Catalytic electrode for hydrogen production by electrolysis of water, preparation method of catalytic electrode, electrolytic bath and system for hydrogen production by electrolysis of water

Abstract

The embodiment of the invention provides a water electrolysis hydrogen production catalytic electrode and a preparation method thereof, an electrolytic bath and a water electrolysis hydrogen production system.The provided water electrolysis hydrogen production catalytic electrode comprises a conductive substrate and a catalytic material layer deposited on the conductive substrate, the catalytic material layer comprises a nickel-based material, the surface of the catalytic material layer is provided with mountain-chain-shaped protrusions, and the mountain-chain-shaped protrusions are arranged on the surface of the catalytic material layer. The nickel-based material is used as the catalytic material layer, and mountain chain-shaped bulges are formed on the surface of the nickel-based material, so that not only can better binding force between the catalytic material layer and the conductive substrate be ensured, but also more active sites can be obtained on the surface of the catalyst, and the catalyst material shows better catalytic activity; therefore, the technical problem that an existing water electrolysis hydrogen production catalytic electrode cannot effectively give consideration to catalytic activity and stability can be effectively solved. In addition, the catalytic electrode for hydrogen production by electrolysis of water provided by the embodiment of the invention does not need to use noble metal, so that the production cost is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of water electrolysis hydrogen production, and in particular to a water electrolysis hydrogen production catalytic electrode and a preparation method thereof, an electrolyzer and a water electrolysis hydrogen production system. Background Art

[0002] As the core equipment for producing hydrogen by electrolysis of water, hydrogen electrolyzers are mainly divided into alkaline hydrogen electrolyzers (ALK), proton exchange membrane hydrogen electrolyzers (PEM) and solid oxide water electrolysis devices. Among them, the key to the hydrogen production efficiency of alkaline hydrogen electrolyzers (ALK) lies in their electrodes.

[0003] Existing catalytic electrodes for hydrogen production by water electrolysis are generally prepared by thermal spraying, electrodeposition, and hydrothermal method with auxiliary methods such as vapor deposition and etching. However, the catalytic electrodes for hydrogen production by water electrolysis prepared by the above methods cannot effectively take into account both catalytic activity and stability. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a catalytic electrode for hydrogen production by electrolysis of water and a preparation method thereof, an electrolyzer and a system for hydrogen production by electrolysis of water, so as to solve the technical problem that the existing catalytic electrode for hydrogen production by electrolysis of water cannot effectively take into account both catalytic activity and stability.

[0005] In order to solve the above problems, the present invention is achieved through the following technical solutions:

[0006] The present invention proposes a catalytic electrode for producing hydrogen by electrolyzing water, which comprises a conductive substrate and a catalytic material layer deposited on the conductive substrate, wherein the catalytic material layer comprises a nickel-based material, and the surface of the catalytic material layer has mountain-like protrusions.

[0007] Furthermore, in the catalytic electrode, the mountain-shaped protrusions have holes; the pore size of the holes is 10 to 30 μm, and / or the porosity of the mountain-shaped protrusions is 30 to 40%, and / or the area of ​​the mountain-shaped protrusions on the surface of the catalytic material layer accounts for 25 to 40%.

[0008] Furthermore, in the catalytic electrode, the nickel-based material is a nickel-cobalt-phosphorus alloy.

[0009] Furthermore, the overpotential of the catalytic electrode is 50-105 mV, and / or the electrochemical surface area of ​​the catalytic material layer per square centimeter is 100-150 cm 2 , and / or at 2000A / cm 2 When operated at a current density of , the voltage change of the catalytic electrode is less than 0.07 mV per hour.

[0010] Furthermore, in the catalytic electrode, in the catalytic material layer, the mass fraction of nickel element is 50% to 60%, the mass fraction of cobalt element is 25% to 35%, and the mass fraction of phosphorus element is 5% to 15%.

[0011] Furthermore, in the catalytic electrode, the catalytic material layer further includes sulfur and oxygen, and the mass fraction of the sulfur is 0-0.5%, and the mass fraction of the oxygen is 0-1%.

[0012] Furthermore, in the catalytic material layer, the mass ratio of nickel element, cobalt element and phosphorus element is (6-7):(3-3.5):1.

[0013] Furthermore, in the catalytic electrode, the material of the conductive substrate is metallic nickel; and / or

[0014] The conductive substrate includes one or more of a nickel mesh, a nickel foam, a nickel sheet, a nickel block, and a nickel strip.

[0015] The present invention also proposes a method for preparing a catalytic electrode for producing hydrogen by electrolysis of water, which comprises:

[0016] Placing the conductive substrate as a cathode in an electrodeposition solution for electrodeposition treatment; wherein the electrodeposition solution comprises a nickel source, a cobalt source and a phosphorus source;

[0017] The conductive substrate after the electrodeposition treatment is pickled to obtain a catalytic electrode for hydrogen production by electrolysis of water.

[0018] Furthermore, in the preparation method, the molar concentration of the nickel source is 0.7-0.9 mol / L, the molar concentration of the cobalt source is 0.17-0.23 mol / L, and the molar concentration of the phosphorus source is 0.48-0.72 mol / L.

[0019] Furthermore, in the preparation method, the nickel source includes one or more of nickel sulfate, nickel chloride, nickel acetate, and nickel sulfamate; and / or

[0020] The cobalt source includes one or more of cobalt sulfate, cobalt chloride, cobalt acetate, and cobalt nitrate; and / or

[0021] The phosphorus source includes one or more of sodium hypophosphite and phosphoric acid.

[0022] Furthermore, in the preparation method, the electrodeposition solution further comprises a complexing agent and an electrodeposition additive; and / or

[0023] The molar concentration of the complexing agent is 0.1-0.16 mol / L, and the molar concentration of the electrodeposition additive is 0.0017-0.008 mol / L.

[0024] Furthermore, in the preparation method, the complexing agent includes one or more of sodium citrate and sodium acetate; and / or

[0025] The electrodeposition additives include one or more of saccharin and sodium dodecyl sulfate.

[0026] Furthermore, in the preparation method, the pH of the electrodeposition solution is 2-3.

[0027] Furthermore, in the preparation method, the current density applied during the electrodeposition treatment is 100 to 500 mA / cm 2 , power-on time 3 to 12 minutes.

[0028] Furthermore, in the preparation method, the acid solution used in the pickling treatment is sulfuric acid.

[0029] Furthermore, in the preparation method, in the pickling treatment, the mass concentration of the sulfuric acid is 20% to 30%, and the pickling time is 10 to 30 seconds.

[0030] The present invention also provides an electrolytic cell, which comprises the above-mentioned catalytic electrode.

[0031] The present invention also provides a water electrolysis hydrogen production system, which includes the above-mentioned electrolytic cell.

[0032] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0033] In an embodiment of the present invention, a catalytic electrode for producing hydrogen by electrolysis of water is provided, comprising a conductive substrate and a catalytic material layer deposited on the conductive substrate, wherein the catalytic material layer comprises a nickel-based material, and the surface of the catalytic material layer has mountain-like protrusions. Among them, using a nickel-based material as the catalytic material layer and forming mountain-like protrusions on its surface can not only ensure that the catalytic material layer has a better bonding force with the conductive substrate, but also obtain more active sites on the catalyst surface, so that the catalyst material exhibits better catalytic activity, thereby effectively solving the technical problem that the existing catalytic electrode for producing hydrogen by electrolysis of water cannot effectively balance catalytic activity and stability; in addition, the catalytic electrode for producing hydrogen by electrolysis of water provided in an embodiment of the present invention does not require the use of precious metals, and its production cost is relatively low.

[0034] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of the catalytic electrode for producing hydrogen by electrolysis of water provided in an embodiment of the present invention;

[0036] Figure 2It is a flow chart of the method for preparing a catalytic electrode for producing hydrogen by electrolysis of water provided in an embodiment of the present invention;

[0037] Figure 3 This is an appearance diagram of the catalytic electrode for hydrogen production by electrolysis produced in Example 1 of the present invention;

[0038] Figure 4 yes Figure 3 SEM image of the black edge area in the middle;

[0039] Figure 5 yes Figure 3 SEM image of the middle grey inner area;

[0040] Figure 6 is a scanning electron microscope image of the catalytic electrode for hydrogen production by electrolysis produced in Example 1 of the present invention;

[0041] Figure 7 yes Figure 6 Scanning electron microscope image of the mountain-like protrusions in the middle;

[0042] Figure 8 This is a scanning electron microscope image of the catalytic electrode for hydrogen production by electrolysis prepared in Comparative Example 2 of the present invention;

[0043] Fig. 9 This is a surface energy spectrum analysis diagram of the catalytic electrode for hydrogen production by electrolysis produced in Example 1 of the present invention;

[0044] Fig.10 This is a surface energy spectrum analysis diagram of the catalytic electrode for hydrogen production by electrolysis prepared in Comparative Example 2 of the present invention;

[0045] Fig.11 It is a linear potential comparison diagram of the catalytic electrode for hydrogen production by electrolysis prepared in Example 1 of the present invention, the substrate and Comparative Example 2;

[0046] Fig.12 It is a voltage variation diagram of the catalytic electrodes for hydrogen production by electrolysis produced in Example 1 of the present invention and Comparative Example 3 after continuous operation for 500 hours.

[0047] Reference numerals:

[0048] 11-conductive substrate, 12-catalytic material layer, 13-mountain-shaped protrusions. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The embodiment of the present invention provides a catalytic electrode for producing hydrogen by electrolysis of water, such as Figure 1As shown, it includes a conductive substrate 11 and a catalytic material layer 12 deposited on the conductive substrate 11. The catalytic material layer 12 includes a nickel-based material, and the surface of the catalytic material layer has mountain-shaped protrusions 13.

[0051] The catalytic electrode for hydrogen evolution by water electrolysis provided in the embodiment of the present invention can be directly installed in a water electrolysis hydrogen production electrolyzer as a cathode for use.

[0052] Among them, using nickel-based material as the catalytic material layer and forming mountain-like protrusions on its surface can not only ensure that the catalytic material layer has better bonding with the conductive substrate, but also obtain more active sites on the catalyst surface, so that the catalyst material exhibits better catalytic activity, thereby effectively solving the technical problem that the existing water electrolysis hydrogen production catalytic electrode cannot effectively take into account catalytic activity and stability; in addition, the water electrolysis hydrogen production catalytic electrode provided in the embodiment of the present invention does not require the use of precious metals, and its production cost is relatively low.

[0053] Optionally, the surface and interior of the mountain-shaped protrusions have holes, which can be formed by short-time reaction between pickling and metal after electrodeposition, and can effectively increase the chemical reaction area of ​​the electrode material, thereby improving its catalytic activity. Optionally, the pore size of the pores is 10 to 30 μm, for example, one of 10 μm, 12 μm, 15 μm, 20 μm, 25 μm, 30 μm, or any two of the range values.

[0054] Optionally, in one embodiment, the porosity of the mountain-shaped protrusions is 30-40%, which can effectively increase the chemical reaction area on the surface of the electrode material, and also enable the porous mountain-shaped protrusions to still be stably attached to the surface of the catalytic material layer, thereby ensuring the excellent catalytic performance and stability of the electrode material. Optionally, the porosity of the mountain-shaped protrusions can be in the range of 30%, 35%, 40%, or any two of them.

[0055] In an embodiment of the present invention, the mountain-shaped protrusions are distributed on the surface of the catalytic material layer. Optionally, in one embodiment, the area of ​​the mountain-shaped protrusions on the surface of the catalytic material layer accounts for 25-40%, which can effectively increase the reaction area of ​​the catalytic material layer while ensuring the overall structural stability of the catalytic electrode, and the prepared catalytic material has higher activity. Optionally, the area of ​​the mountain-shaped protrusions on the surface of the catalytic material layer can be 25%, 28%, 30%, 35%, 40%, or any two of the range values.

[0056] Optionally, the nickel-based material may specifically be a nickel-cobalt-phosphorus alloy, which not only has a high catalytic activity for producing hydrogen by electrolysis of water, but also can maintain strong stability after forming mountain-like protrusions.

[0057] Optionally, in practical applications, nickel-cobalt-phosphorus alloy can be deposited on a conductive substrate by electrodeposition or the like to form the above-mentioned catalytic material layer, and can be etched by pickling or the like to form mountain-like protrusions on the surface of the catalytic material layer, thereby reforming the surface structure of the catalytic material layer deposited on the conductive substrate, obtaining more active sites on its surface, and being able to effectively enhance the catalytic performance of the electrode while ensuring that the catalytic material layer is firmly bonded to the conductive substrate.

[0058] In the embodiment of the present invention, the catalytic material layer is mainly formed of a nickel-cobalt-phosphorus alloy, that is, mainly composed of nickel, cobalt and phosphorus, so that the catalytic material layer has excellent alkaline electrocatalytic hydrogen evolution performance.

[0059] Optionally, in one embodiment, in the above-mentioned catalytic material layer, the mass fraction of nickel element is 50% to 60%, the mass fraction of cobalt element is 25% to 35%, and the mass fraction of phosphorus element is 5% to 15%.

[0060] In this embodiment, nickel, cobalt and phosphorus are configured according to the above-mentioned mass fractions to form the above-mentioned catalytic material layer. Each element can be effectively graded, which increases the electrochemical properties of the catalytic material layer in alkaline electrolyte and its bonding performance with the conductive substrate. It can effectively take into account its conductivity and stability. It not only has excellent electrochemical stability, but also has a long service life.

[0061] Optionally, in a specific embodiment, in the above-mentioned catalytic material layer, the mass ratio between nickel element, cobalt element and phosphorus element is (6-7):(3-3.5):1, which makes the grading of the three elements more reasonable, not only the electron transmission rate is higher, but also the bonding performance with the conductive substrate is stronger.

[0062] Optionally, in one embodiment, the catalytic material layer further comprises sulfur and oxygen, and the mass fraction of the sulfur is 0-0.5%, and the mass fraction of the oxygen is 0-1%. In this embodiment, the sulfur and oxygen can react with cobalt and nickel in the form of sulfate radicals to form sulfates, and etch the mountain-like protrusions on the catalytic material layer, thereby increasing the catalytic active sites; and the sulfates can be compounded with the nickel-cobalt-phosphorus alloy on the surface of the catalytic material layer.

[0063] In the embodiment of the present invention, the conductive substrate is made of a material that is conductive and easy to combine with a nickel-based material. Optionally, the conductive substrate is made of metal nickel, which not only has excellent conductivity, but also is easy to combine with a nickel-based material with nickel as the main component, which can further ensure the bonding performance between the catalytic material layer and the conductive substrate, and ensure the catalytic stability of the electrode.

[0064] Optionally, in one embodiment, the conductive substrate includes one or more of nickel mesh, nickel foam, nickel sheet, nickel block, and nickel strip, that is, the conductive substrate can be in various forms such as nickel mesh, nickel foam, nickel sheet, nickel block, and nickel strip.

[0065] Optionally, in one embodiment, the electrochemical surface area of ​​the catalyst material layer is 100 to 150 cm2. 2 , that is, it can have more active temperatures while ensuring the stability of catalytic performance, thereby achieving excellent hydrogen evolution catalytic performance. For example, the electrochemical surface area of ​​each square centimeter of the catalytic material layer can be 100 cm 2 、110cm 2 、120cm 2 、130cm 2 、140cm 2 、150cm 2 The range value of one or both of them.

[0066] In the embodiment of the present invention, a nickel-based material is used as the main body of the catalytic material layer, and its surface has mountain-like protrusions, so that its overpotential is 50-105mV, for example, it can be one of 50mV, 70mV, 100mV, 105mV or any two of the range values.

[0067] The catalytic electrode provided in the embodiment of the present invention can effectively improve its catalytic life by providing mountain-shaped protrusions on the surface of the catalytic material layer with nickel-based material as the main body. 2 During operation at a current density of 2000A / cm, the voltage change of the catalytic electrode was less than 0.07mV per hour. 2 It can run stably for more than 500h at a current density of 1.

[0068] The present invention also provides a method for preparing a catalytic electrode for hydrogen production by electrolysis of water, wherein: Figure 2 As shown, it includes steps 201 to 202:

[0069] Step 201, placing a conductive substrate as a cathode in an electrodeposition solution for electrodeposition treatment; wherein the electrodeposition solution includes a nickel source, a cobalt source and a phosphorus source;

[0070] Step 202: acid-wash the conductive substrate after the electrodeposition treatment to obtain a catalytic electrode for producing hydrogen by electrolysis of water.

[0071] In the embodiment of the present invention, a nickel-cobalt-phosphorus alloy is first formed on the surface of a conductive substrate by electrodeposition, and then the reaction active sites of the nickel-cobalt-phosphorus alloy are increased by pickling, so that its microstructure is in the shape of mountain-like protrusions on a plane, thereby obtaining an efficient catalytic electrode for hydrogen evolution by electrolysis of water.

[0072] In the above preparation method, only one electrodeposition treatment and one pickling treatment are required to obtain a high-efficiency hydrogen evolution catalytic electrode, which is time-saving, simple in process, and highly applicable, and can be applied to the preparation method using nickel alloy as catalyst material; at the same time, because only one electrodeposition method is required to simultaneously deposit nickel alloy and metal phosphide, the process is simpler, less energy is consumed, and more environmentally friendly. The obtained electrode is a two-layer structure of a conductive substrate loaded with nickel-cobalt-phosphorus alloy, which makes the electrode structure simpler and more stable, and is suitable for the hydrogen evolution process in the process of hydrogen production by electrolysis of water.

[0073] In the above step 201, an electrodeposition liquid is prepared, a cleaned conductive substrate is used as a cathode, and an anode is one of nickel metal, graphite, and platinum metal. Then, current is applied to the cathode and the anode. After a period of power supply, the cathode and the anode are taken out and washed with water to complete the electrodeposition process.

[0074] Among them, when cleaning the conductive substrate before electrodeposition treatment, the surface oil stains can be effectively removed after cleaning with acetone and water.

[0075] The conductive substrate is made of a material that is conductive and easy to combine with the nickel-cobalt-phosphorus alloy. Optionally, the conductive substrate is made of metal nickel, which not only has excellent conductivity, but also is easy to combine with the nickel-cobalt-phosphorus alloy with nickel as the main component, which can further ensure the bonding strength between the catalytic material layer and the conductive substrate, and ensure the catalytic stability of the electrode.

[0076] Optionally, in one embodiment, the conductive substrate includes one or more of nickel mesh, nickel foam, nickel sheet, nickel block, and nickel strip, that is, the conductive substrate can be in various forms such as nickel mesh, nickel foam, nickel sheet, nickel block, and nickel strip.

[0077] The nickel source, cobalt source and phosphorus source in the electrodeposition solution can be deposited on the surface of the conductive substrate to form a nickel-cobalt-phosphorus alloy under the action of electrodeposition.

[0078] Optionally, in one embodiment, the nickel source includes one or more of nickel sulfate, nickel chloride, nickel acetate, and nickel sulfamate. Optionally, in a specific embodiment, the nickel source includes nickel sulfate and nickel chloride.

[0079] Alternatively, in one embodiment, the cobalt source includes one or more of cobalt sulfate, cobalt chloride, cobalt acetate, and cobalt nitrate. Alternatively, in a specific embodiment, the cobalt source includes cobalt sulfate.

[0080] Optionally, in one embodiment, the phosphorus source includes one or more of sodium hypophosphite and phosphoric acid.

[0081] Optionally, in one embodiment, the molar concentration of the nickel source is 0.7-0.9 mol / L, for example, it can be one of 0.7 mol / L, 0.8 mol / L, 0.9 mol / L or any two of the range values; the molar concentration of the cobalt source is 0.17-0.23 mol / L, for example, it can be one of 0.17 mol / L, 0.18 mol / L, 0.19 mol / L, 0.2 mol / L, 0.21 mol / L, 0.22 mol / L, 0.23 mol / L or any two of the range values; the molar concentration of the phosphorus source is 0.48-0.72 mol / L, for example, it can be one of 0.48 mol / L, 0.5 mol / L, 0.55 mol / L, 0.6 mol / L, 0.65 mol / L, 0.7 mol / L, 0.72 mol / L or any two of the range values.

[0082] Under the above concentration ratio, nickel, cobalt and phosphorus elements can be effectively graded through electrodeposition, which increases the electrochemical properties of the formed catalytic material layer in alkaline electrolyte and its bonding performance with the conductive substrate, and can effectively take into account its conductivity and stability. It not only has excellent electrochemical stability, but also has a long service life.

[0083] Under the above concentration ratio, in the formed catalytic material layer, the mass fraction of nickel element is 50% to 60%, the mass fraction of cobalt element is 25% to 35%, the mass fraction of phosphorus element is 5% to 15%, and the mass ratio between nickel element, cobalt element and phosphorus element is (6 to 7): (3 to 3.5): 1, which makes the grading of the three elements more reasonable, not only the electron transmission rate is higher, but also the bonding performance with the conductive substrate is stronger.

[0084] Optionally, in one embodiment, the electrodeposition solution further includes a ligand and an electrodeposition additive. The ligand can form a complex with nickel, cobalt and other ions to dissolve more nickel and cobalt sources, thereby increasing Ni 2+ 、Co 2+ ion concentration; while electrodeposition additives can reduce the occurrence of side reactions and increase the bonding strength between the nickel-cobalt-phosphorus alloy material and the substrate.

[0085] Wherein, the above-mentioned ligand includes one or more of sodium citrate and sodium acetate, which can form complexes with cobalt and nickel ions, respectively. Optionally, in one embodiment, the molar concentration of the above-mentioned ligand is 0.1-0.16 mol / L, that is, it can dissolve enough nickel source and cobalt source to form nickel-cobalt-phosphorus alloy, that is, the concentration of nickel source and cobalt source is promoted to 0.7-0.9 mol / L and 0.17-0.23 mol / L.

[0086] Optionally, in a specific embodiment, the molar concentration of the above-mentioned ligand can be in the range of one or any two of 0.1mol / L, 0.11mol / L, 0.12mol / L, 0.13mol / L, 0.14mol / L, 0.15mol / L, 0.16mol / L.

[0087] Optionally, in a specific embodiment, the above-mentioned complexing agent includes sodium citrate and sodium acetate; wherein the molar concentration of sodium citrate is 0.03-0.05 mol / L, for example, it can be 0.03 mol / L, 0.04 mol / L, 0.05 mol / L; the molar concentration of sodium acetate is 0.07-0.11 mol / L, for example, it can be one of 0.07 mol / L, 0.08 mol / L, 0.09 mol / L, 0.1 mol / L, 0.11 mol / L or any two of the range values.

[0088] The electrodeposition additive includes one or more of saccharin and sodium dodecyl sulfate. Optionally, in one embodiment, the molar concentration of the electrodeposition additive is 0.0017-0.008 mol / L, which can effectively reduce the occurrence of side reactions and increase the bonding strength between the nickel-cobalt-phosphorus alloy material and the substrate.

[0089] Optionally, in a specific embodiment, the molar concentration of the above-mentioned electrodeposition additive can be one or any two of 0.0017mol / L, 0.002mol / L, 0.003mol / L, 0.004mol / L, 0.0017mol / L, 0.005mol / L, 0.006mol / L, 0.007mol / L, 0.008mol / L.

[0090] Optionally, in a specific embodiment, the electrodeposition additive includes saccharin and sodium dodecyl sulfate; wherein the molar concentration of saccharin is 0.001-0.005 mol / L, for example, it can be one of 0.01 mol / L, 0.02 mol / L, 0.03 mol / L, 0.04 mol / L, 0.05 mol / L or any two of the range values; the molar concentration of sodium dodecyl sulfate is 0.0007-0.003 mol / L, for example, it can be one of 0.0007 mol / L, 0.001 mol / L, 0.002 mol / L, 0.003 or any two of the range values.

[0091] In the preparation method provided in the embodiment of the present invention, the pH of the electrodeposition solution is 2-3, which can dissolve enough nickel and cobalt metal ions to participate in the electrodeposition reaction, while preventing the substrate from being damaged by excessive acid.

[0092] Optionally, in the above-mentioned electrodeposition process, the applied current density is 100-500 mA / cm 2 The power-on time is 3 to 12 minutes, that is, a catalytic material layer with nickel-cobalt-phosphorus alloy as the main body can be effectively deposited on the surface of the conductive substrate. The alloy layer is prepared by electrodeposition technology, and its surface morphology is relatively flat in the microscopic state, with some small protrusions.

[0093] In the above step 202, the conductive substrate after the electrodeposition treatment is cleaned with water and then immersed in an acid solution for acid etching. The pickling solution should be a strong acid, specifically hydrochloric acid or sulfuric acid, which can convert the small surface bumps into mountain-like protrusions without affecting the bonding strength between the nickel-cobalt-phosphorus alloy layer and the conductive substrate, thereby obtaining more active sites and making the catalytic material layer show better catalytic activity, thereby effectively solving the technical problem that the existing water electrolysis hydrogen production catalytic electrode cannot effectively take into account the catalytic activity and stability; in addition, the water electrolysis hydrogen production catalytic electrode provided in the embodiment of the present invention does not require the use of precious metals, and its production cost is relatively low.

[0094] In the above step 202, the electrode after pickling is taken out and washed with water to obtain a high-efficiency hydrogen evolution catalytic electrode. In a microscopic state, its surface morphology will have more mountain-like protrusions than the electrode that has only been subjected to electrodeposition treatment in step 201, and the surface becomes rougher, which effectively increases the active sites on the electrode surface. In addition, after pickling, the appearance of the above electrode is a double-circle structure, the outer circle is black and the circle layer is thin, and the inner circle is gray.

[0095] Optionally, in one embodiment, in the above-mentioned pickling treatment, the acid solution used is sulfuric acid, and the sulfate ions can react with cobalt and nickel to form sulfates, and etch the above-mentioned mountain-like protrusions on the catalytic material layer, thereby increasing the catalytic active sites; and the sulfates can be compounded with the nickel-cobalt-phosphorus alloy on the surface of the catalytic material layer.

[0096] Optionally, in a specific embodiment, during the pickling treatment, the mass concentration of sulfuric acid is 20% to 30%, and the pickling time is 10 to 30 seconds, which can effectively reform the surface structure of the catalytic material layer deposited on the conductive substrate, obtain more active sites on its surface, and effectively enhance the catalytic performance of the electrode while ensuring that the catalytic material layer is firmly bonded to the conductive substrate.

[0097] In the above specific embodiment, after the pickling with sulfuric acid, the catalytic material layer is made of nickel-cobalt-phosphorus alloy as the main body of the catalytic material layer, and also includes sulfur and oxygen elements, and the mass fraction of the sulfur element is 0-0.5%, and the mass fraction of the oxygen element is 0-1%. The surface of the catalytic material layer has mountain-like protrusions, and its overpotential is 50-105mV, and the electrochemical surface area of ​​the catalytic material layer per square centimeter is 100-150cm2 , it can have more active temperatures while ensuring the stability of catalytic performance, thereby achieving excellent hydrogen evolution catalytic performance.

[0098] The present invention also provides an electrolytic cell, which comprises the above-mentioned catalytic electrode.

[0099] The present invention also provides a water electrolysis hydrogen production system, which includes the above-mentioned electrolytic cell.

[0100] For the above-mentioned electrolyzer and water electrolysis hydrogen production system embodiments, they include the above-mentioned catalytic electrode and can achieve the same technical effects. In order to avoid repetition, they will not be described here. For relevant matters, please refer to the partial description of the catalytic electrode embodiment.

[0101] The present invention is described in detail below by way of examples.

[0102] Test method:

[0103] (1) Morphology test: The electrode surface morphology in this application is observed by scanning electron microscopy (SEM) at high magnification on the catalytic material layer on the electrode surface;

[0104] (2) Electrode surface element analysis test: In the process of observing the electrode surface morphology with a scanning electron microscope, an energy dispersive spectrometer (EDS) is used to analyze the various elemental components and percentage mass content on the electrode surface;

[0105] (3) Catalytic performance test: In electrochemistry, overpotential is directly related to the voltage efficiency of the electrochemical reaction. Overpotential is divided into oxygen evolution overpotential and hydrogen evolution overpotential. Oxygen evolution overpotential is positive and hydrogen evolution overpotential is negative. In the actual electrode development process, the lower the absolute value of the two, the better the electrode catalytic performance;

[0106] In this application, the overpotential was measured by linear sweep voltammetry (LSV) in an electrochemical workstation with the electrode prepared in this application as the working electrode, the platinum electrode as the counter electrode, and the mercury-mercury oxide electrode as the reference electrode in an electrolytic cell filled with 0.1 mol / L KOH solution (10 mA / cm was selected in this application). 2 ) is determined by the electrode potential under ). The overpotential measured in this application is the hydrogen evolution overpotential;

[0107] (4) Catalytic life test: The electrode prepared in this application was used as the cathode and the graphite electrode was used as the anode. A current density of 2000 A / m was passed into a beaker filled with a 30% KOH solution. 2 The current was tested continuously for 500 hours, and the voltage change before and after 500 hours of the experiment was calculated;

[0108] (5) Electrochemical surface area test: The electrochemical surface area is measured by measuring the static double-layer capacitance C of the electrode. DL , and then divided by the conversion coefficient. The electrochemical surface area is obtained by using an electrochemical workstation with the electrode prepared in this application as the working electrode, a platinum electrode as the counter electrode, and a mercury-mercury oxide electrode as the reference electrode. Cyclic voltammetry (CV) is used in an electrolytic cell filled with 0.1 mol / L KOH solution to measure the non-Faraday interval double-layer capacitance charge and discharge current corresponding to the cyclic voltammetry curve at five scanning speeds of 20 mV / s, 40 mV / s, 60 mV / s, 80 mV / s, and 100 mV / s. The electrochemical surface area is calculated after linear fitting.

[0109] Example 1

[0110] (1) Preparation of electrodeposition solution

[0111] 37.5 g of nickel sulfate hexahydrate, 9 g of nickel chloride hexahydrate, 8.8 g of sodium hypophosphite monohydrate, 5 g of phosphoric acid, 12.6 g of cobalt sulfate hexahydrate, 2.5 g of sodium acetate, 2.5 g of sodium citrate, 0.1 g of saccharin, and 0.1 g of sodium dodecyl sulfate were weighed respectively, dissolved in water, and 250 mL of electrodeposition solution was prepared, whose pH was 3.

[0112] (2) Electrodeposition treatment

[0113] A 40-mesh nickel mesh was cut into 2cm*2cm as a conductive substrate, and the conductive substrate was washed with acetone and water respectively and used as a cathode, and a pure nickel sheet was selected as an anode;

[0114] The electrodes were placed in the electrodeposition solution and a current of 1.6 A was applied to the cathode and anode. After 3 minutes of power-on, the cathode was taken out and washed with water for 30 seconds.

[0115] (3) Pickling treatment

[0116] The cathode cleaned with water was soaked in sulfuric acid with a mass concentration of 20%, taken out after soaking for 15 seconds, and washed with water to obtain a catalytic electrode.

[0117] Example 2

[0118] The difference between Example 2 and Example 1 is that in step (2), the 40-mesh nickel mesh is adjusted to 100-mesh nickel foam.

[0119] Example 3

[0120] The difference between Example 3 and Example 1 is that in step (2), the applied current is adjusted to 0.4 A and the power-on time is adjusted to 10 minutes.

[0121] Example 4

[0122] The difference between Example 4 and Example 1 is that in step (2), the applied current is adjusted to 1.2 A and the power-on time is adjusted to 10 minutes; in step (3), the immersion time is adjusted to 20 seconds.

[0123] Example 5

[0124] The difference between Example 5 and Example 2 is that in step (3), the mass concentration of sulfuric acid is adjusted to 25% and the soaking time is adjusted to 30 seconds.

[0125] Example 6

[0126] The difference between Example 6 and Example 1 is that in step (1), the weighed amounts of nickel sulfate hexahydrate, nickel chloride hexahydrate, sodium hypophosphite monohydrate, phosphoric acid, cobalt sulfate hexahydrate, sodium acetate, sodium citrate, saccharin, and sodium dodecyl sulfate are adjusted to 35 g, 9 g, 10 g, 6 g, 14 g, 3 g, 3 g, 0.12 g, and 0.11 g, respectively;

[0127] In step (2), the 40-mesh nickel mesh is adjusted to a 60-mesh nickel mesh.

[0128] Example 7

[0129] The difference between Example 7 and Example 1 is that in step (1), the weighed amounts of nickel sulfate hexahydrate, nickel chloride hexahydrate, sodium hypophosphite monohydrate, phosphoric acid, cobalt sulfate hexahydrate, sodium acetate, sodium citrate, saccharin, and sodium dodecyl sulfate are adjusted to 35 g, 8.75 g, 8.75 g, 3.75 g, 12.5 g, 2.5 g, 2.5 g, 0.05 g, and 0.05 g, respectively.

[0130] Example 8

[0131] The difference between Example 8 and Example 1 is that in step (1), the weighed amounts of nickel sulfate hexahydrate, nickel chloride hexahydrate, sodium hypophosphite monohydrate, phosphoric acid, cobalt sulfate hexahydrate, sodium acetate, sodium citrate, saccharin, and sodium dodecyl sulfate are adjusted to 45 g, 12.5 g, 12.5 g, 6.25 g, 16.25 g, 3.75 g, 3.75 g, 0.25 g, and 0.25 g, respectively.

[0132] Example 9

[0133] The difference between Example 9 and Example 1 is that in step (1), sodium acetate, sodium citrate, saccharin and dodecyl sulfuric acid are not added to the electrodeposition solution.

[0134] Example 10

[0135] The difference between Example 10 and Example 1 is that in step (1), the weighed amounts of phosphoric acid, sodium acetate and sodium citrate are adjusted to 6.25 g, 2.5 g and 2.5 g, and the pH of the electrodeposition solution is 2.

[0136] Embodiment 11

[0137] The difference between Example 11 and Example 1 is that in step (1), the weighing amount of phosphoric acid is adjusted to 3.75 g and the pH of the electrodeposition solution is adjusted to 3.

[0138] Example 12

[0139] The difference between Example 12 and Example 1 is that in step (2), the applied current is adjusted to 0.4A.

[0140] Embodiment 13

[0141] The difference between Example 13 and Example 1 is that in step (2), the applied current is adjusted to 2A.

[0142] Embodiment 14

[0143] The difference between Example 14 and Example 1 is that in step (2), the power-on time is 6 minutes.

[0144] Embodiment 15

[0145] The difference between Example 15 and Example 1 is that in step (2), the power-on time is 12 minutes.

[0146] Example 16

[0147] The difference between Example 16 and Example 1 is that in step (3), the mass concentration of sulfuric acid is adjusted to 30%.

[0148] Comparative Example 1

[0149] The difference between Comparative Example 1 and Example 1 is that in step (1), cobalt sulfate hexahydrate is not added to the electrodeposition solution.

[0150] Comparative Example 2

[0151] The difference between Comparative Example 2 and Example 1 is that step (2) is not performed.

[0152] Comparative Example 3

[0153] A hydrogen evolution electrode was purchased from the market, and a Raney nickel catalyst was thermally sprayed on a 40-mesh nickel screen.

[0154] Sample performance test:

[0155] The electrodes prepared in each embodiment and comparative example were subjected to morphology test, surface element analysis, catalytic performance test, catalytic life test and electrochemical surface test in turn, and the results are shown in Table 1. The appearance of the catalytic electrode for hydrogen production by electrolysis prepared in Example 1 is shown in Table 1. Figure 3 As shown, it is a double-circle structure, with black edges and thin circles, and gray inside. Scanning electron microscopy tests were performed on the edges and inside, and the structure is as follows Figures 4-5 As shown, the morphology test results of the electrolytic hydrogen production catalytic electrode prepared in Example 1 are as follows Figures 6-7 As shown, the morphology test results of the catalytic electrode for hydrogen production by electrolysis prepared in Comparative Example 2 are as follows Figure 8 As shown; the surface element analysis results of the electrolytic hydrogen production catalytic electrodes prepared in Example 1 and Comparative Example 2 are shown respectively Fig. 9 , 10 The linear potential scanning results of the catalytic electrode for hydrogen production by electrolysis prepared in Example 1 and Comparative Example 2 are shown as follows: Fig.11 As shown, the catalytic life test results of the catalytic electrodes for hydrogen production by electrolysis prepared in Example 1 and Comparative Example 3 are as follows Fig.12 shown.

[0156] Table 1

[0157]

[0158]

[0159] pass Figures 3 to 5 It can be seen that acid washing can transform the small protrusions on the surface of the catalytic electrode into mountain-like protrusions, and the porosity of the outer black area is significantly higher than that of the gray area, making the roughness of the black area significantly higher than that of the gray area. The rougher surface shows color difference in the macroscopic state due to the refraction of light.

[0160] Through Table 1 and Figures 4 to 7 By comparing Example 1 and Comparative Example 2, it can be seen that the small protrusions on the surface of the catalytic electrode can be transformed into mountain-like protrusions by acid pickling, and the surface and interior of the protrusions are covered with holes. By changing the surface morphology of the nickel-cobalt-phosphorus alloy layer, the alloy layer becomes rougher, effectively increasing the active sites on the electrode surface.

[0161] Through Table 1 and Figures 5-6 By comparing Example 1 and Comparative Example 2, it can be seen that after the catalytic electrode is pickled, part of the nickel-cobalt-phosphorus alloy layer attached to the surface thereof will react with sulfuric acid, and sulfate will be formed on the electrode surface and composited with the nickel-cobalt-phosphorus alloy layer.

[0162] By comparing the embodiments and the comparative examples in Table 1, it can be seen that the nickel-cobalt-phosphorus alloy is first formed on the surface of the conductive substrate by electrodeposition treatment, and then the reaction active sites of the nickel-cobalt-phosphorus alloy are increased by pickling, so that its microstructure is in the shape of mountain-like protrusions on the plane, thereby obtaining a high-efficiency catalytic electrode for hydrogen evolution by electrolysis of water; at the same time, when the nickel source, cobalt source, phosphorus source, ligand and electrodeposition additive are reasonably graded and moderately concentrated, and the pH of the electrodeposition solution, the electrodeposition treatment current density, the power-on time and the mass concentration of sulfuric acid are moderate, the performance of the obtained catalytic electrode is particularly good.

[0163] The catalytic electrode for producing hydrogen by electrolysis of water provided in the embodiment of the present invention can produce hydrogen at 2000A / m 2 It can run stably for more than 500 hours at a current density of 10 ...

[0164] To summarize, in the present embodiment, the provided catalytic electrode for hydrogen production by water electrolysis includes a conductive substrate and a catalytic material layer deposited on the conductive substrate, the catalytic material layer includes a nickel-cobalt-phosphorus alloy, and the surface of the catalytic material layer has mountain-like protrusions, wherein the nickel-cobalt-phosphorus alloy is used as the catalytic material layer and mountain-like protrusions are formed on its surface, which can not only ensure that the catalytic material layer has better bonding with the conductive substrate, but also obtain more active sites on the catalyst surface, so that the catalyst material exhibits better catalytic activity, thereby effectively solving the technical problem that the existing catalytic electrode for hydrogen production by water electrolysis cannot effectively take into account both catalytic activity and stability; in addition, the catalytic electrode for hydrogen production by water electrolysis provided in the embodiment of the present invention does not require the use of precious metals, and its production cost is relatively low.

[0165] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concept. Therefore, the claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0166] The above is a detailed introduction to a catalytic electrode for hydrogen production by electrolysis of water and a preparation method thereof, an electrolyzer and a hydrogen production system by electrolysis of water provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for a person skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A catalytic electrode for producing hydrogen by electrolysis of water, characterized in that: It comprises a conductive substrate and a catalytic material layer deposited on the conductive substrate. The catalytic material layer comprises a nickel-based material, and the surface of the catalytic material layer has mountain-shaped protrusions.

2. The catalytic electrode according to claim 1, characterized in that The mountain-shaped protrusions have holes; the pore diameter of the holes is 10-30 μm, and / or the porosity of the mountain-shaped protrusions is 30-40%, and / or the area of ​​the mountain-shaped protrusions on the surface of the catalytic material layer accounts for 25-40%.

3. The catalytic electrode according to claim 1, characterized in that The nickel-based material is a nickel-cobalt-phosphorus alloy.

4. The catalytic electrode according to claim 1, characterized in that The overpotential of the catalytic electrode is 50-105 mV, and / or the electrochemical surface area of ​​the catalytic material layer per square centimeter is 100-150 cm 2 , and / or at 2000A / cm 2 When operated at a current density of , the voltage change of the catalytic electrode is less than 0.07 mV per hour.

5. The catalytic electrode according to claim 3, characterized in that: In the catalytic material layer, the mass fraction of nickel element is 50% to 60%, the mass fraction of cobalt element is 25% to 35%, and the mass fraction of phosphorus element is 5% to 15%.

6. The catalytic electrode according to claim 5, characterized in that The catalytic material layer further includes sulfur and oxygen, and the mass fraction of the sulfur is 0-0.5%, and the mass fraction of the oxygen is 0-1%.

7. The catalytic electrode according to claim 5, characterized in that In the catalytic material layer, the mass ratio of nickel element, cobalt element and phosphorus element is (6-7):(3-3.5):

1.

8. The catalytic electrode according to claim 1, characterized in that The conductive substrate is made of nickel; and / or The conductive substrate includes one or more of a nickel mesh, a nickel foam, a nickel sheet, a nickel block, and a nickel strip.

9. A method for preparing a catalytic electrode for producing hydrogen by electrolysis of water, characterized in that: include: Placing the conductive substrate as a cathode in an electrodeposition solution for electrodeposition treatment; wherein the electrodeposition solution comprises a nickel source, a cobalt source and a phosphorus source; The conductive substrate after the electrodeposition treatment is subjected to acid washing treatment to obtain a catalytic electrode for hydrogen production by electrolysis of water.

10. The preparation method according to claim 9, characterized in that: The molar concentration of the nickel source is 0.7-0.9 mol / L, the molar concentration of the cobalt source is 0.17-0.23 mol / L, and the molar concentration of the phosphorus source is 0.48-0.72 mol / L.

11. The preparation method according to claim 9, characterized in that: The nickel source comprises one or more of nickel sulfate, nickel chloride, nickel acetate, and nickel sulfamate; and / or The cobalt source includes one or more of cobalt sulfate, cobalt chloride, cobalt acetate, and cobalt nitrate; and / or The phosphorus source includes one or more of sodium hypophosphite and phosphoric acid.

12. The preparation method according to claim 9, characterized in that: The electrodeposition solution further comprises a complexing agent and an electrodeposition additive; and / or The molar concentration of the complexing agent is 0.1-0.16 mol / L, and the molar concentration of the electrodeposition additive is 0.0017-0.008 mol / L.

13. The preparation method according to claim 12, characterized in that: The complexing agent includes one or more of sodium citrate and sodium acetate; and / or The electrodeposition additives include one or more of saccharin and sodium dodecyl sulfate.

14. The preparation method according to claim 9, characterized in that: The pH of the electrodeposition solution is 2-3.

15. The preparation method according to claim 9, characterized in that: During the electrodeposition process, the applied current density is 100-500 mA / cm 2 The power-on time is 3 to 12 minutes.

16. The preparation method according to claim 9, characterized in that: In the pickling treatment, the acid solution used is sulfuric acid.

17. The preparation method according to claim 16, characterized in that: In the pickling treatment, the mass concentration of the sulfuric acid is 20% to 30%, and the pickling time is 10 to 30 seconds.

18. An electrolytic cell, characterized in that: It comprises the catalytic electrode as claimed in any one of claims 1 to 8.

19. A system for producing hydrogen by electrolysis of water, characterized in that: Comprising the electrolytic cell of claim 18.

Images