test Example 3

[0146] According to the method of Test Example 1, the samples of Examples 5 to 7 (10 mg L -1 , 50mg L -1 、100mg L -1 ), Comparative Example 2 (Nifoam), Comparative Example 3 (NiFe2O4-Nafion) electrolytic cells were tested, and the polarization performance and stability of the membrane electrode were tested at 60°C. The stability was 1A cm -2 The test was carried out at a current density of , and the polarization curve and stability curve were Figure 8 、 Figure 9 .

[0147] Depend on Figure 8 It can be seen that 10 mg L dispersed in alkali solution -1 The membrane electrode with NiFe2O4 catalyst has significantly improved polarization performance compared with the pure foam nickel in Comparative Example 2 (Nifoam) and Comparative Example 3 (NiFe2O4-Nafion). In addition, in the three embodiments, as the dispersion concentration of NiFe2O4 catalyst in the alkali solution increases, the polarization performance gradually improves. The polarization performance of the three embodiments is significantly better than that of the pure foam nickel in Comparative Example 2 (Ni foam) and the membrane electrode sprayed with ionomer in Comparative Example 3 (NiFe2O4-Nafion).

[0148] Depend on Figure 9 It can be seen that Example 5 (10 mg L -1 ) The final stable voltage dropped from 2.12V in Comparative Example 2 (Ni foam) to 2V, and the stability was significantly improved and the performance attenuation rate was reduced. -1 Increased to 50mg L -1 , the performance of the membrane electrode is further improved. However, as the catalyst dispersion concentration increases to 100 mg L -1 , the polarization performance has hardly improved, and the final stable voltage is almost the same, all around 1.99 V. This indicates that the catalyst content has reached a maximum saturation value, which may be related to the limited space of the membrane electrode assembly flow channel.

[0149] Examples 8 to 10

[0150] The electrolyzer was assembled and tested according to the method in Example 4, except that:

[0151] The anode catalyst was replaced by nano-NiFe-LDH catalyst, and the concentration of the nano-NiFe-LDH catalyst dispersed in 1M KOH was 20mg / L -1 , 40mg / L -1 , and 80mg / L -1 , respectively. The preparation process of the nano-NiFe-LDH catalyst was as follows:

[0152] 427mg of nickel chloride and 243mg of ferric chloride were dissolved in a mixed solution of 670μL of deionized water and 1mL of ethanol, 92μL of acetylacetone was then added, and the mixture was stirred for 30min. 915μL of propylene oxide was then added, and the mixture was stirred for 1min. The mixture was left to react at room temperature for 30h, and was then directly dried to obtain a NiFe-LDH powder.

[0153] Comparative Example 4 (NiFe LDH-Nafion)

[0154] The electrolyzer was assembled and tested according to the method in Comparative Example 1, except that:

[0155] The nano-NiFe-LDH catalyst prepared above was fixed on the anode side of the nickel foam as an anode catalyst layer using Nafion as an ionomer.

[0156] Test Example 4

[0157] The electrolyzers of Examples 8-10, Comparative Example 2 (Ni foam), and Comparative Example 4 (NiFe LDH-Nafion) were tested according to the method in Test Example 1, and the polarization curves and stability curves obtained are shown in Figure 10 and Figure 11 .

[0158] As shown in Figure 10 , the membrane electrode performance of the 20mg / L -1 NiFe-LDH catalyst dispersed in the alkaline solution was significantly improved in terms of polarization performance relative to Comparative Example 2 (Ni foam) pure nickel foam and Comparative Example 4 (NiFe LDH-Nafion), especially at high current densities. In the three examples, the polarization performance gradually improved as the concentration of the NiFe-LDH catalyst dispersed in the alkaline solution increased, and the polarization performance of the three examples was significantly better than that of Comparative Example 2 (Ni foam) pure nickel foam and Comparative Example 4 (NiFe LDH-Nafion) using ionomer spraying.

[0159] As shown in Figure 11It can be seen that the initial voltages of Examples 8-10 are 1.65 V, 1.64 V and 1.63 V, respectively, which are close to the initial voltage 1.65 V of Comparative Example 4 (NiFe LDH-Nafion), but the voltages of Examples 8-10 are 1.66 V, 1.66 V and 1.65 V, respectively, after 24 h, while the voltage of Comparative Example 4 (NiFe LDH-Nafion) rises to 1.76 V, and the performance decay rate is significantly higher than that of Examples 8-10. This shows that the stability of the NiFe-LDH flow catalyst membrane electrode is much better than that of the fixed NiFe-LDH catalyst membrane electrode.

[0160] The above examples show that the membrane electrode prepared by the flow catalyst water electrolysis hydrogen production technology of the present application can achieve similar or even better performance than the ionomer spraying method, and has better stability. As can be seen from the polarization curve, at the same voltage, the output current can continuously increase with the increase of the amount of catalyst dispersed in the alkali solution, but due to the limitation of the flow channel space and the effective area of the catalyst layer, there is a maximum catalyst dosage.

[0161] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "back", "left", "right" and the like indicate the orientation or positional relationship based on the working state of the present application, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0162] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0163] The above describes the present application in combination with the preferred embodiments, but these embodiments are only exemplary and serve only to illustrate. On this basis, various substitutions and improvements can be made to the present application, and these all fall within the protection scope of the present application.

Claims

1. A water electrolysis hydrogen production electrolyzer, characterized in that It features: Anode (1), cathode (2), diaphragm (3), Anode flow channel (4), a storage device (5) for storing an electrolyte in which an anode catalyst is dispersed, and Electrolyte delivery device (6); wherein the electrolyte inlet of the electrolyte transport device (6) is connected to the electrolyte outlet of the storage device (5), the electrolyte outlet of the electrolyte transport device (6) is connected to the electrolyte inlet of the anode flow channel (4), and the electrolyte outlet of the anode flow channel (4) is connected to the electrolyte inlet of the storage device (5); The storage device (5) is a Malvern flask; The Malvern flask is provided with a Malvern flask body (14), a bottle cap and a tripod (16); the bottle cap is connected to the top opening of the Malvern flask body (14) by a fixing screw (13), and the bottle cap is provided with an air outlet (11) and a liquid inlet (12); the bottom of the Malvern flask body (14) is hemispherical, and a liquid outlet (15) is provided at the lowest point of the bottom of the Malvern flask body (14); the tripod (16) is connected to the lower part of the Malvern flask body (14).

2. The electrolytic cell for producing hydrogen from water by electrolysis according to claim 1, wherein: The anode (1) comprises a first gas diffusion layer, the first gas diffusion layer is arranged on the anode side of the diaphragm (3), and no anode catalyst layer is arranged on the first gas diffusion layer; The cathode (2) comprises a second gas diffusion layer, which is arranged on the cathode side of the diaphragm (3).

3. The electrolytic cell for producing hydrogen by electrolysis of water according to claim 2, wherein: The electrolytic water hydrogen production electrolyzer is also provided with: cathode flow channel, a cathode storage device for storing electrolyte, and a catholyte delivery device; The electrolyte inlet of the cathode electrolyte transport device is connected to the electrolyte outlet of the cathode storage device, the electrolyte outlet of the cathode electrolyte transport device is connected to the electrolyte inlet of the cathode flow channel, and the electrolyte outlet of the cathode flow channel is connected to the electrolyte inlet of the cathode storage device.

4. The electrolytic cell for producing hydrogen from water by electrolysis according to claim 3, wherein: The cathode storage device is used to store an electrolyte in which a cathode catalyst is dispersed.

5. The electrolytic cell for producing hydrogen by electrolysis of water according to claim 1, wherein: The electrolyte delivery device (6) is selected from a peristaltic pump, a reciprocating pump or a centrifugal pump.

6. The electrolytic cell for producing hydrogen by electrolysis of water according to claim 5, characterized in that: The reciprocating pump is selected from a diaphragm pump.

7. The electrolytic cell for producing hydrogen by electrolysis of water according to claim 1, characterized in that: The electrolyte inlet and electrolyte outlet of the anode flow channel (4) are respectively arranged at the lower end and the upper end thereof.

8. The electrolytic cell for producing hydrogen by electrolysis of water according to claim 1, characterized in that: The diaphragm (3) is selected from an anion exchange membrane, a proton exchange membrane, an ion solvent membrane or an alkaline water electrolysis membrane.

9. A method for producing hydrogen by electrolysis of water, characterized in that: The method is carried out in an electrolytic cell for producing hydrogen from electrolyzed water according to any one of claims 1 to 8, wherein the electrolytic cell for producing hydrogen from electrolyzed water is provided with: Anode (1), cathode (2), diaphragm (3), Anode flow channel (4), a storage device (5) for storing an electrolyte in which an anode catalyst is dispersed, and Electrolyte delivery device (6); The method includes: The electrolyte transport device (6) allows the electrolyte containing the anode catalyst to circulate in the anode flow channel (4) and the storage device (5).

10. The method according to claim 9, characterized in that The electrolytic cell for producing hydrogen by electrolysis of water is further provided with a cathode flow channel, the cathode (2) comprises a second gas diffusion layer, and the second gas diffusion layer is provided on the cathode side of the diaphragm (3); A cathode catalyst layer is provided on the second gas diffusion layer, and an electrolyte may or may not be passed into the cathode flow channel.

11. The method according to claim 9, characterized in that The electrolytic cell for producing hydrogen by electrolysis of water is further provided with a cathode flow channel, the cathode (2) comprises a second gas diffusion layer, and the second gas diffusion layer is provided on the cathode side of the diaphragm (3); No cathode catalyst layer is provided on the second gas diffusion layer, and the cathode flow channel is fed with an electrode liquid in which cathode catalyst is dispersed.

12. The method according to claim 11, characterized in that The anode catalyst and cathode catalyst are each independently selected from one or more of metals, metal alloys, metal oxides, metal hydroxides, metal carbides, metal nitrides, metal sulfides, and metal phosphides; The electrolyte is a solution selected from one or more of KOH, NaOH, NaHCO3, KHCO3, H2SO4, HCl, and HClO4, or pure water.

13. The method according to claim 12, characterized in that The metals in the anode catalyst and the cathode catalyst are independently selected from one or more of Fe, Cu, Co, Ni, Zn, Mo, Mn, Re, Ru, Rh, Os, Ir, Pt, Pd, Au, and Ag.

14. The method according to claim 12, characterized in that The anode catalyst is selected from one or more of IrO2, Ni3Fe, NiFe2O4, and NiFe-LDH.

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