A hydrogen production electrode, a preparation method therefor and an application thereof

Abstract

The application provides a hydrogen production electrode and a preparation method and application thereof, and the hydrogen production electrode comprises an electrode substrate and a catalytic layer which is compounded on the surface of the electrode substrate; and the catalytic layer is formed by a layered metal hydroxide-sulfate complex. In the hydrogen production process, the catalytic layer of the hydrogen production electrode has high specific surface area and porosity, and the density of active sites is high; and the sulfate ions in the catalytic layer have a blocking effect on the chlorine ions in the electrolysis reaction. The hydrogen production electrode provided by the application is integrally formed in the preparation process, the electrode substrate and the catalyst are firmly combined, the generation of contact resistance is avoided, and the conductivity is good. Meanwhile, the application does not use noble metal components, and the cost is low, which is conducive to large-scale promotion.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of hydrogen energy and seawater resource utilization, and particularly relates to a hydrogen production electrode and a preparation method and application thereof. BACKGROUND

[0002] Water electrolysis hydrogen production is a technical method for realizing large-scale green hydrogen production at present, and plays a crucial role in promoting hydrogen energy social construction and realizing the double carbon goal.

[0003] Seawater is very rich in reserves on the earth, and offshore wind energy, solar energy, wave energy and other resources are rich, so that seawater can be used for hydrogen production by coupling seawater electrolysis with offshore renewable energy power generation. Seawater has a high salt content, and in most offshore hydrogen production projects, seawater needs to be pretreated through reverse osmosis and other processes, which is difficult and costly. The way of directly using seawater to produce hydrogen will cause problems such as poor activity and short service life of the electrolytic hydrogen production electrode material. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a hydrogen production electrode and a preparation method and application thereof, which can reduce the negative effects of chloride ions in seawater and improve the hydrogen production activity of the hydrogen production electrode.

[0005] To achieve the above purpose, the technical scheme of the present application is a hydrogen production electrode, which comprises an electrode substrate and a catalytic layer compounded on the surface of the electrode substrate; the catalytic layer is formed by a layered metal hydroxide-sulfate complex.

[0006] In the hydrogen production electrode of the present application, the electrode substrate is a porous or dense conductive metal sheet material, preferably one or more of iron, nickel, cobalt and molybdenum. In one embodiment, the electrode substrate is selected from foamed nickel. The electrode substrate of the present application has a thickness of 100-500 μm, preferably 300-500 μm.

[0007] In the hydrogen production electrode of the present application, the catalytic layer is compounded on the surface of the electrode substrate by a layered double metal hydroxide-sulfate complex. In one embodiment, the layered double metal hydroxide-sulfate complex has the following structure:

[0008] (M1(OH) a ) x -Na + y -(M2(OH) b ) z -(SO4 2- ) y / 2 ;

[0009] wherein M1 is an electrode base metal element, preferably iron, nickel, cobalt or molybdenum, is a divalent ion, M2 is iron, nickel, cobalt or molybdenum, is a trivalent ion, and M1 and M2 are not the same; a and b are independently 2, 3, 4 or 5; x and z satisfy the following relationship: (2-a)x+(3-b)z=0; y is 2, 3, 4, 5, 6, 7, 8, 9 or 10. In one embodiment, M1 and M2 are nickel and iron, respectively. The catalytic layer of the present application has a thickness of 50-500 nm, preferably 50-200 nm. The catalytic layer of the present application can be compounded on one side of the electrode base or on both sides of the electrode base, which is not limited in the present application. The electrode base is first corroded, and metal corrosion and in-situ deposition reactions occur on the surface of the electrode base; after the electrode base subjected to surface corrosion is reacted with a metal sulfate precursor solution, it is reacted with an alkali solution under the protection of a reducing atmosphere, and a layered double hydroxide-sulfate composite is formed on the surface of the electrode base, which can act as a catalytic layer, reduce the negative effects of chloride ions in seawater, and improve the electrolytic hydrogen activity.

[0010] The hydrogen production electrode obtained by the present application comprises an electrode base and a catalytic layer compounded on the surface of the electrode base, and the catalytic layer is formed by a layered double hydroxide-sulfate composite. In the hydrogen production process, the catalytic layer has a high specific surface area and porosity, a high active site density, and the sulfate ions in the catalytic layer have a blocking effect on the chloride ions in the electrolysis reaction. Experimental results show that, when the hydrogen production electrode is used for electrolytic hydrogen production in seawater, the voltage does not change significantly after 144 h of reaction, which can effectively enhance the reaction selectivity and improve the service life of the hydrogen production electrode.

[0011] The present application also provides a preparation method of a hydrogen production electrode, comprising the following steps:

[0012] After the electrode base subjected to surface corrosion is reacted with a metal sulfate precursor solution, it is co-precipitated under alkaline conditions, and a catalytic layer is formed on the surface of the electrode base to obtain a hydrogen production electrode; the metals in the electrode base and the metals in the metal sulfate precursor are not the same.

[0013] The electrode base is first subjected to surface corrosion, and before the surface corrosion, the electrode base is preferably pretreated, and the pretreatment comprises: sequentially washing the electrode base with water, alcohol and acid, specifically: sequentially washing the electrode base with water, alcohol and 0.05-0.5 mol / L dilute hydrochloric acid for 2-3 times to obtain a pretreated electrode base. The electrode base is washed with alcohol to remove liposoluble impurities on the surface of the electrode base; and the electrode base is washed with dilute hydrochloric acid to remove oxides on the surface of the electrode base.

[0014] After the pretreatment, surface corrosion is performed. The surface corrosion according to the present application is specifically as follows: the electrode substrate is subjected to surface corrosion using a NaCl solution with a concentration of 0.5-1 mol / L, the corrosion time is 12-24 h, and the temperature is 20-60°C. The electrode substrate surface undergoes metal corrosion and in-situ deposition reaction, forming a metal hydroxide structure, and the reaction formula is as shown below:

[0015] M1 + 2e- = M1 2+

[0016] M1 + 3e- = M1 3+

[0017] M1 + 2H2O = M1(OH)2 + 2H 2+ +

[0018] M1 + 3H2O = M1(OH)3 + 3H 3+ +

[0019] wherein M1 is an electrode substrate metal element, preferably one or more of iron, nickel, cobalt and molybdenum. In one embodiment, M1 is selected from the metal nickel.

[0020] The electrode substrate according to the present application can be subjected to single-sided surface corrosion or double-sided surface corrosion, which is not limited herein. In one embodiment, the electrode substrate is immersed in a 0.5-1 mol / L NaCl solution to perform surface corrosion, thereby obtaining an electrode substrate subjected to double-sided surface corrosion. In one embodiment, the electrode substrate is placed on a support, the support is placed in a reaction container, the lower surface of the electrode substrate contacts the 0.5-1 mol / L NaCl solution, and the upper surface of the electrode substrate contacts a gas phase space, thereby obtaining an electrode substrate subjected to single-sided surface corrosion.

[0021] The electrode substrate subjected to surface corrosion is reacted with a metal sulfate precursor solution. The electrode substrate subjected to surface corrosion is preferably subjected to post-treatment according to the present application, and the post-treatment is as follows: the electrode substrate subjected to surface corrosion is subjected to water washing.

[0022] After the post-treatment, the reaction with the metal sulfate precursor solution is performed at a temperature of 20-60°C for 2-3 h, and the electrode substrate surface undergoes deconstruction of the metal hydroxide; the above reaction system is co-precipitated under alkaline conditions until the reaction endpoint is reached, and the alkaline conditions are provided by dilute ammonia water. The metal ion core in the reaction system has a strong affinity for anions, the electrode substrate surface undergoes a composite reaction of the electrode substrate metal and the metal in the metal sulfate, the sulfate ions form a protective layer on the surface of the catalytic layer, a catalytic layer with a layered double hydroxide-sulfate composite structure is formed, and a hydrogen production electrode is obtained.

[0023] ​​​​​​In one embodiment, after the decomposition of the metal hydroxide on the surface of the electrode substrate, the reaction system is reacted with an alkaline solution under the protection of a reducing atmosphere, which can be hydrogen.

[0024] In one embodiment, the electrode substrate with surface corrosion is reacted with a metal sulfate precursor and a Na2SO4 solution, the concentration of the metal sulfate precursor is 0.3-1.5 mol / L, the concentration of the Na2SO4 solution is 0.5-1 mol / L, the reaction time is 2-3 h, the metal hydroxide on the surface of the electrode substrate is decomposed, and the reaction formula is as follows:

[0025] M1(OH)2+2H + =M1 2+ +2H2O;

[0026] M1(OH)3+3H + =M1 3+ +3H2O;

[0027] wherein M1 is an electrode substrate metal element, preferably one or more of iron, nickel, cobalt and molybdenum;

[0028] After the reaction is completed, dilute ammonia is added dropwise into the reaction system under the protection of a reducing atmosphere, a catalytic layer is formed on the surface of the electrode substrate, and a hydrogen production electrode is obtained. The dilute ammonia and the mixed solution are compounded on the surface of the electrode substrate, and the reaction formula is as follows:

[0029] M1 2+ +M2 2+ +OH - +SO4 2- +Na + →(M1(OH) a ) x -Na + y -(M2(OH) b ) z -(SO4 2- ) y / 2 ;

[0030] wherein M1 is an electrode substrate metal element, M2 is a metal element in the metal sulfate, preferably one or more of iron, nickel, cobalt and molybdenum; a and b are independently 2, 3, 4 or 5; x and z satisfy the following relationship: (2-a)x+(3-b)z=0; y is 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0031] The hydrogen production electrode provided by the application has a simple preparation method, and a catalytic layer with a layered composite bimetallic hydroxide-sulfate composite structure is generated in situ on the surface of the electrode substrate through corrosion of the surface of the electrode substrate and co-deposition with a metal sulfate, the catalytic layer has high specific surface area and porosity.

[0032] The application further provides an electrolytic cell, and the battery or electrolytic cell comprises the hydrogen production electrode described in the technical solution.

[0033] In one embodiment, the hydrogen production electrode described in the technical solution is used as a cathode and an anode of an electrolytic hydrogen production unit, and is prepared into an electrolytic cell together with a hydrogen production diaphragm and an electrolyte to perform electrolytic hydrogen production.

[0034] The application further provides an electrolytic cell, and the battery or electrolytic cell comprises the hydrogen production electrode described in the technical solution.

[0035] In one embodiment, the hydrogen production electrode described in the technical solution is used as a cathode and an anode of an electrolytic hydrogen production unit, and is prepared into an electrolytic cell together with a hydrogen production diaphragm and an electrolyte to perform electrolytic hydrogen production.

[0036] The hydrogen production electrode provided by the application has a simple preparation method, and a catalytic layer with a layered composite bimetallic hydroxide-sulfate composite structure is generated in situ on the surface of the electrode substrate through corrosion of the surface of the electrode substrate and co-deposition with a metal sulfate, the catalytic layer has high specific surface area and porosity. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only embodiments of the application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0038] Figure 1 The preparation method flowchart of the hydrogen production electrode. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0040] Embodiment 1:

[0041] Referring to Figure 1 , Figure 1 The preparation method flowchart of the hydrogen production electrode, the preparation method of the hydrogen production electrode provided by the present application specifically comprises the following steps:

[0042] 1) Electrode substrate surface corrosion: taking a foam nickel with a thickness of 500 μm as an electrode substrate, the electrode substrate is pretreated and washed with water, ethanol and 0.1 mol / L dilute hydrochloric acid for 3 times respectively. The pretreated electrode substrate is soaked in a 0.5 mol / L NaCl solution for 13 h to obtain an electrode substrate after surface corrosion.

[0043] 2) Electrode substrate and catalytic layer composite preparation: the electrode substrate after surface corrosion obtained in step 1) is washed with water for 3 times, and then the electrode substrate is soaked in a mixed solution of 0.3 mol / L ferric sulfate precursor and 1 mol / L Na2SO4, for 3 h, and the metal hydroxide on the surface of the electrode substrate is deconstructed. Under the protection of hydrogen in a reducing atmosphere, 0.05 mol / L dilute ammonia is added dropwise to the solution under mechanical stirring (stirring reaction kettle, rotation speed is 300 rpm), until the reaction reaches the end point (pH=8), the solution undergoes precipitation reaction, and a catalytic layer is formed on the surface of the electrode substrate, to obtain a composite of the electrode substrate and the catalytic layer, and a hydrogen production electrode is obtained. The catalytic layer is a layered double hydroxide-sulfate composite structure, and its structural formula is Ni(OH)2-Na + 4-Fe(OH)3-(SO4 2- )2, with a thickness of 200 nm.

[0044] Embodiment 2:

[0045] The preparation method of the hydrogen production electrode specifically comprises the following steps:

[0046] 1) Electrode substrate surface corrosion: The electrode substrate was a foam nickel with a thickness of 500 μm, which was washed with water, ethanol and 0.2 mol / L dilute hydrochloric acid for 3 times, respectively. The electrode substrate was placed on a support, and the support was placed in a 1 mol / L NaCl solution, so that the lower surface of the electrode substrate contacted the NaCl solution and the upper surface contacted air. Surface corrosion was carried out for 12 h, and a surface-corroded electrode substrate was obtained.

[0047] 2) Electrode substrate and catalytic layer composite preparation: The surface-corroded electrode substrate obtained in step 1) was washed with water for 3 times, and then the electrode substrate was placed on a support, and the support was placed in a reaction vessel, so that the lower surface of the substrate contacted a mixed solution of 0.3 mol / L iron sulfate precursor and 1 mol / L sodium sulfate, and the upper surface contacted a gas phase space. The reaction was carried out for 2 h. Under the protection of a reducing atmosphere of hydrogen, 0.05 mol / L dilute ammonia was added dropwise to the solution under mechanical stirring (stirring the reaction kettle at a speed of 300 rpm) until the reaction reached the end point (pH = 9). A catalytic layer was formed on the surface of the electrode substrate, and an electrode substrate and catalytic layer composite was obtained, thereby obtaining a hydrogen production electrode. The specific structure of the catalytic layer was a layered double hydroxide-sulfate composite structure, and the structural formula was Ni(OH)2-Na + 4-Fe(OH)3-(SO4 2- )2, and the thickness was 400 nm.

[0048] Example 3:

[0049] Electrolytic hydrogen production performance test

[0050] A diaphragm, a cathode and an anode with the same material were used to assemble an electrolytic hydrogen production unit. The hydrogen production electrode obtained in Example 1 and a commercially available platinum-carbon electrode were used as the cathode and the anode, respectively. A commercially available Zirfon membrane with a thickness of 100 microns was used as the diaphragm. The current density in the electrolytic hydrogen production unit was 100 A / m 2 , and the electrolyte was seawater and pure water, respectively. The voltage of the electrolytic hydrogen production unit was measured at 0 h and 144 h, respectively.

[0051] The results are shown in Table 1, which is the hydrogen production effect of the hydrogen production electrode.

[0052] Table 1 Hydrogen production effect of hydrogen production electrode

[0053]

[0054] The results show that the hydrogen production electrode has high stability in seawater environment, and the original electrochemical activity of unit 1 can be maintained after running in seawater for 144 hours. The voltage of unit 1 and unit 3 shows that the high concentration of chloride ions in seawater has little effect on the electrolysis performance of the hydrogen production electrode obtained by the application. The voltage of unit 1 and unit 2 shows that the hydrogen production performance of the hydrogen production electrode obtained by the application is equivalent to that of the commercially available platinum-carbon electrode in the early stage of electrolytic hydrogen production, but the stability of the hydrogen production electrode obtained by the application in seawater is higher than that of the commercially available platinum-carbon electrode, which can effectively reduce the negative impact of chloride ions in seawater and improve the hydrogen production activity of electrolytic hydrogen production.

[0055] The above examples are only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A hydrogen producing electrode, characterized by, The electrode substrate and a catalytic layer formed on the surface of the electrode substrate; The catalytic layer is formed by a layered double hydroxide-sulfate complex; The layered double hydroxide-sulfate complex has the following structure: (M1(OH) a ) x -Na + y -(M2(OH) b ) z -(SO4 2- ) y / 2 ; wherein M1 is iron, nickel, cobalt or molybdenum, and is a divalent ion; M2 is iron, nickel, cobalt or molybdenum, and is a trivalent ion; and M1 and M2 are not the same; a and b are independently 2, 3, 4 or 5; x and z satisfy the following relationship: (2-a)x+(3-b)z=0; y is 2, 3, 4, 5, 6, 7, 8, 9 or 10.

2. The hydrogen evolution electrode of claim 1, wherein The electrode substrate is one or more of iron, nickel, cobalt and molybdenum.

3. The hydrogen evolution electrode of claim 1, wherein The thickness of the electrode substrate is 100-500 μm, and the thickness of the catalytic layer is 50-500 nm.

4. A method of producing the hydrogen electrode of claim 1, characterized by, The method comprises the following steps: reacting the surface-etched electrode substrate with a metal sulfate precursor solution, and then co-precipitating under alkaline conditions to form a catalytic layer on the surface of the electrode substrate, thereby obtaining a hydrogen production electrode; The metal in the electrode substrate is not the same as the metal in the metal sulfate precursor. The surface etching is specifically surface etching of the electrode substrate with a NaCl solution having a concentration of 0.5-1 mol / L.

5. The method of claim 4, wherein the hydrogen electrode is prepared by the steps of: The etching time is 12-24 h, and the concentration of the metal sulfate precursor is 0.3-1.5 mol / L.

6. The method of claim 4, wherein the hydrogen electrode is prepared by the steps of: The alkaline condition is provided by dilute ammonia water.

7. The method of claim 4, wherein the hydrogen electrode is prepared by the steps of: The method further comprises pretreating the electrode substrate, and the pretreatment comprises sequentially washing the electrode substrate with water, alcohol and acid.

8. An electrolytic cell comprising the hydrogen production electrode according to any one of claims 1-3.

9. A battery comprising the hydrogen production electrode according to any one of claims 1-3.

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