Conductive diamond-based anion exchange membrane water electrolysis electrode, preparation method thereof and water electrolysis hydrogen production tank comprising electrode

Abstract

The invention provides an anion exchange membrane water electrolysis hydrogen production tank which comprises a cathode and an anode, and the anode is a conductive diamond-based anion exchange membrane water electrolysis electrode. A catalyst of the conductive diamond-based anion exchange membrane water electrolysis electrode is conductive diamond composite transition metal or transition metal alloy. According to the supported catalyst obtained by the preparation method disclosed by the invention, the survival rate of active sites of the metal oxide catalyst of the anode non-noble metal can be remarkably improved, and the service life of the catalyst is prolonged; compared with a traditional catalyst layer formed by a metal oxide, the supported catalyst obtained by the preparation method disclosed by the invention has the advantages that the electronic conductivity of the catalyst can be remarkably improved, and meanwhile, the structured catalyst is beneficial to the operation of an electrolytic bath under high current density. And the catalyst-electrode integrated rapid thermal forming method is beneficial to large-scale mass production application.

Description

Technical Field

[0001] The present invention relates to the field of materials for hydrogen production by electrolyzing water, and particularly to catalyst materials for electrolytic hydrogen production in an alkaline environment. Background Art

[0002] Green hydrogen, that is, a mode of producing hydrogen without carbon emissions, has been listed as an important development route for establishing an environmentally friendly energy society in the 21st century by many countries. The currently most popular proton exchange membrane electrolysis technology has become one of the perfect technologies for promoting large-scale renewable energy electrolytic water hydrogen production due to its high power density and excellent start-stop ability. However, the high cost of noble metal materials in proton exchange membrane electrolyzers restricts their large-scale application. At the same time, problems such as low efficiency and hydrogen-oxygen permeation in alkaline water electrolysis technology also pose environmental protection requirements. Moreover, its poor coupling with highly volatile renewable energy makes it difficult to continue developing. The anion exchange membrane electrolysis technology that has gradually received attention in recent years is an effective evolution of alkaline water electrolysis. It can avoid the use of noble metals restricted by resources and has the high response characteristics of proton exchange membrane electrolysis technology, making it the most influential electrolytic water technology. Currently, the anode material of anion exchange membrane electrolysis technology is mainly transition metal oxide catalysts. Although they have high electrocatalytic activity for water oxidation and oxygen evolution at the anode, they have low conductivity and the actual problem of sintering of active centers. One of the solutions is to support them on a conductive carrier that can work for a long time in a harsh high-potential environment and is resistant to electrochemical corrosion to form a structured catalyst, which can effectively reduce the problems of active site sintering and low conductivity, provide an electrolyzer with a longer lifespan and higher efficiency, and thus promote the faster large-scale application of anion exchange membrane electrolysis technology. Summary of the Invention

[0003] Based on the problems mentioned above, it is necessary to provide a preparation method for a conductive diamond-based anion exchange membrane electrolytic water electrode and an anion exchange membrane electrolytic water hydrogen production cell using the conductive diamond-based anion exchange membrane electrolytic water electrode. Conductive diamond, as a corrosion-resistant electrode material, is very suitable for use as the support of the anode catalyst. Using such a carrier technology can effectively disperse the catalyst on it and provide the conductivity of the catalyst layer, effectively solving the above problems.

[0004] The present invention provides an anion exchange membrane electrolytic water hydrogen production cell, including a cathode and an anode, and the anode uses a conductive diamond-based anion exchange membrane electrolytic water electrode.

[0005] In one embodiment, the catalyst of the conductive diamond-based anion exchange membrane electrolytic water electrode is a conductive diamond composite transition metal or a transition metal alloy.

[0006] In one embodiment, the transition metal includes one or more of iron, cobalt, nickel, titanium, manganese, copper, and molybdenum.

[0007] In one embodiment, the particle size of the conductive diamond is 20 nm-1 μm.

[0008] In one embodiment, the conductive diamond-based anion exchange membrane water electrolysis electrode is an electrode integrating nickel felt and the catalyst.

[0009] The method for preparing a conductive diamond-based anion exchange membrane water electrolysis electrode comprises the following steps:

[0010] S1: providing conductive diamond particles;

[0011] S2: Adding conductive diamond and resin ethanol solution to the nitric acid solution containing transition metal salt, fully dispersing to obtain electrode slurry;

[0012] S3: impregnating the nickel felt in the electrode slurry to obtain a nickel felt with the surface impregnated with the electrode slurry;

[0013] S4: oxidatively decomposing the resin to obtain a conductive diamond-based anion exchange membrane water electrolysis electrode.

[0014] In one embodiment, the solid content of the resin and the conductive diamond in the electrode slurry is 1:1, and the solid content of the metal is 50%.

[0015] In one embodiment, S3 comprises: immersing the nickel felt in the electrode slurry, and immersing the nickel felt in a nitrogen environment of 4 MPa at 50° C. for 72 hours to obtain the nickel felt with the electrode slurry impregnated on the surface.

[0016] In one embodiment, S4 includes: treating the nickel felt with the electrode slurry impregnated on the surface in an air atmosphere at 450-600°C for 2 hours to oxidatively decompose the resin, and cooling in air when the temperature drops to 400-450°C to obtain a conductive diamond-based anion exchange membrane water electrolysis electrode.

[0017] The conductive diamond-based anion exchange membrane water electrolysis electrode is prepared by any one of the above-mentioned methods for preparing the conductive diamond-based anion exchange membrane water electrolysis electrode.

[0018] An anion exchange membrane water electrolysis hydrogen production cell uses the conductive diamond-based anion exchange membrane water electrolysis electrode as claimed in any one of the above claims.

[0019] The beneficial effects of the present invention are:

[0020] 1. The supported catalyst obtained by the preparation method of the present application can significantly improve the survival rate of the active sites of the metal oxide catalyst of the anode non-precious metal and increase the service life of the catalyst;

[0021] 2. Compared with the traditional catalyst layer formed by metal oxides, the supported catalyst obtained by the preparation method of the present application can significantly improve the electronic conductivity of the catalyst. At the same time, the structured catalyst is beneficial to the operation of the electrolytic cell at high current densities.

[0022] 3. The rapid thermoforming method of catalyst-electrode integration is conducive to large-scale mass production applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0024] Figure 1 It is a flowchart of a preparation method of a conductive diamond-based anion exchange membrane electrolysis water electrode according to an embodiment of the present invention.

[0025] Figure 2 It is an electron microscope image of conductive diamond according to an embodiment of the present invention.

[0026] Figure 3 It is an electron microscope image of the electrode paste according to an embodiment of the present invention.

[0027] Figure 4 It is a Raman spectrum diagram of conductive diamond according to an embodiment of the present invention.

[0028] Figure 5 It is a comparison diagram of polarization curves between the embodiment and the comparative example of the present invention.

[0029] Figure 6 It is a diagram of the test results of constant current durability comparison between the embodiment and the comparative example of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0031] The present invention provides a preparation method of a conductive diamond-based anion exchange membrane electrolysis water electrode, as Figure 1 shown, including the following steps:

[0032] Step S1: Provide conductive diamond particles.

[0033] The diamond / conductive diamond particles can be obtained from the market or prepared by oneself, for example, by explosion method.

[0034] Non-conductive diamond particles are obtained, for example, conductive diamond is obtained by chemical vapor deposition. For example, in one embodiment, step S0 is also included, wherein the step S0: conductive diamond particles are obtained by hot wire chemical vapor deposition. Specifically, the parameters of the hot wire chemical vapor deposition method are: base temperature 500-800°C, hot wire temperature 180-2400°C, gas pressure 1-5kPa, hydrogen 100-1000sccm, methane 1-20sccm, borane 1-20sccm, and growth for more than 10 minutes. For example, in another embodiment, step S0: conductive diamond particles are obtained by microwave plasma chemical vapor deposition. Specifically, the parameters of the microwave plasma chemical vapor deposition method are: microwave power 500-3000 watts, hydrogen 100-1000 sccm, methane 1-20 sccm, borane 1-10 sccm, base temperature 500-700°C, gas pressure 4-6 kPa, and growth time 3-10 hours.

[0035] The conductive diamond can also be prepared by other methods, for example, by using a high temperature and high pressure method, under high temperature and high pressure (above 500°C, exceeding 10GPa), the catalyst / graphite / boron source is used to obtain conductive diamond particles through an oil hydraulic machine, and then the conductive diamond particles are broken up by physical means.

[0036] In one embodiment, the particle size of the conductive diamond is 20 nm-1 μm.

[0037] Step S2: Add conductive diamond and resin in ethanol solution to the nitric acid solution containing transition metal salt, and fully disperse them to obtain electrode slurry.

[0038] Among them, the transition metal is a catalyst active material. In one embodiment, the transition metal includes one or more of iron, cobalt, nickel, titanium, manganese, copper, and molybdenum. Specifically, it is composed of one or more nanometals or metal oxides of iron, cobalt, nickel, titanium, manganese, copper, and molybdenum.

[0039] For example, in this step, nano metal oxide is used. In one embodiment, different commercially available pure metal nanoparticles are used, mixed solid phase oxidized and then pickled to obtain the nano metal oxide. Specifically, one or more of iron, cobalt, nickel, titanium, manganese, copper and molybdenum with a size range of 2nm-20nm are selected, mixed thoroughly, oxidized and sintered in an air atmosphere at 180-600°C, and then pickled at 90°C for 10-20min using 0.1-1M non-oxidizing acid such as hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, etc., to obtain the nano metal oxide required by the present invention.

[0040] In another embodiment, one or more metal salts corresponding to iron, cobalt, nickel, titanium, manganese, copper, molybdenum, etc. (such as manganese chloride, iron sulfate, nickel acetylacetonate, etc.) are reduced using common reducing agents such as NaBH4, hydrazine hydrate, etc., and then further oxidized and sintered at 180 - 600 °C to obtain the nano-metal oxides required by the present invention.

[0041] In yet another embodiment, one or more metal oxides of iron, cobalt, nickel, titanium, manganese, copper, molybdenum, etc. at the micron level are mixed and subjected to high-energy ball milling, and then further oxidized and sintered to obtain the nano-metal oxides required by the present invention.

[0042] In one embodiment, for the electrode paste obtained in this step, the solid content ratio of the resin to the conductive diamond is 1:1, and the metal solid content is 50%.

[0043] Step S3: Immerse the nickel felt in the electrode paste to obtain a nickel felt with the electrode paste impregnated on its surface.

[0044] Among them, the nickel felt serves as the anode of the electrolytic water electrode of the conductive diamond-based anion exchange membrane. In one embodiment, step S3 includes: immersing the nickel felt in the above electrode paste, and performing impregnation treatment in a nitrogen environment at 50 °C and 4 MPa for 72 h to obtain a nickel felt with the electrode paste impregnated on its surface.

[0045] Step S4: Oxidatively decompose the resin to obtain the electrolytic water electrode of the conductive diamond-based anion exchange membrane.

[0046] In one embodiment, in order to oxidatively decompose the resin, step S4 includes: treating the nickel felt impregnated with the electrode paste in an air atmosphere at 450 - 600 °C for 2 h to oxidatively decompose the resin, and cooling in air when the temperature drops to 400 - 450 °C to obtain the electrolytic water electrode of the conductive diamond-based anion exchange membrane.

[0047] The present invention provides an electrolytic water electrode of a conductive diamond-based anion exchange membrane, which is prepared by the preparation method of the electrolytic water electrode of the conductive diamond-based anion exchange membrane described in any one of the above.

[0048] The present invention also provides an anion exchange membrane electrolytic water hydrogen production tank, which includes a cathode and an anode, and the anode uses the electrolytic water electrode of the conductive diamond-based anion exchange membrane described above. Specifically, the catalyst of the electrolytic water electrode of the conductive diamond-based anion exchange membrane is a conductive diamond composite transition metal or a transition metal alloy. Among them, the conductive diamond is the catalyst carrier, and the transition metal or the transition metal alloy is the active material. Among them, Figure 2 is the electron microscope image of the conductive diamond used in one embodiment of the present invention, Figure 3 is the electron microscope image of the electrode paste used in one embodiment of the present invention,Figure 4 A Raman spectrum of conductive diamond used in one embodiment of the present invention.

[0049] The conductive diamond-based anion exchange membrane water electrolysis electrode prepared by the present invention through the preparation method is an electrode integrating nickel felt and the catalyst.

[0050] The beneficial effects of the present invention are:

[0051] 1. The supported catalyst obtained by the preparation method of the present application can significantly improve the survival rate of the active sites of the metal oxide catalyst of the anode non-precious metal and increase the service life of the catalyst;

[0052] 2. Compared with the traditional catalyst layer formed by metal oxides, the supported catalyst obtained by the preparation method of the present application can significantly improve the electronic conductivity of the catalyst. At the same time, the structured catalyst is conducive to the operation of the electrolytic cell at a high current density.

[0053] 3. The rapid hot forming method of catalyst-electrode integration is conducive to large-scale mass production applications.

[0054] Hereinafter, specific embodiments of the electrode preparation method and the electrode of the present invention are provided.

[0055] Example 1

[0056] Step S1:

[0057] Conductive diamond particles are provided.

[0058] Step S2:

[0059] Conductive diamond and polyvinyl pyrrolidone solution of resin are added to nitric acid solution containing iron, cobalt and nickel transition metal salts, and fully dispersed to obtain electrode slurry.

[0060] Step S3:

[0061] A nickel felt serving as an anode was immersed in the electrode slurry to obtain a nickel felt having its surface impregnated with the electrode slurry.

[0062] Step S4:

[0063] The resin is oxidized and decomposed to obtain a conductive diamond-based anion exchange membrane water electrolysis electrode.

[0064] The electrode obtained in this embodiment has a metal loading of 3.8 mg / cm 2 , an anode electrode of an iron-cobalt-nickel ternary alloy oxide with a molar ratio of 1:2:7.

[0065] Example 2

[0066] Wherein, step S2:

[0067] Conductive diamond and polyvinyl pyrrolidone solution of resin are added to nitric acid solution containing manganese, copper and cobalt transition metal salts, and fully dispersed to obtain electrode slurry.

[0068] The rest of the contents are the same as those in Example 1.

[0069] The electrode obtained in this embodiment has a metal loading of 3.8 mg / cm 2 , an anode electrode of a manganese, copper and cobalt ternary alloy oxide with a molar ratio of 2:1:7.

[0070] Example 3

[0071] Wherein, step S2:

[0072] Conductive diamond and phenolic resin are added to a nitric acid solution containing iron, cobalt and nickel transition metal salts, and fully dispersed to obtain electrode slurry.

[0073] The electrode obtained in this embodiment has a metal loading of 3.8 mg / cm 2 , an anode electrode of an iron-cobalt-nickel ternary alloy oxide with a molar ratio of 1:2:7.

[0074] The present invention provides a pair of ratios, using a metal loading of 10 mg / cm 2 , anode electrode of commercially available unsupported iron-nickel hydroxide catalyst.

[0075] Figure 5 This is a comparison diagram of polarization curves of Example 1, Example 2, Example 3 and the comparative example of the present invention. The cathode uniformly uses a platinum loading of 0.4 mg. Pt / cm 2 Commercially available platinum-carbon catalyst.

[0076] Figure 6 This is a graph showing the constant current durability comparison test results of Example 1, Example 2, Example 3 and the comparative example of the present invention.

[0077] Table 1 is a durability test and comparison table of Example 1, Example 2, Example 3 and Comparative Example of the present invention. 2 , a durability test of 500h constant current electrolysis was carried out, and the durability of each embodiment and the comparative example at 0.4A / cm 2 The electrolysis voltage.

[0078] Comparison of galvanostatic durability Comparative example Example 1 Example 2 Example 3 Percentage of voltage increase rate 5.6％ 0.7％ 2.0％ 3.8％

[0079] Table 1

[0080] As can be seen from Table 1, after testing, the voltage increase rates of the electrodes of Examples 1-3 of the present invention are all lower than those of the comparative example after 500 h of testing, indicating that the use of the integrated electrodes of this patent is superior to the electrodes prepared by coating with commercially available pure nickel iron hydroxide catalysts with high loadings in terms of durability.

[0081] Table 2 is a comparison table of the conductivity of Example 1, Example 2, Example 3 and the comparative example of the present invention. The four-probe resistivity tester described in the National Metrological Verification Regulation JJG 508-2004 of the People's Republic of China was used to compare the surface conductivity of the electrodes of the comparative example and each example. Among them, Examples 1-3 are Examples 1-3 described above, and the comparative example is an electrode formed by coating a commercially available catalyst on nickel felt.

[0082] Comparison of electrode conductivity Comparative example Example 1 Example 2 Example 3 Conductivity S / cm 0.6 2.1 3.2 0.8

[0083] Table 2

[0084] As can be seen from Table 2, the conductivity of the catalysts of the examples of the present invention is higher than that of the comparative example, and a higher material conductivity performance can be obtained by using the catalyst-electrode integrated design of this patent.

[0085] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0086] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. Anion exchange membrane water electrolysis hydrogen production cell, characterized in that: The invention comprises a cathode and an anode, wherein the anode uses a conductive diamond-based anion exchange membrane to electrolyze water.

2. The anion exchange membrane water electrolysis hydrogen production cell according to claim 1, characterized in that: The catalyst of the conductive diamond-based anion exchange membrane water electrolysis electrode is a conductive diamond composite transition metal or a transition metal alloy.

3. The anion exchange membrane water electrolysis hydrogen production cell according to claim 2, characterized in that: The transition metal includes one or more of iron, cobalt, nickel, titanium, manganese, copper and molybdenum.

4. The anion exchange membrane water electrolysis hydrogen production cell according to claim 2, characterized in that: The particle size of the conductive diamond is 20nm-1μm.

5. The anion exchange membrane water electrolysis hydrogen production cell according to any one of claims 1 to 4, characterized in that: The conductive diamond-based anion exchange membrane water electrolysis electrode is an electrode integrating nickel felt and the catalyst.

6. A method for preparing a conductive diamond-based anion exchange membrane water electrolysis electrode, characterized in that: The steps include: S1: providing conductive diamond particles; S2: Adding conductive diamond and resin ethanol solution to the nitric acid solution containing transition metal salt, fully dispersing to obtain electrode slurry; S3: impregnating the nickel felt in the electrode slurry to obtain a nickel felt with the surface impregnated with the electrode slurry; S4: oxidatively decomposing the resin to obtain a conductive diamond-based anion exchange membrane water electrolysis electrode.

7. The method for preparing a conductive diamond-based anion exchange membrane water electrolysis electrode according to claim 6, characterized in that: The solid content of the resin and the conductive diamond in the electrode slurry is 1:1, and the solid content of the metal is 50%.

8. The method for preparing a conductive diamond-based catalyst for producing hydrogen by anion exchange membrane water electrolysis according to claim 6, characterized in that: The step S3 comprises: immersing the nickel felt in the electrode slurry, and immersing the nickel felt in a nitrogen environment of 4 MPa at 50° C. for 72 hours to obtain the nickel felt with the electrode slurry impregnated on the surface.

9. The method for preparing a conductive diamond-based catalyst for producing hydrogen by anion exchange membrane water electrolysis according to claim 6, characterized in that: The S4 comprises: treating the nickel felt with the electrode slurry impregnated on the surface in an air atmosphere at 450-600° C. for 2 hours to oxidize and decompose the resin, and cooling in air when the temperature drops to 400-450° C. to obtain a conductive diamond-based anion exchange membrane water electrolysis electrode.

10. A conductive diamond-based anion exchange membrane water electrolysis electrode, characterized in that: The conductive diamond-based anion exchange membrane water electrolysis electrode is prepared by the preparation method of any one of claims 6 to 9.

11. Anion exchange membrane water electrolysis hydrogen production cell, characterized in that: A conductive diamond-based anion exchange membrane water electrolysis electrode is used as described in any one of claims 6 to 10.

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