Porous electrode material and preparation method therefor, and electrolysis device

Abstract

Provided in the present invention are a porous electrode material and a preparation method therefor, and an electrolysis device. The preparation method comprises: printing a grid-shaped high-entropy alloy of a first preset size from a high-entropy alloy powder by means of a selective laser melting process, wherein the composition of the high-entropy alloy powder is NiaFebCocCrdAle; and subjecting the grid-shaped high-entropy alloy to an electrochemical corrosion treatment by using a corrosive liquid so as to allow the surface of the grid-shaped high-entropy alloy to have pores, thereby obtaining a porous electrode material. In the present invention, the high-entropy alloy is first prepared into a grid shape and is then subjected to an electrochemical corrosion treatment, thereby greatly increasing the area of contact between same and the corrosive liquid, improving the porosity, and further enhancing the catalytic effect.

Description

Porous electrode material, preparation method thereof, and electrolysis device Technical Field

[0001] The present invention relates to the technical field of electrolytic hydrogen production, and in particular to a porous electrode material, a preparation method thereof, and an electrolysis device. Background Art

[0002] Water electrolysis is an important technology for converting water into hydrogen and oxygen. It can use renewable energy sources such as solar energy and wind energy to produce hydrogen, thereby achieving sustainable energy development. Effective catalysts can improve the efficiency of water electrolysis and the rate of hydrogen production, reduce costs, and thus promote the development of renewable energy. Traditional water electrolysis catalysts, such as precious metals such as platinum and palladium, are expensive, which not only increases production costs but also has an impact on the environment. In addition, water electrolysis catalysts can also be used to generate and store electricity, and are therefore crucial to the development of energy conversion and storage technologies. Therefore, the development of low-cost and high-efficiency water electrolysis catalysts is of great significance. It can promote the development of sustainable energy, promote the popularization of clean energy vehicles, promote the development of energy conversion and storage technologies, and achieve sustainable energy development.

[0003] Although researchers have developed many transition metal water electrolysis catalysts, there are still many problems, such as:

[0004] 1. Powdered catalysts have poor stability. During long-term water decomposition reactions, the catalysts are prone to deactivation, falling off, or premature wear, resulting in decreased gas production efficiency. Frequent catalyst replacement is required, reducing economic benefits.

[0005] 2. Low selectivity: Some transition metal water electrolysis catalysts may produce unwanted side reactions or products during the water splitting reaction, thereby reducing hydrogen production efficiency. Furthermore, currently commercial nickel foam catalysts have a slow gas production rate, requiring a higher current density to achieve the same hydrogen production, resulting in higher energy costs.

[0006] Therefore, inventing a porous electrode material that can improve hydrogen production efficiency is a technical problem that needs to be solved urgently.

[0007] Summary of the Invention

[0008] In view of this, the present invention aims to solve the technical problem of low hydrogen production efficiency of existing catalyst electrodes.

[0009] A first aspect of the present invention provides a method for preparing a porous electrode material.

[0010] A second aspect of the present invention provides a porous electrode material.

[0011] A third aspect of the present invention provides an application of a porous electrode material.

[0012] A fourth aspect of the present invention provides a catalyst electrode.

[0013] A fifth aspect of the present invention provides an electrolysis device.

[0014] Specifically, the present invention is achieved through the following technical solutions:

[0015] The first aspect of the present invention provides a method for preparing a porous electrode material, comprising the following steps: printing a high entropy alloy powder into a grid-shaped high entropy alloy of a first preset size by a selective laser melting process, wherein the composition of the high entropy alloy powder is Ni a Fe b Co c Cr d Al e , 30≤a≤37, 5≤b≤16.7, 5≤c≤16.7, 5≤d≤16.7, 5≤e≤16.7, a+b+c+d+e=100;

[0016] Electrochemically corroding the grid-shaped high entropy alloy with a corrosive solution to provide pores on the surface of the grid-shaped high entropy alloy, thereby obtaining a porous electrode material;

[0017] The etching solution includes an acid solution and ferrous sulfate, the acid solution includes hydrogen chloride; the molar ratio of the hydrogen chloride to the ferrous sulfate is greater than or equal to 2:1 and less than or equal to 6:1; the concentration of the hydrogen chloride is greater than or equal to 1 mol / L and less than or equal to 3 mol / L; the concentration of the ferrous sulfate is greater than or equal to 0.3 mol / L and less than or equal to 0.8 mol / L.

[0018] The preparation method of the porous electrode material provided by the present invention is to first print a grid-shaped high entropy alloy from high entropy alloy powder through a selective laser melting process, and then electrochemically corrode the grid-shaped high entropy alloy through a corrosive liquid to obtain a grid-shaped porous electrode material. The grid-shaped porous electrode prepared by the present invention has pores on the grid-shaped surface, which increases the active area of ​​the electrode material, exposes more catalytic active sites, improves the porosity of the catalyst electrode, and thus improves the catalytic effect. It can be understood that the current electrode materials are usually electrochemically corroded by the entire bulk, which makes the corrosion area limited and the porosity low. The present invention first prepares the high entropy alloy into a grid shape, and then performs electrochemical corrosion treatment, which greatly increases the contact area with the corrosive liquid, increases the porosity, and thus improves the catalytic effect. In addition, the porous electrode material of the present invention effectively combines the selective laser melting process in the preparation process, thus overcoming the problem of low porosity caused by conventional electrochemical corrosion of large-scale alloys.

[0019] In this technical solution, an acid solution and a mixture of ferrous sulfate are selected as the corrosive solution. Compared with the mixture of acid solution and chromium trioxide, it has a better corrosion effect, which can make the porous electrode material have better alkali resistance and conductivity. Hydrogen chloride has a better pore-forming effect than other acid solutions. Controlling the molar ratio of hydrogen chloride and ferrous sulfate can maximize the corrosion effect and improve the alkali resistance. Controlling the concentration of hydrogen chloride can ensure the optimal pH value of the corrosive solution. Excessive concentration causes the pH value of the corrosive solution to be too large, which is not conducive to pore formation and will affect the alkali resistance of the porous electrode material. The concentration of ferrous sulfate is greater than or equal to 0.3 mol / L and less than or equal to 0.8 mol / L, for example, 0.5 mol / L, which can ensure the pore-forming effect and avoid the problem of excessive ferrous sulfate and insignificant improvement in the pore effect, resulting in waste of materials.

[0020] In the above technical solution, preferably, the pore diameter is greater than or equal to 150 μm and less than or equal to 1000 μm.

[0021] In the above technical solution, the mesh size of the mesh-shaped high entropy alloy is greater than or equal to 200 μm and less than or equal to 800 μm; and / or

[0022] The porous electrode material has a current density of 10 mA / cm in the electrocatalytic oxygen production test. 2 The overpotential is less than or equal to 285mV.

[0023] In the above technical solution, the mesh size of the mesh-shaped high entropy alloy is greater than or equal to 200 μm and less than or equal to 800 μm.

[0024] In this technical solution, the mesh size of the mesh-shaped high-entropy alloy is limited. This can avoid the mesh size being too small, which increases the difficulty of preparing the mesh, and can also avoid the mesh size being too large, which reduces the porosity.

[0025] In the above technical solution, the particle size of the high entropy alloy powder is greater than or equal to 15 μm and less than or equal to 45 μm.

[0026] In this technical solution, controlling the particle size of the high-entropy alloy powder can accelerate the melting rate of the high-entropy alloy powder and increase the printing rate.

[0027] In the above technical solution, the step of printing a grid-shaped high-entropy alloy of a first preset size from high-entropy alloy powder through a selective laser melting process includes: drawing a grid-shaped structure model; importing the grid-shaped structure model into a laser 3D metal printing device, and printing it through the laser 3D metal printing device to obtain a grid-shaped high-entropy alloy of a first preset size.

[0028] In this technical solution, during the printing process of high entropy alloy powder, a grid structure model can be drawn first, the grid structure model can be imported into the laser 3D metal printing device, and then printed by the laser 3D metal printing device to obtain a grid-shaped high entropy alloy.

[0029] In the above technical solution, the length of the first preset dimension is greater than or equal to 40 mm and less than or equal to 60 mm; the width of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm; the height of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm.

[0030] In this technical solution, the length of the first preset dimension is greater than or equal to 40 mm and less than or equal to 60 mm; the width of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm; and the height of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm. Furthermore, the length, width, and height of the first preset dimension are 50 mm × 20 mm × 20 mm, respectively. That is, during the printing process, the size of the printed grid-shaped high-entropy alloy is 50 mm × 20 mm × 20 mm. Controlling the size of the grid-shaped high-entropy alloy can, on the one hand, avoid the problem of too small a size leading to slow printing efficiency, and on the other hand, avoid the problem of too large a size leading to poor later corrosion effect.

[0031] In the above technical solution, after the step of printing high entropy alloy powder into a grid-shaped high entropy alloy of a first preset size through a selective laser melting process, it also includes: cutting the grid-shaped high entropy alloy of the first preset size to cut the grid-shaped high entropy alloy to a second preset size.

[0032] In this technical solution, after printing out the grid-shaped high-entropy alloy, the grid-shaped high-entropy alloy is sawed, which can increase the surface area of ​​the grid-shaped high-entropy alloy, and then increase the contact area with the corrosive liquid during the electrochemical corrosion process, thereby improving the pore formation rate.

[0033] In the above technical solution, the length of the second preset dimension is greater than or equal to 0.5 mm and less than or equal to 1 mm; the width of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm; the height of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm.

[0034] In this technical solution, the length of the second preset size is greater than or equal to 0.5 mm and less than or equal to 1 mm; the width of the second preset size is greater than or equal to 5 mm and less than or equal to 15 mm; the height of the second preset size is greater than or equal to 5 mm and less than or equal to 15 mm. Furthermore, the length, width and height of the second preset size are 0.8 mm × 10 mm × 10 mm, that is, the grid-shaped high entropy alloy is cut to a size of 0.8 mm × 10 mm × 10 mm, which can improve the later pore-forming rate.

[0035] In the above technical solution, in the electrochemical corrosion treatment step, the electrochemical corrosion treatment conditions include: direct current, power-on current greater than or equal to 1.5V and less than or equal to 2V, and power-on time greater than or equal to 1 minute and less than or equal to 5 minutes.

[0036] In this technical solution, electrochemical corrosion is carried out by direct current. Furthermore, the current is greater than or equal to 1.5V and less than or equal to 2V, for example, the current is 1.8V, and the power-on time is greater than or equal to 1 minute and less than or equal to 5 minutes, for example, 3 minutes. By controlling the current and the power-on time, the pore-forming effect can be improved while improving the energy utilization rate and avoiding energy waste.

[0037] In the above technical solution, during the printing process, the printing environment of the laser 3D metal printing equipment is an argon environment.

[0038] In this technical solution, the printing environment of the laser 3D metal printing equipment is an argon environment, which can ensure a safe printing environment.

[0039] In the above technical solution, during the printing process, the diameter of the focused laser beam of the laser 3D metal printing device is greater than or equal to 70 μm and less than or equal to 120 μm.

[0040] In this technical solution, the diameter of the focused laser beam of the laser 3D metal printing device is greater than or equal to 70μm and less than or equal to 120μm. Furthermore, the diameter of the focused laser beam of the laser 3D metal printing device is 90μm, which can ensure printing speed and pore precision, thereby improving the catalytic effect of the porous electrode material.

[0041] In the above technical solution, the laser power of the laser 3D metal printing equipment is greater than or equal to 300W and less than or equal to 500W.

[0042] In this technical solution, the laser power of the laser 3D metal printing device is greater than or equal to 300 W and less than or equal to 500 W. Furthermore, the laser power of the laser 3D metal printing device is 400 W. By controlling the laser power of the laser 3D metal printing device, the printing speed can be guaranteed, the pore accuracy can be ensured, and the catalytic effect of the porous electrode material can be improved.

[0043] In the above technical solution, during the printing process, the scanning speed of the laser of the laser 3D metal printing device is greater than or equal to 1000 mm / s and less than or equal to 1400 mm / s.

[0044] In this technical solution, during the printing process, the laser scanning speed of the laser 3D metal printing device is greater than or equal to 1000 mm / s and less than or equal to 1400 mm / s. Furthermore, the laser scanning speed of the laser 3D metal printing device is 1200 mm / s. By controlling the laser scanning speed of the laser 3D metal printing device, the printing rate can be guaranteed on the one hand, and the quality of the porous electrode material can be guaranteed on the other hand, avoiding excessive printing speed that may affect the catalytic effect of the porous electrode material.

[0045] In the above technical solution, the scanning pitch of the laser of the laser 3D metal printing device is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

[0046] In this technical solution, the laser scanning pitch of the laser 3D metal printing device is greater than or equal to 0.05mm and less than or equal to 0.15mm. Furthermore, the laser scanning pitch of the laser 3D metal printing device is equal to 0.09mm. Controlling the laser scanning pitch of the laser 3D metal printing device can ensure the quality of the porous electrode material and improve the catalytic effect.

[0047] In the above technical solution, the thickness of each layer printed by the laser 3D metal printing device is greater than or equal to 20 μm and less than or equal to 40 μm.

[0048] In this technical solution, the thickness of each layer printed by the laser 3D metal printing device is greater than or equal to 20μm and less than or equal to 40μm. Furthermore, the thickness of each layer printed by the laser 3D metal printing device is 30μm. Controlling the thickness of each layer printed by the laser 3D metal printing device can ensure the quality of the porous electrode material and improve the catalytic effect.

[0049] The second aspect of the present invention provides a porous electrode material obtained by any one of the above preparation methods.

[0050] The porous electrode material provided by the present invention adopts five elements of Ni, Fe, Co, Cr and Al as raw materials of catalyst electrode, so that the prepared porous electrode material has excellent electrolysis of water and oxygen production activity and stability in alkaline medium. In addition, the porous electrode of the present invention is a grid structure, and has pores on the grid surface, so that the active area of ​​the electrode material is increased, more catalytic active sites are exposed, the porosity of the catalyst electrode is increased, and the catalytic effect is improved. It is understandable that current electrode materials are usually subjected to electrochemical corrosion treatment of the entire bulk, so that the corrosion area is limited and the porosity is low, and the present invention first prepares the high entropy alloy into a grid shape, and then carries out electrochemical corrosion treatment, so that the contact area with the corrosive liquid is greatly increased, the porosity is increased, and the catalytic effect is improved.

[0051] In the above technical solution, the porous electrode material has a current density of 10 mA / cm in the electrocatalytic oxygen production test. 2 The overpotential is less than or equal to 285 mV, which makes the porous electrode material of the present invention have good conductivity.

[0052] In the above technical solution, preferably, a=34.4, b=16.4, c=16.4, d=16.4, and e=16.4.

[0053] In this technical solution, a=34.4, b=16.4, c=16.4, d=16.4, e=16.4, that is, the composition of the porous electrode material is Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 By controlling the ratio of five elements, Ni, Fe, Co, Cr and Al, the stability, conductivity and catalytic effect of the porous electrode material in alkaline medium can be maximized.

[0054] In the above technical solution, preferably, the crystal structure of the grid-shaped high entropy alloy includes a face-centered cubic lattice and a body-centered cubic lattice. The high entropy alloy with a face-centered cubic lattice or a body-centered cubic lattice has a higher active area, thereby making the catalytic efficiency higher.

[0055] The technical solution of the third aspect of the present invention provides the use of the porous electrode material of the technical solution of the second aspect of the present invention in the electrolysis of water to produce hydrogen and / or oxygen.

[0056] The technical solution of the fourth aspect of the present invention provides a catalyst electrode, which is prepared by the porous electrode material according to any technical solution of the second aspect of the present invention.

[0057] The technical solution of the fifth aspect of the present invention provides an electrolysis device, comprising the catalyst electrode of the technical solution of the fourth aspect of the present invention.

[0058] Beneficial effect: The porous electrode material provided by the present invention has excellent electrolytic water oxygen production activity and stability in alkaline medium. ‐2 The required overpotential is 270mV to 280mV and can be achieved at 500mA·cm ‐2 It can work continuously for 1000 hours under high temperature and its performance is better than nickel foam. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0061] FIG1 is a schematic flow chart of a method for preparing a porous electrode material according to Example 1 of the present invention;

[0062] FIG2 is a schematic flow chart of a method for preparing a porous electrode material according to Example 2 of the present invention;

[0063] FIG3 is a schematic flow chart of a method for preparing a porous electrode material according to Example 3 of the present invention;

[0064] FIG4 is a schematic flow chart of a method for preparing a porous electrode material according to Example 4 of the present invention;

[0065] FIG5 is a schematic flow chart of a method for preparing a porous electrode material according to Comparative Example 1 of the present invention;

[0066] FIG6 is a schematic flow chart of a method for preparing a porous electrode material according to Comparative Example 2 of the present invention;

[0067] FIG7 is a linear voltammetric sweep curve diagram of hydrogen evolution and oxygen evolution in electrochemical testing of the porous electrode material provided in Example 1 of the present invention;

[0068] FIG8 is a linear voltammetric sweep curve diagram of hydrogen evolution and oxygen evolution in electrochemical testing of the porous electrode material provided in Example 2 of the present invention;

[0069] FIG9 is a linear voltammetric sweep curve diagram of hydrogen evolution and oxygen evolution in electrochemical testing of the porous electrode material provided in Example 3 of the present invention;

[0070] FIG10 is a scanning electron microscope image of a porous electrode material prepared by the method for preparing a porous electrode material provided in Example 1 of the present invention;

[0071] FIG11 is a scanning electron microscope image of a porous electrode material prepared by the method for preparing a porous electrode material provided in Example 2 of the present invention;

[0072] FIG12 is a scanning electron microscope image of a porous electrode material prepared by the method for preparing a porous electrode material provided in Example 3 of the present invention;

[0073] FIG13 is a schematic block diagram of an electrolysis device provided in an embodiment of the present invention.

[0074] The corresponding relationship between the names and numbers of the components in FIG13 is as follows: 1. electrolysis device, 12. catalyst electrode. DETAILED DESCRIPTION

[0075] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0076] An embodiment of the first aspect of the present invention provides a method for preparing a porous electrode material.

[0077] Example 1

[0078] Referring to FIG1 , this embodiment provides a method for preparing a porous electrode material, comprising the following steps:

[0079] S102: Draw a grid structure model;

[0080] S104: The grid structure model is imported into the laser 3D metal printing device, and the high entropy alloy powder (composition Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 ) to obtain a large block of porous electrode material; wherein the diameter of the focused laser beam is equal to 70 μm, the laser power is equal to 300 W, the laser scanning speed is equal to 1000 mm / s, the laser scanning pitch is equal to 0.05 mm, and the thickness of each printed layer is equal to 20 μm;

[0081] S106: cutting the large block of porous electrode material to obtain small blocks of porous electrode material of 0.8 mm×10 mm×10 mm;

[0082] S108: Electrochemically corroding a small piece of the porous electrode material using hydrogen chloride and ferrous sulfate corrosive solutions to obtain a porous electrode material; wherein the molar ratio of hydrogen chloride to ferrous sulfate is 2:1, the concentration of hydrogen chloride is 1 mol / L, the concentration of ferrous sulfate is 0.3 mol / L, the current under direct current is 1.5 V, and the power-on time is 1 minute.

[0083] The scanning electron microscope image of the porous electrode material prepared in this embodiment is shown in FIG10 . The electrochemical performance test of the porous electrode material prepared in this embodiment is carried out. The specific test steps are as follows:

[0084] Silicone rubber was used to seal the non-electrochemical test portion of the porous electrode material prepared in this embodiment, exposing a fixed area of ​​free surface for electrochemical testing. The electrocatalytic material was tested using a linear voltammetric sweep test method. The test used a three-electrode system, with the porous electrode material prepared in this embodiment as the working electrode, mercury / mercuric oxide as the reference electrode, platinum as the auxiliary electrode, and 1 mol / L potassium hydroxide solution as the electrolyte. The hydrogen evolution polarization curve obtained is shown in FIG7 . FIG7 shows that when the current intensity reaches 10 mA / cm 2 When , the hydrogen evolution overpotential is 259 mV. This shows that the porous electrode material in this embodiment has excellent hydrogen evolution catalytic activity.

[0085] Example 2

[0086] 2 , this embodiment provides a method for preparing a porous electrode material, comprising the following steps:

[0087] S202: drawing a grid structure model;

[0088] S204: The grid structure model is imported into the laser 3D metal printing device, and the high entropy alloy powder (composition Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 ) to obtain a large block of porous electrode material; wherein the diameter of the focused laser beam is equal to 120 μm, the laser power is equal to 500 W, the laser scanning speed is equal to 1400 mm / s, the laser scanning spacing is equal to 0.15 mm, and the thickness of each printed layer is equal to 40 μm;

[0089] S206: cutting the large block of porous electrode material to obtain small blocks of porous electrode material of 0.8 mm×10 mm×10 mm;

[0090] S208: Electrochemically corroding a small piece of the porous electrode material using a hydrogen chloride and ferrous sulfate etching solution to obtain a porous electrode material; wherein the molar ratio of hydrogen chloride to ferrous sulfate is 6:1, the concentration of hydrogen chloride is 3 mol / L, the concentration of ferrous sulfate is 0.8 mol / L, the current under direct current is 2 V, and the power-on time is 5 minutes.

[0091] The scanning electron microscope image of the porous electrode material prepared in this embodiment is shown in FIG11 , where 500 μm is the scale bar. The electrochemical performance of the porous electrode material prepared in this embodiment was tested, and the specific test steps are as follows:

[0092] Silicone rubber was used to seal the non-electrochemical test portion of the porous electrode material prepared in this embodiment, exposing a fixed area of ​​free surface for electrochemical testing. The electrocatalytic material was tested using a linear voltammetric sweep test method. The test used a three-electrode system, with the porous electrode material prepared in this embodiment as the working electrode, mercury / mercuric oxide as the reference electrode, platinum as the auxiliary electrode, and a 1 mol / L potassium hydroxide solution as the electrolyte. The hydrogen evolution polarization curve obtained is shown in FIG8 , which shows that when the current intensity reaches 10 mA / cm 2 When , the hydrogen evolution overpotential is 273 mV, which indicates that the porous electrode material in this embodiment has excellent hydrogen evolution catalytic activity.

[0093] Example 3

[0094] 3 , this embodiment provides a method for preparing a porous electrode material, comprising the following steps:

[0095] S302: drawing a grid structure model;

[0096] S304: The grid structure model is imported into the laser 3D metal printing device, and the high entropy alloy powder (composed of Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 ) to obtain a large block of porous electrode material; wherein the diameter of the focused laser beam is equal to 90 μm, the laser power is equal to 400 W, the laser scanning speed is equal to 1200 mm / s, the laser scanning pitch is equal to 0.1 mm, and the thickness of each printed layer is equal to 30 μm;

[0097] S306: cutting the large block of porous electrode material to obtain small blocks of porous electrode material of 0.8 mm×10 mm×10 mm;

[0098] S308: Electrochemically corroding a small piece of the porous electrode material using a hydrogen chloride and ferrous sulfate corrosive solution to obtain a porous electrode material; wherein the molar ratio of hydrogen chloride to ferrous sulfate is 4:1, the concentration of hydrogen chloride is 2 mol / L, the concentration of ferrous sulfate is 0.5 mol / L, the current under direct current is 1.8 V, and the power-on time is 3 minutes.

[0099] The scanning electron microscope image of the porous electrode material prepared in this embodiment is shown in FIG12 . The electrochemical performance test of the porous electrode material prepared in this embodiment is carried out. The specific test steps are as follows:

[0100] Silicone rubber was used to seal the non-electrochemical test portion of the porous electrode material prepared in this embodiment, exposing a fixed area of ​​free surface for electrochemical testing. The electrocatalytic material was tested using a linear voltammetric sweep test method. The test used a three-electrode system, with the porous electrode material prepared in this embodiment as the working electrode, mercury / mercuric oxide as the reference electrode, and platinum as the auxiliary electrode. The electrolyte used was a 1 mol / L potassium hydroxide solution. The hydrogen evolution polarization curve obtained is shown in FIG9 , which shows that when the current intensity reaches 10 mA / cm 2 When , the hydrogen evolution overpotential is 283 mV. This shows that the porous electrode material in this embodiment has excellent hydrogen evolution catalytic activity.

[0101] Example 4

[0102] 4 , this embodiment provides a method for preparing a porous electrode material, comprising the following steps:

[0103] S402: Printing a high entropy alloy powder into a grid-shaped high entropy alloy of a first preset size through a selective laser melting process, wherein the composition of the high entropy alloy powder is Ni a Fe b Co c Cr d Al e , 30≤a≤37, 5≤b≤16.7, 5≤c≤16.7, 5≤d≤16.7, 5≤e≤16.7, a+b+c+d+e=100;

[0104] S404: electrochemically corroding the grid-shaped high entropy alloy using a corrosive solution to obtain a porous electrode material;

[0105] The present invention provides a method for preparing a porous electrode material. First, a grid-shaped high-entropy alloy is printed from high-entropy alloy powder through a selective laser melting process. Specifically, a grid-shaped molded part data model with pores of not less than 200 microns is first drawn using CAD drawing software, and the output file format is STL. The data model is imported into an SLM device for printing. A grid-shaped NiFeCoCrAl high-entropy alloy with a pore size of 200μm to 800μm is printed at room temperature. The crystal structure is mainly composed of FCC phase and BCC phase. Then, the grid-shaped high-entropy alloy is electrochemically corroded by a corrosive solution to obtain a grid-shaped porous electrode material. The grid-shaped porous electrode prepared by the present invention has pores on the grid-shaped surface, which increases the active area of ​​the electrode material, exposes more catalytic active sites, improves the porosity of the catalyst electrode, and thus improves the catalytic effect. Understandably, current electrode materials typically undergo electrochemical corrosion of the entire bulk, which results in a limited corrosion area and low porosity. However, the present invention first prepares the high-entropy alloy into a grid-like shape before subjecting it to electrochemical corrosion. This significantly increases the contact area with the corrosive fluid, increases the porosity, and thus enhances the catalytic effect. Furthermore, the porous electrode material of the present invention effectively incorporates a selective laser melting process during its preparation, thus overcoming the problem of low porosity caused by conventional electrochemical corrosion of bulk alloys.

[0106] In the above embodiment, the mesh size of the mesh-shaped high entropy alloy is greater than or equal to 200 μm and less than or equal to 800 μm.

[0107] In this embodiment, the mesh size of the mesh-shaped high entropy alloy is limited. This can avoid the mesh size being too small, which increases the difficulty of preparing the mesh, and can also avoid the mesh size being too large, which reduces the porosity.

[0108] In the above embodiment, the particle size of the high entropy alloy powder is greater than or equal to 15 μm and less than or equal to 45 μm.

[0109] In this embodiment, controlling the particle size of the high entropy alloy powder can accelerate the melting rate of the high entropy alloy powder and increase the printing rate.

[0110] In the above embodiment, the step of printing a grid-shaped high-entropy alloy of a first preset size from high-entropy alloy powder through a selective laser melting process includes: drawing a grid-shaped structure model; importing the grid-shaped structure model into a laser 3D metal printing device, and printing it through the laser 3D metal printing device to obtain a grid-shaped high-entropy alloy of a first preset size.

[0111] In this embodiment, during the printing process of high entropy alloy powder, a grid structure model can be drawn first, the grid structure model can be imported into the laser 3D metal printing device, and then printed by the laser 3D metal printing device to obtain a grid-shaped high entropy alloy.

[0112] In the above embodiment, the length of the first preset dimension is greater than or equal to 40 mm and less than or equal to 60 mm; the width of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm; the height of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm.

[0113] In this embodiment, the length of the first preset dimension is greater than or equal to 40 mm and less than or equal to 60 mm; the width of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm; and the height of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm. Furthermore, the length, width, and height of the first preset dimension are 50 mm × 20 mm × 20 mm, respectively. That is, during the printing process, the size of the printed grid-shaped high-entropy alloy is 50 mm × 20 mm × 20 mm. Controlling the size of the grid-shaped high-entropy alloy can, on the one hand, avoid the problem of too small a size leading to slow printing efficiency, and on the other hand, avoid the problem of too large a size leading to poor later corrosion effect.

[0114] In the above embodiment, after the step of printing high entropy alloy powder into a grid-shaped high entropy alloy of a first preset size through a selective laser melting process, it also includes: cutting the grid-shaped high entropy alloy of the first preset size to cut the grid-shaped high entropy alloy to a second preset size.

[0115] In this embodiment, after printing the grid-shaped high-entropy alloy, the grid-shaped high-entropy alloy is sawed, which can increase the surface area of ​​the grid-shaped high-entropy alloy, and then increase the contact area with the corrosive liquid during the electrochemical corrosion process, thereby improving the pore formation rate.

[0116] In the above embodiment, the length of the second preset dimension is greater than or equal to 0.5 mm and less than or equal to 1 mm; the width of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm; and the height of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm.

[0117] In this embodiment, the length of the second preset dimension is greater than or equal to 0.5 mm and less than or equal to 1 mm; the width of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm; the height of the second preset dimension is greater than or equal to 5 mm and less than or equal to 15 mm. Furthermore, the length, width and height of the second preset dimension are 0.8 mm × 10 mm × 10 mm, that is, the grid-shaped high entropy alloy is cut to a size of 0.8 mm × 10 mm × 10 mm, which can improve the later pore-forming rate.

[0118] In the above embodiment, the etching solution includes an acid solution and ferrous sulfate.

[0119] In this embodiment, a mixture of hydrogen chloride and ferrous sulfate is selected as the etching solution, which has a better etching effect than a mixture of hydrogen chloride and chromium trioxide, and can make the porous electrode material have better alkali resistance and stability.

[0120] In the above embodiment, the acid solution includes hydrogen chloride.

[0121] In the above embodiment, the molar ratio of hydrogen chloride to ferrous sulfate is greater than or equal to 2:1 and less than or equal to 6:1.

[0122] In this embodiment, controlling the molar ratio of hydrogen chloride to ferrous sulfate can maximize the corrosion effect and improve the alkali resistance stability.

[0123] In the above embodiment, the concentration of hydrogen chloride is greater than or equal to 1 mol / L and less than or equal to 3 mol / L.

[0124] In this embodiment, controlling the concentration of hydrogen chloride can ensure the optimal pH value of the etching solution. Excessive concentration will result in an excessively high pH value of the etching solution, which is not conducive to pore formation and will affect the alkali resistance stability of the porous electrode material.

[0125] In the above embodiment, the concentration of ferrous sulfate is greater than or equal to 0.3 mol / L and less than or equal to 0.8 mol / L.

[0126] In this embodiment, the concentration of ferrous sulfate is greater than or equal to 0.3 mol / L and less than or equal to 0.8 mol / L, for example, 0.5 mol / L. This can ensure the pore-forming effect and avoid the problem of excessive ferrous sulfate and insignificant improvement in the porosity, resulting in waste of materials.

[0127] In the above embodiment, in the electrochemical corrosion treatment step, the electrochemical corrosion treatment conditions include: direct current, power-on current greater than or equal to 1.5V and less than or equal to 2V, and power-on time greater than or equal to 1 minute and less than or equal to 5 minutes.

[0128] In this embodiment, electrochemical corrosion is performed by direct current. Furthermore, the current is greater than or equal to 1.5V and less than or equal to 2V, for example, the current is 1.8V, and the power-on time is greater than or equal to 1 minute and less than or equal to 5 minutes, for example, 3 minutes. By controlling the current and the power-on time, the pore-forming effect can be improved while improving the energy utilization rate and avoiding energy waste.

[0129] In the above embodiment, during the printing process, the printing environment of the laser 3D metal printing device is an argon environment.

[0130] In this embodiment, the printing environment of the laser 3D metal printing device is an argon environment, preferably high-purity argon, which can ensure a safe printing environment.

[0131] In the above embodiment, during the printing process, the diameter of the focused laser beam of the laser 3D metal printing device is greater than or equal to 70 μm and less than or equal to 120 μm.

[0132] In this embodiment, the diameter of the focused laser beam of the laser 3D metal printing device is greater than or equal to 70 μm and less than or equal to 120 μm. Furthermore, the diameter of the focused laser beam of the laser 3D metal printing device is 90 μm, which can ensure printing speed and pore precision, thereby improving the catalytic effect of the porous electrode material.

[0133] In the above embodiment, the laser power of the laser 3D metal printing device is greater than or equal to 300W and less than or equal to 500W.

[0134] In this embodiment, the laser power of the laser 3D metal printing device is greater than or equal to 300 W and less than or equal to 500 W. Furthermore, the laser power of the laser 3D metal printing device is 400 W. By controlling the laser power of the laser 3D metal printing device, the printing speed can be guaranteed, the accuracy of the pores can be ensured, and the catalytic effect of the porous electrode material can be improved.

[0135] In the above embodiment, during the printing process, the scanning speed of the laser of the laser 3D metal printing device is greater than or equal to 1000 mm / s and less than or equal to 1400 mm / s.

[0136] In this embodiment, during the printing process, the laser scanning speed of the laser 3D metal printing device is greater than or equal to 1000 mm / s and less than or equal to 1400 mm / s. Furthermore, the laser scanning speed of the laser 3D metal printing device is 1200 mm / s. By controlling the laser scanning speed of the laser 3D metal printing device, the printing rate can be guaranteed on the one hand, and the quality of the porous electrode material can be guaranteed on the other hand, avoiding excessive printing speed that may affect the catalytic effect of the porous electrode material.

[0137] In the above embodiment, the scanning pitch of the laser of the laser 3D metal printing device is greater than or equal to 0.05 mm and less than or equal to 0.15 mm.

[0138] In this embodiment, the laser scanning pitch of the laser 3D metal printing device is greater than or equal to 0.05 mm and less than or equal to 0.15 mm. Furthermore, the laser scanning pitch of the laser 3D metal printing device is equal to 0.09 mm. Controlling the laser scanning pitch of the laser 3D metal printing device can ensure the quality of the porous electrode material and improve the catalytic effect.

[0139] In the above embodiment, the thickness of each layer printed by the laser 3D metal printing device is greater than or equal to 20 μm and less than or equal to 40 μm.

[0140] In this embodiment, the thickness of each layer printed by the laser 3D metal printing device is greater than or equal to 20 μm and less than or equal to 40 μm. Furthermore, the thickness of each layer printed by the laser 3D metal printing device is 30 μm. Controlling the thickness of each layer printed by the laser 3D metal printing device can ensure the quality of the porous electrode material and improve the catalytic effect.

[0141] Comparative Example 1

[0142] Referring to FIG5 , this comparative example provides a method for preparing an electrode material, comprising the following steps:

[0143] S502: drawing a grid structure model;

[0144] S504: The grid structure model is imported into the laser 3D metal printing device, and the high entropy alloy powder (composition Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 ) to obtain a large block of porous electrode material; wherein the diameter of the focused laser beam is equal to 90 μm, the laser power is equal to 400 W, the laser scanning speed is equal to 1200 mm / s, the laser scanning pitch is equal to 0.1 mm, and the thickness of each printed layer is equal to 30 μm;

[0145] S506: Cutting the large block of porous electrode material to obtain small blocks of porous electrode material of 0.8 mm×10 mm×10 mm as porous electrode material.

[0146] The electrochemical performance of the porous electrode material prepared in this comparative example was tested. The specific test steps were the same as those in each of the above examples. The results showed that when the current intensity reached 10 mA / cm 2 When the hydrogen evolution overpotential is 353 mV, it shows that the porous electrode material in this comparative example has poor hydrogen evolution catalytic activity. This is because it is not corroded by the corrosive liquid, so that a large number of pores are not generated on the surface of the prepared electrode material, which makes the conductivity low.

[0147] Comparative Example 2

[0148] Referring to FIG6 , this comparative example provides a method for preparing a porous electrode material, comprising the following steps:

[0149] S602: The bulk of the high-entropy alloy obtained in S504 in Comparative Example 1 is subjected to electrochemical corrosion treatment using hydrogen chloride and ferrous sulfate etching solutions to obtain a porous electrode material; wherein the molar ratio of hydrogen chloride to ferrous sulfate is equal to 4:1, the concentration of hydrogen chloride is equal to 2 mol / L, the concentration of ferrous sulfate is equal to 0.5 mol / L, the current under direct current is equal to 1.8 V, and the power-on time is equal to 3 minutes.

[0150] The electrochemical performance of the porous electrode material prepared in this comparative example was tested. The specific test steps were the same as those in each of the above examples. The results showed that when the current intensity reached 10 mA / cm 2 When , the hydrogen evolution overpotential is 360 mV, which indicates that the porous electrode material in this comparative example has poor hydrogen evolution catalytic activity. This is because although the large block of the high entropy alloy is corroded by the corrosive liquid, the contact area between the high entropy alloy and the corrosive liquid is small during the corrosion process, which makes the porosity of the prepared porous electrode material low, and thus makes the active area of ​​the electrode material small, the active sites are small, and the conductivity is low.

[0151] An embodiment of the second aspect of the present invention provides a porous electrode material prepared by the method for preparing the porous electrode material of any of the above embodiments.

[0152] The porous electrode material comprises a grid-shaped high entropy alloy, the composition of the high entropy alloy is Ni a Fe b Co c Cr d Al e , 30≤a≤37, 5≤b≤16.7, 5≤c≤16.7, 5≤d≤16.7, 5≤e≤16.7, a+b+c+d+e=100, the grid-like high entropy alloy surface has pores.

[0153] The porous electrode material provided by the present invention adopts five elements of Ni, Fe, Co, Cr and Al as raw materials of catalyst electrode, so that the prepared porous electrode material has excellent electrolysis of water and oxygen production activity and stability in alkaline medium. In addition, the porous electrode of the present invention is a grid structure, and has pores on the grid surface, so that the active area of ​​the electrode material is increased, more catalytic active sites are exposed, the porosity of the catalyst electrode is increased, and the catalytic effect is improved. It is understandable that current electrode materials are usually subjected to electrochemical corrosion treatment of the entire bulk, so that the corrosion area is limited and the porosity is low, and the present invention first prepares the high entropy alloy into a grid shape, and then carries out electrochemical corrosion treatment, so that the contact area with the corrosive liquid is greatly increased, the porosity is increased, and the catalytic effect is improved.

[0154] In the above embodiment, the pore diameter is greater than or equal to 150 μm and less than or equal to 1000 μm.

[0155] In this embodiment, the pore size is limited, which can improve the catalytic activity of the porous electrode material.

[0156] In the above embodiment, the mesh size of the mesh-shaped high entropy alloy is greater than or equal to 200 μm and less than or equal to 800 μm.

[0157] In this embodiment, the mesh size of the mesh-shaped high entropy alloy is limited. This can avoid the mesh size being too small, which increases the difficulty of preparing the mesh, and can also avoid the mesh size being too large, which reduces the porosity.

[0158] In the above embodiment, the porous electrode material is tested for electrocatalytic oxygen production at a current density of 10 mA / cm 2 The overpotential is less than or equal to 285 mV, which makes the porous electrode material of the present invention have good conductivity.

[0159] In the above embodiment, a=34.4, b=16.4, c=16.4, d=16.4, and e=16.4.

[0160] In this embodiment, a=34.4, b=16.4, c=16.4, d=16.4, e=16.4, that is, the composition of the porous electrode material is Ni 34.4 Fe 16.4 Co 16.4 Cr 16.4 Al 16.4 By controlling the ratio of five elements, Ni, Fe, Co, Cr and Al, the stability, conductivity and catalytic effect of the porous electrode material in alkaline medium can be maximized.

[0161] In the above embodiment, the crystal structure of the grid-shaped high entropy alloy includes a face-centered cubic lattice and a body-centered cubic lattice.

[0162] In this embodiment, the high entropy alloy with a face-centered cubic lattice or a body-centered cubic lattice has a higher active area, thereby making the catalytic efficiency higher.

[0163] An embodiment of the third aspect of the present invention provides the use of a porous electrode material in the electrolysis of water to produce hydrogen and / or oxygen. The porous electrode material used is a porous electrode material prepared by the method for preparing a porous electrode material according to any embodiment of the first aspect of the present invention or a porous electrode material according to any embodiment of the second aspect.

[0164] An embodiment of the fourth aspect of the present invention provides a catalyst electrode 12, which is made of a porous electrode material prepared by the method for preparing a porous electrode material according to any embodiment of the first aspect of the present invention.

[0165] 13 , an embodiment of the fifth aspect of the present invention provides an electrolysis device 1 , comprising a catalyst electrode 12 according to the embodiment of the fourth aspect of the present invention.

[0166] Beneficial effect: The porous electrode material provided by the present invention has excellent electrolytic water oxygen production activity and stability in alkaline medium. ‐2 The required overpotential is 270mV to 280mV and can be achieved at 500mA·cm ‐2 It can work continuously for 1000 hours under high temperature and its performance is better than nickel foam.

[0167] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a porous electrode material, characterized in that: The steps include: A high entropy alloy powder is printed into a grid-shaped high entropy alloy of a first preset size by a selective laser melting process, wherein the composition of the high entropy alloy powder is Ni a Fe b Co c Cr d Al e , 30≤a≤37, 5≤b≤16.7, 5≤c≤16.7, 5≤d≤16.7, 5≤e≤16.7, a+b+c+d+e=100; Electrochemically corroding the grid-shaped high entropy alloy with a corrosive solution to provide pores on the surface of the grid-shaped high entropy alloy, thereby obtaining the porous electrode material; The corrosive liquid includes an acid solution and ferrous sulfate, the acid solution includes hydrogen chloride; the molar ratio of the hydrogen chloride to the ferrous sulfate is greater than or equal to 2:1 and less than or equal to 6:1; the concentration of the hydrogen chloride is greater than or equal to 1 mol / L and less than or equal to 3 mol / L; the concentration of the ferrous sulfate is greater than or equal to 0.3 mol / L and less than or equal to 0.8 mol / L.

2. The method for preparing a porous electrode material according to claim 1, characterized in that: The pores have a pore diameter greater than or equal to 150 μm and less than or equal to 1000 μm.

3. The method for preparing a porous electrode material according to claim 1, characterized in that: The mesh size of the mesh-shaped high entropy alloy is greater than or equal to 200 μm and less than or equal to 800 μm; and / or The porous electrode material has a current density of 10 mA / cm in the electrocatalytic oxygen production test. 2 The overpotential is less than or equal to 285mV.

4. The method for preparing a porous electrode material according to claim 1, characterized in that: The particle size of the high entropy alloy powder is greater than or equal to 15 μm and less than or equal to 45 μm.

5. The method for preparing a porous electrode material according to claim 1, characterized in that: The step of printing a grid-shaped high entropy alloy of a first preset size from high entropy alloy powder by a selective laser melting process comprises: Draw a grid-like structure model; The grid structure model is introduced into a laser 3D metal printing device, and is printed by the laser 3D metal printing device to obtain a grid-shaped high-entropy alloy of the first preset size.

6. The method for preparing a porous electrode material according to claim 5, characterized in that: The length of the first preset size is greater than or equal to 40 mm and less than or equal to 60 mm; The width of the first preset size is greater than or equal to 10 mm and less than or equal to 30 mm; The height of the first preset dimension is greater than or equal to 10 mm and less than or equal to 30 mm.

7. The method for preparing a porous electrode material according to claim 1, characterized in that: After the step of printing the high entropy alloy powder into a grid-shaped high entropy alloy of a first preset size by the selective laser melting process, the method further includes: The first preset size grid-shaped high entropy alloy is cut to cut the grid-shaped high entropy alloy into a first preset size grid-shaped high entropy alloy.

2. Preset size.

8. The method for preparing a porous electrode material according to claim 7, characterized in that: The length of the second preset size is greater than or equal to 0.5 mm and less than or equal to 1 mm; The width of the second preset size is greater than or equal to 5 mm and less than or equal to 15 mm; The height of the second preset size is greater than or equal to 5 mm and less than or equal to 15 mm.

9. The method for preparing a porous electrode material according to claim 1, characterized in that: In the step of electrochemical corrosion treatment, the electrochemical corrosion treatment conditions include: direct current, power-on current greater than or equal to 1.5V and less than or equal to 2V, and power-on time greater than or equal to 1 minute and less than or equal to 5 minutes.

10. The method for preparing a porous electrode material according to claim 5, characterized in that: In the step of printing by the laser 3D metal printing device, the printing environment of the laser 3D metal printing device is an argon gas environment; In the step of printing by the laser 3D metal printing device, the diameter of the focused laser beam of the laser 3D metal printing device is greater than or equal to 70 μm and less than or equal to 120 μm; and / or In the step of printing by the laser 3D metal printing device, the laser power of the laser 3D metal printing device is greater than or equal to 300W and less than or equal to 500W; and / or In the step of printing by the laser 3D metal printing device, the scanning speed of the laser of the laser 3D metal printing device is greater than or equal to 1000 mm / s and less than or equal to 1400 mm / s; and / or In the step of printing by the laser 3D metal printing device, the scanning pitch of the laser of the laser 3D metal printing device is greater than or equal to 0.05 mm and less than or equal to 0.15 mm; and / or In the step of printing by the laser 3D metal printing device, the thickness of each layer printed by the laser 3D metal printing device is greater than or equal to 20 μm and less than or equal to 40 μm; and / or In the step of printing by the laser 3D metal printing device, the diameter of the focused laser beam of the laser 3D metal printing device is 90 μm; and / or In the step of printing by the laser 3D metal printing device, the laser power of the laser 3D metal printing device is 400W; and / or In the step of printing by the laser 3D metal printing device, the scanning speed of the laser of the laser 3D metal printing device is 1200 mm / s; and / or In the step of printing by the laser 3D metal printing device, the scanning pitch of the laser of the laser 3D metal printing device is equal to 0.09 mm; In the step of printing by the laser 3D metal printing device, the thickness of each layer printed by the laser 3D metal printing device is 30 μm.

11. A porous electrode material prepared by the method for preparing a porous electrode material according to any one of claims 1 to 10.

12. Use of the porous electrode material according to claim 11 in preparing hydrogen and / or oxygen by electrolysis of water.

13. A catalyst electrode, characterized in that: The catalyst electrode is prepared according to the porous electrode material according to claim 11.

14. An electrolysis device, characterized in that: Comprising the catalyst electrode as claimed in claim 13.

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