CN116575045B - A MEA water splitting device used in water splitting catalysis and its preparation method - Google Patents

Abstract

The application discloses an MEA water splitting device applied to water splitting catalysis and a preparation method thereof, wherein the water splitting device comprises a nickel screen lamination and MEA equipment, and the nickel screen lamination is placed in the MEA equipment; the nickel screen is laminated with 2 layers, one layer is a 60-mesh nickel screen, and the other layer is a 300-mesh nickel screen; the preparation method comprises the following steps: putting a nickel screen into a beaker; pouring pure HCl solution, completely immersing a nickel screen, covering a sealing film, and putting the nickel screen into an ultrasonic cleaner for cleaning until the color of the solution changes from colorless to blue-green; the acid treated web is then washed with water and ethanol to remove any unwanted debris and grease; secondly, completely aligning the two nickel screens after treatment, and then placing the nickel screens into a tablet press to make nickel screen lamination; finally, the nickel mesh stack was placed into an MEA apparatus. Based on the design, the application realizes the technical effect of promoting water decomposition while protecting the anion exchange membrane in the assembly process of the MEA water decomposition device.

Description

A MEA water splitting device used in water splitting catalysis and its preparation method

Technical field

The invention relates to the field of water splitting, and in particular to an MEA water splitting device used in water splitting catalysis and a preparation method thereof.

Background technique

Water splitting catalysts are materials that can promote the water splitting process to produce oxygen and hydrogen. The membrane electrode assembly (MEA) is a key component of many electrochemical devices, and mass transfer limitations are a key factor affecting the performance and efficiency of the MEA water splitting device. This device uses OER catalysts produce hydrogen and oxygen from water. Although existing OER catalysts can promote water splitting well, most of them are rare and expensive elements, such as iridium, platinum and ruthenium, which also makes the production cost of OER catalysts high and limits their application in large areas. Scalability in commercial applications at scale.

Researchers have discovered and synthesized a series of new materials for OER catalysts, such as metal oxides, perovskites, and metal-organic frameworks, which have high catalytic activity, stability, and selectivity and can be modified through doping, surface modification, etc. properties and other methods to further improve its performance.

For example, Chinese patent CN113174600A discloses a porous nickel mesh electrolytic water catalytic material and a preparation method thereof. The preparation method of the porous nickel mesh electrolytic water catalytic material includes the following steps: Step 1. In a two-electrode system, an electrolytic cell is provided with In the electrolyte solution, the pretreated commercial nickel mesh is used as the working electrode, and the platinum sheet is used as the counter electrode. After applying current, the nickel nanoparticle layer is loaded on the commercial nickel mesh using the electrodeposition method to obtain a commercial nickel mesh loaded with nickel nanoparticle layer. ; Step 2. After taking out the commercial nickel mesh loaded with the nickel nanoparticle layer in step 1 from the electrolytic tank, wash and naturally dry to obtain a porous nickel mesh electrolysis water catalytic material. The porous nickel mesh electrolysis water catalytic material prepared by it has high catalytic activity, which can effectively improve the efficiency of water electrolysis, reduce energy consumption, and thus significantly reduce the cost of hydrogen production by electrolysis of water. However, due to the high surface roughness of the nickel mesh, instead Will reduce the mechanical properties of the anion exchange membrane.

Efficient water splitting requires rapid transfer of reactants, products, and electrolyte ions between the various components of the MEA. Mass transfer limitations can lead to poor performance and reduced efficiency of the water splitting process, and the activity and effectiveness of the OER catalyst will also be affected. Limited due to poor mass transfer. For example, if the reactants cannot reach the catalyst surface quickly enough, the OER reaction may not proceed efficiently, resulting in lower hydrogen production rates. Secondly, membrane performance in MEA will also be affected by mass transfer limitations. For example, if reactants and products cannot diffuse through the membrane fast enough, this can harm membrane performance and reduce the efficiency of the water splitting process. Finally, mass transfer limitations can also lead to local concentration gradients and uneven current densities, which can lead to uneven wear of MEA components and ultimately reduce the durability and service life of the equipment.

For example, Chinese patent CN110205636A discloses a method for preparing a self-supporting three-dimensional porous structure bifunctional catalytic electrode. The bifunctional catalytic electrode is prepared by using a nickel mesh as the cathode and an inert conductor as the anode. In an aqueous solution of nickel chloride and ammonium chloride, electrodeposition is performed under normal temperature and pressure conditions to prepare three-dimensional hierarchical porous nickel; thereafter The obtained nickel mesh is used as the cathode for electrodeposition, and an inert conductor is used as the anode. It is immersed in an aqueous solution containing nickel nitrate, ferrous sulfate, and ethylene glycol, and then electrodeposited under normal temperature and pressure conditions to obtain a porous Hierarchical structure of nickel-iron/nickel/nickel catalytic electrode; achieved through two-step electrodeposition to obtain a large effective active area, bubble precipitation channels and excellent conductivity, showing excellent electrochemical hydrogen evolution and oxygen evolution performance under alkaline conditions electrode, but also because the nickel-iron/nickel/nickel catalytic electrode has a porous hierarchical structure, its surface roughness will reduce the mechanical properties of the anion exchange membrane.

Since the surface of the nickel mesh in the existing OER catalyst is rough, it will reduce the mechanical properties of the anion exchange membrane and will not protect the anion exchange membrane during the assembly of the MEA water splitting device. At this time, there is an urgent need to design a new A water splitting device and a preparation method thereof are provided to solve the problem of mass transfer under high current and achieve the effect of protecting anion exchange membranes.

Contents of the invention

Aiming at the problem that the surface of the nickel mesh in the OER catalyst is rough, which in turn leads to reduced mechanical properties of the anion exchange membrane, this application designs a MEA water splitting device and its preparation method for water splitting catalysis, in order to realize the assembly of the MEA water splitting device. During the process, the anion exchange membrane is protected and the effect of promoting water decomposition is achieved.

An MEA water splitting device used in water splitting catalysis, including a nickel mesh stack and MEA equipment, and the nickel mesh stack is placed in the MEA equipment;

The nickel mesh stack includes two layers of nickel mesh with different pores.

Preferably, the nickel mesh stack includes a 60-mesh nickel mesh and a 300-mesh nickel mesh.

Preferably, the length of the two-layer nickel mesh is 0.5~2 cm and the width is 0.5~2 cm.

Preferably, the area of the nickel mesh stack is 1 cm ² .

A preparation method for an MEA water splitting device used in water splitting catalysis, including the following steps:

Step S1: Put the industrial pure nickel mesh with a mesh number of 60 and the industrial pure nickel mesh with a mesh number of 300 into a beaker;

Step S2: Pour the pure HCl solution into the beaker so that the nickel mesh is completely submerged;

Step S3: Cover the beaker with a sealing film to prevent the HCl solution from evaporating or overflowing, and then put it into an ultrasonic cleaner for cleaning until the color of the solution changes from colorless to blue-green;

Step S4: Wash the acid-treated mesh with water and ethanol to remove any unwanted debris and grease;

Step S5: Completely align the two processed nickel meshes, and then put them into a tablet press to make a nickel mesh stack.

Step S6: Place the nickel mesh stack into the MEA equipment.

Preferably, the pure HCl solution in step S2 is a 3 mol HCl solution.

Preferably, in step S3, the cleaning time is 1 to 3 h.

Preferably, in step S5, the applied pressure of the tablet press is 10 MPa.

Preferably, in step S5, the length of the two nickel meshes is 1 cm and the width is 1 cm.

Preferably, a thin film is also provided on the outside of the 300-mesh nickel mesh.

Beneficial effects obtained by the present invention:

1. Due to the unique pointed surface structure of nickel foam, this surface perforation weakens the anion exchange membrane. In the traditional MEA assembly process, the damage of the anion exchange membrane is a very common problem, which seriously reduces the stability of the MEA, thus Hindering the industrialization of water electrolysis using MEA. The MEA water splitting device used in water splitting catalysis designed in this application designs a nickel mesh stack, that is, a double-layer nickel mesh with physical high-pressure treatment. The nickel mesh stack has a smooth plane, which avoids the MEA in the Membrane damage during installation.

2. The invention designs a MEA water splitting device for water splitting catalysis. The membrane|300|60 anode catalyst is selected and placed in the MEA water splitting device. The membrane|300|60 anode catalyst has the best water splitting catalytic performance. .

3. The nickel mesh stack designed in the present invention can also be used as a substrate, and the nickel iron catalyst grown on this can increase the water decomposition performance by changing the mass transfer.

The above description is only an overview of the technical solutions of the present application. In order to have a clearer understanding of the technical means of the present application so that they can be implemented in accordance with the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand. , the preferred embodiments of the present application are described in detail below with reference to the accompanying drawings.

Based on the following detailed description of specific embodiments of the present application in conjunction with the accompanying drawings, those skilled in the art will further understand the above and other objects, advantages and features of the present application.

Description of the drawings

In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are: For some embodiments of the present application, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts. Throughout the drawings, similar elements or portions are generally identified by similar reference numerals. In the drawings, elements or parts are not necessarily drawn to actual scale.

Figure 1 is a side view of the nickel mesh stack provided by this application;

Figure 2 is a comparison chart of the mass transfer effect of the single-mesh nickel mesh provided by this application;

Figure 3 is a front SEM image of the 300 mesh and 60 mesh nickel mesh stack provided by this application;

Figure 4 is the reverse SEM image of the 300 mesh and 60 mesh nickel mesh stack provided by this application;

Figure 5 is a performance comparison chart of different types of nickel mesh provided in this application;

Figure 6 is a comparison chart of the nickel mesh effects of 300 mesh, 60 mesh and combinations thereof provided by this application;

Figure 7 is a distribution time diagram of bubbles generated by different types of nickel mesh provided by this application;

Figure 8 is a comparison chart of literature provided by this application;

Figure 9 is a performance diagram of nickel mesh 300|60 provided by this application under different pressures;

Figure 10 is an SEM picture of the nickel mesh 300|60 provided by this application under different pressures.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments These are part of the embodiments of this application, but not all of them. In the following description, specific details, such as specific configurations and components, are provided solely to assist in a comprehensive understanding of embodiments of the present application. Accordingly, it will be apparent to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the application. In addition, descriptions of well-known functions and constructions are omitted from the embodiments for clarity and conciseness.

It will be understood that reference throughout this specification to "one embodiment" or "the present embodiment" means that a particular feature, structure, or characteristic associated with the embodiment is included in at least one embodiment of the present application. Thus, the appearances of "one embodiment" or "this embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

Furthermore, this application may repeat reference numbers and/or letters in different examples. This repetition is for purposes of simplicity and clarity and does not by itself indicate a relationship between the various embodiments and/or arrangements discussed.

The term "and/or" in this article is just an association relationship that describes related objects, indicating that three relationships can exist. For example, A and/or B can mean: A exists alone, B exists alone, and A and A exist simultaneously. In the three cases of B, the term "/and" in this article describes another associated object relationship, which means that there can be two relationships. For example, A/ and B can mean: A alone exists, and A and B exist alone. , In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

The term "at least one" in this article is just an association relationship that describes associated objects, indicating that there can be three relationships. For example, at least one of A and B can mean: A exists alone, and A and B exist simultaneously. There are three cases of B alone.

It should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that these entities or operations There is no such actual relationship or sequence between them. Furthermore, the terms "includes," "includes," or any other variation thereof are intended to cover a non-exclusive inclusion.

Example 1

Because membrane breakage is a common problem during MEA assembly, the reason is that due to the unique spiky surface structure of nickel foam, this surface perforation weakens the membrane. This reduces the stability of MEA, thereby hindering the industrialization of water electrolysis using MEA.

Therefore, this embodiment mainly introduces the basic design of an MEA water splitting device used in water splitting catalysis. As an alternative structure, it specifically includes a nickel mesh stack and MEA equipment, and the nickel mesh stack is placed in the MEA equipment;

Please refer to Figure 1. Figure 1 is a side view of the nickel mesh stack provided by the present application. The nickel mesh stack includes two layers of nickel mesh with different pores.

Further, the nickel mesh stack includes a 60-mesh nickel mesh and a 300-mesh nickel mesh. Please refer to Figures 3 and 4. Figure 3 is a front SEM image of the 300-mesh and 60-mesh nickel mesh stacks provided by this application; Figure 4 is the reverse SEM image of the 300-mesh and 60-mesh nickel mesh stack provided by this application. For details, please refer to Figure 10, which shows SEM pictures of nickel mesh 300|60 under different pressures.

Further, the length of the two layers of nickel mesh is 1 cm and the width is 1 cm.

Further, the area of the nickel mesh stack is 1 cm ² .

The nickel mesh laminate designed in this application is a nickel mesh that has undergone physical high-pressure treatment. The nickel mesh laminate has a smooth plane to avoid membrane damage during the installation process.

Example 2

Based on the above Embodiment 1, this embodiment mainly introduces a preparation method of an MEA water splitting device used in water splitting catalysis, which includes the following steps:

Step S1: Put the industrial pure nickel mesh with a mesh number of 60 and the industrial pure nickel mesh with a mesh number of 300 into a beaker;

Step S2: Pour the pure HCl solution into the beaker so that the nickel mesh is completely submerged;

Step S3: Cover the beaker with a sealing film to prevent the HCl solution from evaporating or overflowing, and then put it into an ultrasonic cleaner for cleaning until the color of the solution changes from colorless to blue-green;

Step S4: Wash the acid-treated mesh with water and ethanol to remove any unwanted debris and grease;

Step S5: Completely align the two processed nickel meshes, and then put them into a tablet press to make a nickel mesh stack.

Step S6: Place the nickel mesh stack into the MEA equipment.

Further, the pure HCl solution in step S2 is a 3 mol HCl solution.

Further, in step S3, the cleaning time is 1 to 3 h.

Further, in step S5, the applied pressure of the tablet press is 10 MPa.

Further, in step S5, the length of the two nickel meshes is 1 cm and the width is 1 cm.

Furthermore, a thin film is provided on the outside of the 300-mesh nickel mesh.

This application designs a preparation method for an MEA water splitting device used in water splitting catalysis. Compared with the traditional complex composite catalyst preparation method, the combination method and materials of the present invention can achieve and be superior to the more complex preparation methods reported in the literature. Catalytic properties, and the catalyst grown on the system of the method of the present invention has improved performance. By using COMSOL for simulation, we found that this assembly method can not only solve the mass transfer problem, but also achieve more uniform current and voltage density. distribution, which is consistent with the experimental results.

Example 3

Based on the above Embodiment 1-2, this embodiment mainly introduces the verification of the effect of an MEA water splitting device used in water splitting catalysis.

The research on mass transfer is clearly reflected from the single piece. Please refer to Figure 2. Figure 2 is a comparison chart of the mass transfer effect of the single mesh nickel mesh provided by this application; the single layer with different mesh numbers of 60, 100, 300, and 400 is used as There are obvious differences in the performance of water electrolysis catalysts; it can be seen from the figure that 300 mesh has the best performance and 100 mesh has the worst performance. It also shows that mass transfer plays an important role in the MEA system. If only active sites on the surface are considered, the highest mesh number will have the best performance. However, the results do not support this hypothesis: Please refer to 5, at 2.0 A and 2.4 V, the anode catalyst with mesh number 300 performed 20.23% and 14.55% better than the anode catalyst with mesh number 400 and the anode catalyst with mesh number 60, respectively. The performance is 19.76% better and the performance is 35.78% higher than 100.

When surface area increases, there are more active sites for reactions to occur. This basic knowledge led the research a step further to test the performance of the double layer nickel mesh. Given the results shown in Figure 2, there is simply no way to predict performance from screening. Therefore, considering all possible combinations of different screenings, please refer to Figure 5, the average mesh number of membrane |300|60 and membrane |60|300 prepared by the present invention performed best at 80oC.

Referring to Figure 6, it can be seen from the single mesh results that the highest performance at 2.4V is 3.81 A cm ^-2 and 3.98 A cm ^-2 for mesh counts of 300 and 60, respectively, while when these two are combined When together, the current density values can be as high as 6.95 cm ^-2 which is an increase of 82.41% compared to 300 mesh and 74.62% compared to 60 mesh. This may be explained by active sites, the more nickel, the better the performance. However, once the results of Membrane|300|60 and Membrane|60|300 are compared, given that the two catalysts have the same active sites and the only difference is the surface structure, Membrane|300|60 performs 13.38% better, proving this The mass transfer limitations were greatly affected by the invention.

Please refer to Figure 7. In the three-electrode system, the formation and removal time of bubbles on a single 60-mesh nickel mesh is 169 seconds, and the time from generation to bubble formation for 300-mesh nickel mesh is 194 seconds. The combined test of 300|60 mesh of the present invention, The time for bubble formation and removal is 42 seconds. As mentioned above, 300|60 designed by the present invention has the optimal water decomposition promotion function.

Figure 8 illustrates the comparison between the pure nickel production method of the present invention and the complex composite catalyst. The combined method and materials of the present invention can achieve and be superior to the catalytic properties of more complex preparations reported in the literature. Figure 9 is a performance diagram of the nickel mesh 300|60 provided by this application under different pressures; Figure 10 is an SEM picture of the nickel mesh 300|60 provided by this application under different pressures. It can be clearly concluded from Figure 9 that The nickel mesh laminate prepared under 10MPa pressure has the best effect.

The above descriptions are only preferred embodiments of the present invention, which do not limit the scope of the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any changes, modifications, substitutions, integrations, and parameter changes to these embodiments that are within the spirit and spirit of the present invention through conventional substitutions or can achieve the same functions without departing from the principles and spirit of the present invention shall fall within the scope of the present invention. into the protection scope of the present invention.

Claims (8)

1. An MEA water splitting device used in water splitting catalysis, characterized in that it includes a nickel mesh stack and MEA equipment, and the nickel mesh stack is placed in the MEA equipment; The nickel mesh stack includes two layers of nickel mesh with different pores; The nickel mesh laminate includes a 60-mesh nickel mesh and a 300-mesh nickel mesh. The nickel mesh laminate is a nickel mesh laminate that has been subjected to physical high-pressure treatment, in which the high-pressure applied pressure is 10 MPa. 2. A MEA water splitting device used in water splitting catalysis according to claim 1, characterized in that the length of the two layers of nickel mesh is 0.5~2 cm and the width is 0.5~2 cm. 3. An MEA water splitting device for water splitting catalysis according to claim 1, characterized in that the area of the nickel mesh stack is 1 cm ² . 4. The preparation method of an MEA water splitting device used in water splitting catalysis according to any one of claims 1 to 3, characterized in that it includes the following steps: Step S1: Put the industrial pure nickel mesh with a mesh number of 60 and the industrial pure nickel mesh with a mesh number of 300 into a beaker; Step S2: Pour the pure HCl solution into the beaker so that the nickel mesh is completely submerged; Step S3: Cover the beaker with a sealing film to prevent the HCl solution from evaporating or overflowing, and then put it into an ultrasonic cleaner for cleaning until the color of the solution changes from colorless to blue-green; Step S4: Wash the acid-treated mesh with water and ethanol to remove any unwanted debris and grease; Step S5: Completely align the two processed nickel meshes, and then put them into a tablet press to make a nickel mesh stack; Step S6: Place the nickel mesh stack into the MEA equipment; Wherein, in step S5, the applied pressure of the tablet press is 10 MPa. 5. A method for preparing an MEA water splitting device for water splitting catalysis according to claim 4, characterized in that the pure HCl solution in step S2 is a 3 mol HCl solution. 6. The method for preparing an MEA water splitting device used in water splitting catalysis according to claim 4, characterized in that in step S3, the cleaning time is 1 to 3 h. 7. A method for preparing an MEA water splitting device used in water splitting catalysis according to claim 4, characterized in that in step S5, the length of the two nickel meshes is 1 cm and the width is 1 cm. . 8. The method for preparing an MEA water splitting device used in water splitting catalysis according to claim 4, characterized in that a thin film is provided outside the 300-mesh nickel mesh.