CN115505947B

CN115505947B - A method for preparing a membrane electrode for water electrolysis

Info

Publication number: CN115505947B
Application number: CN202211134131.XA
Authority: CN
Inventors: 赵长明
Original assignee: Anhui Entropy Card Technology Co ltd
Current assignee: Anhui Entropy Card Technology Co ltd
Priority date: 2022-09-15
Filing date: 2022-09-15
Publication date: 2025-01-28
Anticipated expiration: 2042-09-15
Also published as: CN115505947A

Abstract

The invention discloses a preparation method of a membrane electrode for water electrolysis, which comprises the following steps of arranging a first carrier layer on the upper surface of a transfer printing substrate, arranging a second carrier layer on the upper surface of another transfer printing substrate, arranging a cathode catalytic layer on the first carrier layer, arranging an anode catalytic layer on the second carrier layer, respectively arranging the anode catalytic layer and the cathode catalytic layer on two sides of a proton exchange membrane, carrying out hot pressing treatment to obtain a composite membrane, and arranging the composite membrane in a solvent to dissolve the first carrier layer and the second carrier layer in the solvent to obtain the membrane electrode for water electrolysis, wherein the material of the first carrier layer comprises a high molecular polymer, and the material of the second carrier layer comprises the high molecular polymer. The membrane electrode for electrolyzed water prepared by the preparation method provided by the invention has the advantages of good performance, long service life, stable quality and high yield, and is suitable for large-scale production.

Description

Preparation method of membrane electrode for water electrolysis

Technical Field

The invention relates to the technical field of electrolyzed water, in particular to a preparation method of a membrane electrode for electrolyzed water.

Background

Hydrogen energy is a new energy source with wide application prospect. The energy source device has the advantages of high energy density, reproducibility and zero carbon emission, and is hopeful to realize the substitution of fossil energy sources in the future development, thereby guaranteeing the sustainable supply of the energy sources. The technology for producing hydrogen by electrolyzing water can realize direct conversion from electric energy to hydrogen energy, and can be combined with renewable energy sources to form an economical, efficient and environment-optimized hydrogen production industry.

The Solid Polymer Electrolyte (SPE) water electrolysis technology has the advantages of small equipment volume, quick start, high current density and high gas production purity, and is an important research direction of the current water electrolysis technology. The SPE water electrolysis technology uses a Proton Exchange Membrane (PEM) as a solid electrolyte to replace a diaphragm and a strong alkaline electrolyte in the traditional alkaline water electrolysis technology, so that the ion transmission efficiency is improved, and the corrosion effect of strong alkali on equipment is avoided. In the SPE water electrolysis technology, the membrane electrode is a composite structure with catalysis, conductivity and proton transmission functions, and is a core component of the whole electrolytic tank system. Existing membrane electrode structures include a PEM and cathode and anode catalytic layers on either side.

Currently, common processes for supporting a catalytic layer on a PEM include ultrasonic spraying and transfer printing. The transfer printing method is to coat the catalyst on the surface of the transfer printing substrate first, then transfer the catalyst to the PEM, and has the advantages of high yield, no swelling and little pollution, but when the catalyst slurry is coated on the transfer printing substrate, the phenomenon of uneven catalyst load is easy to occur, and due to certain adhesive force between the catalyst layer and the transfer printing substrate, the incomplete transfer printing of the catalyst layer and even the transfer printing failure often occur in the transfer printing process, and the two conditions can lead to unstable quality and low yield of the finally prepared catalyst layer, thereby limiting the mass production of the membrane electrode for electrolytic water.

Disclosure of Invention

The invention mainly aims to provide a preparation method of a membrane electrode for water electrolysis, which aims to solve the problems of unstable quality and low yield of a catalytic layer prepared by the existing transfer printing method.

In order to achieve the above object, the present invention provides a method for preparing a membrane electrode for electrolysis of water, comprising the steps of:

Disposing a first carrier layer on an upper surface of a transfer substrate;

providing a second carrier layer on the upper surface of the other transfer substrate;

disposing a cathode catalytic layer on the first support layer;

disposing an anode catalytic layer on the second support layer;

The cathode catalytic layer and the anode catalytic layer are respectively arranged on two sides of a proton exchange membrane, the cathode catalytic layer is contacted with the proton exchange membrane, the anode catalytic layer is contacted with the proton exchange membrane, and the composite membrane is obtained through hot pressing treatment;

Placing the composite membrane in a solvent to dissolve the first carrier layer and the second carrier layer in the solvent to obtain a membrane electrode for water electrolysis;

the material of the first carrier layer comprises a high polymer, and the material of the second carrier layer comprises a high polymer.

Optionally, the material of the transfer substrate includes at least one of polytetrafluoroethylene, fluorinated ethylene propylene copolymer, perfluoroalkoxy copolymer, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer.

Optionally, the material of the first carrier layer comprises at least one of polyvinyl alcohol, polyethylene oxide, polymethyl pyrrolidone, polyacrylamide and polyacrylic acid, and/or,

The second carrier layer is made of at least one of polyvinyl alcohol, polyethylene oxide, polymethyl pyrrolidone, polyacrylamide and polyacrylic acid.

Optionally, the step of disposing a cathode catalytic layer on the first support layer comprises:

and coating the cathode catalyst slurry on the upper surface of the first carrier layer, and drying to obtain the cathode catalyst layer, wherein the cathode catalyst slurry comprises a cathode catalyst, a dispersing agent and a binder.

Optionally, the cathode catalyst comprises Pt/C, and/or,

The dispersant comprises at least one of water, ethanol, isopropanol and n-propanol, and/or,

The drying temperature of the drying is 50-90 ℃ and/or,

The manner of applying the cathode catalyst slurry includes any one of knife coating, brush coating and screen printing.

Optionally, the cathode catalyst loading of the cathode catalyst layer is 0.5-5 mg cm ^-2.

Optionally, the step of disposing an anode catalytic layer on the second support layer comprises:

and coating the cathode catalyst slurry on the upper surface of the first carrier layer, and drying to obtain the cathode catalyst layer, wherein the anode catalyst slurry comprises an anode catalyst, a dispersing agent and a binder.

Optionally, the anode catalyst comprises iridium dioxide, and/or,

The drying temperature of the drying is 50-90 ℃ and/or,

The manner of applying the anode catalyst slurry includes any one of knife coating, brush coating and screen printing.

Optionally, the anode catalyst layer carries an anode catalyst loading of 0.5-5 mg cm ^-2.

Optionally, in the hot pressing treatment step, the hot pressing temperature is 90-140 ℃, the hot pressing pressure is 0.2-5.0 MPa, and the hot pressing time is 1-10 min.

According to the technical scheme, the carrier layer is arranged between the transfer printing substrate and the catalytic layer, the problem of incomplete transfer printing caused by adhesion of the catalytic layer to the transfer printing substrate is avoided, so that the catalytic layer is stable in quality and high in transfer printing efficiency, the carrier layer is made of high-molecular polymers, and therefore has higher surface tension than the transfer printing substrate, the carrier layer is more easily soaked by catalyst slurry, and therefore the load uniformity of the catalytic layer is good, in addition, the carrier layer can be removed in the subsequent treatment process, interference on the performance of a membrane electrode is avoided, and the removal mode is simple. Therefore, the membrane electrode for electrolyzed water prepared by the preparation method provided by the invention has the advantages of good performance, long service life, stable quality and high yield, and is suitable for mass production.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other related drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic flow chart of an embodiment of a method for preparing a membrane electrode for water electrolysis according to the present invention;

FIG. 2 is a scanning electron microscope image of the membrane electrode prepared in example 1 of the present invention;

FIG. 3 is a graph showing the comparison of actual transfer effects during the preparation of the membrane electrode in example 1 and comparative example 1 of the present invention;

FIG. 4 is a graph showing the results of performance tests of the membrane electrodes prepared in example 1 and comparative example 1 of the present invention.

Reference numerals illustrate:

Reference numerals	Name of the name	Reference numerals	Name of the name
				1	Transfer substrate	3	Cathode catalytic layer
21	A first carrier layer	4	Anode catalytic layer
				22	Second carrier layer	5	Proton exchange membrane

The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

In addition, the meaning of "and/or" as it appears throughout includes three parallel schemes, for example "A and/or B", including the A scheme, or the B scheme, or the scheme where A and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Currently, common processes for supporting a catalytic layer on a PEM include ultrasonic spraying and transfer printing. The transfer printing method is characterized in that a catalyst is coated on the surface of a transfer printing substrate and then transferred to a PEM, so that the transfer printing method has the advantages of high yield, no swelling and little pollution, but when the catalyst slurry is coated on the transfer printing substrate, the phenomenon of uneven catalyst loading is easy to occur, and a certain adhesive force exists between a catalytic layer and the transfer printing substrate due to the fact that the catalyst slurry contains a binder, so that the situation that the catalytic layer is not completely transferred and even fails in transfer printing often occurs in the transfer printing process, and the quality of a finally prepared catalytic layer is unstable and the yield is low, so that the mass production of the membrane electrode for water electrolysis is limited.

In view of this, the present invention proposes a method for preparing a membrane electrode for electrolysis of water, which in one embodiment comprises the steps of:

step S10, disposing a first carrier layer 21 on the upper surface of a transfer substrate 1.

Step S20, disposing a second carrier layer 22 on the upper surface of the other transfer substrate 1.

The first carrier layer 21 comprises a high molecular polymer and the second carrier layer 22 comprises a high molecular polymer. For convenience of description, the support layers are hereinafter collectively referred to when describing the common characteristics of the first support layer 21 and the second support layer 22, and the catalytic layers are hereinafter collectively referred to when describing the common characteristics of the cathode catalytic layer 3 and the anode catalytic layer 4.

The carrier layer is arranged between the transfer printing substrate 1 and the catalytic layer, so that direct contact between the transfer printing substrate 1 and the catalytic layer is avoided, complete transfer printing of the catalytic layer can be realized during transfer printing, transfer printing efficiency is high, the quality of the catalytic layer obtained through transfer printing is stable, the high-molecular polymer is a material with high surface tension, the prepared carrier layer has higher surface tension than that of the transfer printing substrate 1 and is more easily infiltrated by catalyst slurry, the loading uniformity of the catalytic layer is improved, the improvement of membrane electrode performance and service life is facilitated, and in addition, the high-molecular polymer is a soluble material, so that the residual carrier layer on the membrane electrode can be removed in a solvent dissolving mode, and the negative influence of the carrier layer residue on the membrane electrode performance is avoided.

In this embodiment, the transfer substrate 1 is a sheet-like film. Further, the material of the transfer substrate 1 is at least one of Polytetrafluoroethylene (PTFE), fluorinated ethylene propylene copolymer (FEP), perfluoroalkoxy copolymer (PFA), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene copolymer (ETFE).

It should be noted that, in other embodiments of the present invention, the step S20 may be performed before the step S10, or the step S20 and the step S10 may be performed simultaneously, and only the preparation of the first carrier layer 21 and the second carrier layer 22 may be completed before the next step (i.e. before the step S30, the step S10 is completed, and before the step S40, the step S20 is completed). Referring to fig. 1 in combination, in this embodiment, step S10 and step S20 are performed simultaneously.

The material of the first carrier layer 21 includes a high molecular polymer, and the present invention is not limited to a specific type of high molecular polymer, as long as the high molecular polymer is soluble in water or an organic solvent under normal conditions. Preferably, the high molecular polymer is a water-soluble high molecular polymer, so that the carrier layer can be dissolved only by adding water in the subsequent treatment process, thereby achieving the purpose of removal and being more environment-friendly. Further, the first carrier layer 21 includes at least one of polyvinyl alcohol (PVA), polyethylene oxide (PEO), polymethylpyrrolidone (PVP), polyacrylamide (PAM), and polyacrylic acid (PAA).

The material of the second carrier layer 22 includes a high molecular polymer, and for the same reason as the first carrier layer 21, preferably, the material of the second carrier layer 22 includes at least one of polyvinyl alcohol (PVA), polyethylene oxide (PEO), polymethyl pyrrolidone (PVP), polyacrylamide (PAM), and polyacrylic acid (PAA).

The materials of the first carrier layer 21 and the second carrier layer 22 may be the same or different. In order to facilitate the operation and control the hot pressing conditions, in this embodiment, the materials of the first carrier layer 21 and the second carrier layer 22 are the same, so that the step S10 and the step S20 may be combined into one step, i.e., the carrier layer is disposed on the transfer substrate.

The specific arrangement mode of the carrier layer on the transfer printing substrate 1 is not limited, and in the embodiment, the method is realized by any one of (1) cutting a high polymer film with consistent size and attaching the film on the surface of the transfer printing substrate 1, and (2) preparing the high polymer into carrier layer slurry by dispersing or dissolving the high polymer in a solvent, coating the slurry on the surface of the transfer printing substrate 1 and drying.

Step S30, disposing a cathode catalytic layer 3 on the first support layer 21.

In practice, the cathode catalyst slurry is coated on the upper surface of the first support layer 21, and then dried to obtain the cathode catalyst layer 3.

Wherein the cathode catalyst slurry comprises a cathode catalyst, a dispersant and a binder. Further, the cathode catalyst includes Pt/C. In another embodiment, the dispersant includes at least one of water, ethanol, isopropanol, and n-propanol. In another embodiment, the binder comprises a perfluorosulfonic acid resin solution. Preferably, in the cathode catalyst slurry, the concentration of the cathode catalyst is 2-20 mg/mL, and the mass of the binder is 20-50% of the mass of the cathode catalyst.

In order to make the catalytic performance of the prepared membrane electrode better, the cathode catalyst loading of the cathode catalyst layer 3 is preferably 0.5-5 mg cm ^-2. Further, the manner of applying the cathode catalyst slurry includes any one of knife coating, brush coating, and screen printing. In addition, the drying temperature of the drying is 50-90 ℃.

Step S40, disposing an anode catalytic layer on the second carrier layer.

Specifically, the anode catalyst slurry is coated on the surface of the second support layer 22, and then dried to obtain the anode catalyst layer 4.

The specific drying temperature is not limited in the present invention, and in this embodiment, the drying temperature is 50-90 ℃, so the drying speed is suitable.

Wherein the anode catalyst slurry comprises an anode catalyst, a dispersant and a binder. In one embodiment, the anode catalyst comprises iridium dioxide (IrO ₂). In another embodiment, the dispersant includes at least one of water, ethanol, isopropanol, and n-propanol. In another embodiment, the binder comprises a perfluorosulfonic acid resin solution. Preferably, in the anode catalyst slurry, the concentration of the anode catalyst is 2-20 mg/mL, and the mass of the binder is 20-50% of the mass of the cathode catalyst.

In order to make the catalytic performance of the prepared membrane electrode better, the anode catalyst loading on the second carrier layer 22 is preferably 0.5-5 mg cm ^-2. Further, the manner of applying the anode catalyst slurry includes any one of knife coating, brush coating, and screen printing.

In other embodiments of the present invention, the step S40 may be performed before the step S30, or the step S30 and the step S40 may be performed simultaneously, and only need to be completed before the next step (i.e., before the step S50). Referring to fig. 1 in combination, in this embodiment, step S30 and step S40 are performed simultaneously.

And S50, respectively placing the cathode catalytic layer 3 and the anode catalytic layer 4 on two sides of the proton exchange membrane 5, enabling the cathode catalytic layer 3 to be in contact with the proton exchange membrane 5, enabling the anode catalytic layer 4 to be in contact with the proton exchange membrane 5, and carrying out hot pressing treatment to obtain the composite membrane.

The anode catalytic layer 4 and the cathode catalytic layer 3 are transferred to both sides of the proton exchange membrane 5 by hot press treatment, respectively. If the temperature, time or pressure of the hot pressing is too high, the structure of the proton exchange membrane 5 or the catalytic layer may be damaged, if too low, the incomplete transfer or even the transfer failure of the catalytic layer may be caused, in this embodiment, the hot pressing temperature of the hot pressing treatment is 90-140 ℃, the hot pressing pressure is 0.2-5.0 mpa, and the hot pressing time is 1-10 min, so that the transfer of the catalytic layer is complete, and the structure of the proton exchange membrane 5 or the catalytic layer may not be damaged.

Step S60, placing the composite membrane in a solvent to dissolve the first carrier layer 21 and the second carrier layer 22 in the solvent, thereby obtaining a membrane electrode for water electrolysis.

In this step, the first support layer 21 and the second support layer 22 are removed, and the negative influence of the support layer residue on the membrane electrode performance is avoided. According to the invention, the material of the carrier layer is designed, so that the composite film is placed in a solvent and then taken out, so that the first carrier layer 21 and the second carrier layer 22 can be removed, and the operation is simple.

The present invention is not limited as long as the first support layer 21 and the second support layer 22 can be dissolved, as long as the specific choice of the solvent is made. In this embodiment, the first carrier layer 21 and the second carrier layer 22 are both water-soluble polymers, so the solvent is water.

In conclusion, the preparation method of the membrane electrode for the electrolyzed water has the advantages of simplicity in operation, environment friendliness, long service life, stable quality and high yield, and the prepared membrane electrode for the electrolyzed water is suitable for mass production.

The following technical solutions of the present invention will be described in further detail with reference to specific examples and drawings, and it should be understood that the following examples are only for explaining the present invention and are not intended to limit the present invention.

The formulations of the cathode catalyst slurry and anode catalyst slurry in examples 1-4 are given below:

And (3) cathode catalyst slurry, namely uniformly dispersing IrO ₂ catalyst and 5wt% of perfluorinated sulfonic acid resin solution in a dispersing agent with the volume ratio of water to ethanol being 1:1. Wherein the content of IrO ₂ is 10 mg/mL ^-1, and the mass of the perfluorinated sulfonic acid resin is 40% of that of IrO ₂;

Anode catalyst slurry 40wt% Pt/C catalyst and 5wt% perfluorinated sulfonic acid resin solution are uniformly dispersed in a dispersing agent with the volume ratio of water to ethanol being 1:1. Wherein, 40wt% of Pt/C content is 10 mg.mL ^-1, and 40% of the mass of the perfluorinated sulfonic acid resin is 40% of the mass of 40wt% of Pt/C.

Example 1

(1) Cutting a 50mm multiplied by 50mm PTFE film to serve as a transfer printing substrate, and then cutting a 50mm multiplied by 50mm polyvinyl alcohol film to be attached to the surface of the transfer printing substrate to obtain a carrier layer;

(2) A transfer printing substrate paved with a carrier layer (namely a first carrier layer) is taken, cathode catalyst slurry is brushed on the surface of the carrier layer, and the cathode catalyst layer is obtained by heating and drying at 70 ℃, wherein the cathode catalyst loading is 1mg cm ^-2;

(3) Taking another transfer printing substrate paved with a carrier layer (namely a second carrier layer), brushing anode catalyst slurry on the surface of the carrier layer, and heating and drying at 70 ℃ to obtain an anode catalyst layer, wherein the anode catalyst loading is 2mg cm ^-2;

(4) Cutting a piece of Nafion117 proton exchange membrane with the thickness of 60mm multiplied by 60mm, placing the Nafion117 proton exchange membrane between a transfer printing substrate provided with a cathode catalytic layer and a transfer printing substrate provided with an anode catalytic layer, and carrying out hot pressing for 3min at 130 ℃ and 1.0MPa to obtain a composite membrane;

(5) And (3) immersing the composite membrane structure after hot pressing in deionized water for 30min to remove the carrier layer, thereby obtaining the membrane electrode for water electrolysis.

The membrane electrode for electrolytic water prepared in this example was observed under a scanning electron microscope, and the results are shown in FIG. 2. As can be seen from fig. 2, the uniformity of the cathode catalytic layer and the anode catalytic layer on the membrane electrode is good, which means that the uniformity of the load is good and the transfer is complete in the transfer process when the catalyst slurry is coated on the support layer.

Example 2

(1) Cutting 80mm multiplied by 80mm PFA film as a transfer printing substrate, dissolving 5g of polyvinylpyrrolidone in 100mL of deionized water to prepare carrier layer slurry, scraping the slurry on the surface of PTFE film, and drying to obtain a carrier layer;

(2) A transfer printing substrate paved with a carrier layer (namely a first carrier layer) is taken, cathode catalyst slurry is coated on the surface of the carrier layer in a scraping way, and the cathode catalyst layer is obtained by heating and drying at 90 ℃, wherein the cathode catalyst loading is 0.5mg cm ^-2;

(3) Another transfer printing substrate paved with a carrier layer (namely a second carrier layer) is taken, anode catalyst slurry is coated on the surface of the carrier layer in a scraping way, and the anode catalyst layer is obtained by heating and drying at 90 ℃, wherein the anode catalyst loading is 1.5mg cm ^-2;

(4) Cutting a piece of Nafion 117 proton exchange membrane with the diameter of 90mm multiplied by 90mm, placing the Nafion 117 proton exchange membrane between a transfer printing substrate provided with a cathode catalytic layer and a transfer printing substrate provided with an anode catalytic layer, and hot-pressing for 2min at 120 ℃ and 1.5MPa to obtain a composite membrane;

(5) And (3) immersing the composite membrane structure after hot pressing in deionized water for 30min, and removing residual carrier layer components to obtain the membrane electrode for water electrolysis.

Example 3

(1) Cutting a 50mm multiplied by 50mm FEP film as a transfer printing substrate, dissolving 5g polyacrylamide in 100mL deionized water to prepare carrier layer slurry, brushing the slurry on the surface of the PTFE film, and drying to obtain a carrier layer;

(2) A transfer printing substrate paved with a carrier layer (namely a first carrier layer) is taken, cathode catalyst slurry is brushed on the surface of the carrier layer, and the cathode catalyst layer is obtained by heating and drying at 50 ℃, wherein the cathode catalyst loading is 2mg cm ^-2;

(3) Taking another transfer printing substrate paved with a carrier layer (namely a second carrier layer), brushing anode catalyst slurry on the surface of the carrier layer, and heating and drying at 50 ℃ to obtain an anode catalyst layer, wherein the anode catalyst loading is 4mg cm ^-2;

(4) Cutting a piece of Nafion117 proton exchange membrane with the thickness of 60mm multiplied by 60mm, placing the Nafion117 proton exchange membrane between a transfer printing substrate provided with a cathode catalytic layer and a transfer printing substrate provided with an anode catalytic layer, and carrying out hot pressing for 5min at the temperature of 90 ℃ and under the pressure of 5.0MPa to obtain a composite membrane;

Example 4

(1) Taking a PVDF film with the size of 50mm multiplied by 50mm as a transfer printing substrate, and attaching a polyethylene oxide film with the size of 50mm multiplied by 50mm to the surface of the transfer printing substrate to obtain a first carrier layer;

(2) Taking a PVDF film with the size of 50mm multiplied by 50mm as a transfer printing substrate, and attaching a polyacrylic acid film with the size of 50mm multiplied by 50mm to the surface of the transfer printing substrate to obtain a second carrier layer;

(3) Brushing the cathode catalyst slurry on the surface of the first carrier layer, and heating and drying at 60 ℃ to obtain a cathode catalyst layer, wherein the cathode catalyst loading is 5mg cm ^-2;

(4) Brushing anode catalyst slurry on the surface of the second carrier layer, and heating and drying at 60 ℃ to obtain an anode catalyst layer, wherein the anode catalyst loading is 4mg cm ^-2;

(5) Cutting a piece of Nafion 117 proton exchange membrane with the thickness of 60mm multiplied by 60mm, placing the Nafion 117 proton exchange membrane between a transfer printing substrate provided with a cathode catalytic layer and a transfer printing substrate provided with an anode catalytic layer, and performing hot pressing for 10min at 100 ℃ and 0.2MPa to obtain a composite membrane;

(6) And (3) immersing the composite membrane structure after hot pressing in deionized water for 30min, and removing the residual components of the first carrier layer and the second carrier layer to obtain the membrane electrode for water electrolysis.

Example 5

The procedure of example 1 was repeated except that the hot-pressing step of step (4) was modified to hot-press at 140℃and 2MPa for 1min to obtain a composite film.

Example 6

The procedure of example 1 was repeated except that the loading of the cathode catalyst was changed to 2mg cm ^-2 and the anode catalyst loading was changed to 5mg cm ^-2.

Comparative example 1

The procedure was the same as in example 1, except that no support layer was provided, i.e., the procedure was as follows:

(1) Cutting a 50mm multiplied by 50mm PTFE film to serve as a transfer printing substrate;

(2) A piece of transfer printing substrate is taken, the surface of the carrier layer is coated with cathode catalyst slurry, and the cathode catalyst slurry is heated and dried at 70 ℃ to obtain a cathode catalyst layer, wherein the cathode catalyst loading is 1mg cm ^-2;

(3) Another transfer printing substrate is taken, anode catalyst slurry is brushed on the surface of the carrier layer, and the anode catalyst slurry is heated and dried at 70 ℃ to obtain an anode catalyst layer, wherein the anode catalyst loading is 2mg cm ^-2;

Investigation of transfer Effect

The anode catalytic layers of the membrane electrodes for water electrolysis prepared in example 1 and comparative example 1 were observed under an electron microscope, and the results are shown in fig. 3.

As can be seen from fig. 3, the anode catalyst layer of example 1 was uniformly transferred to the surface of the proton exchange membrane, whereas the anode catalyst layer of comparative example 1 showed a significant transfer unevenness on the right side.

(II) catalytic Performance test

The obtained membrane electrodes for electrolyzed water prepared in example 1 and comparative example 1 were placed in an SPE electrolyzed water test system to conduct a test. The test conditions were constant current density 2A cm ^-2, temperature 80℃and membrane electrode working area 20cm ². The specific test results are shown in fig. 4.

As can be seen from fig. 4, the membrane electrode in example 1 had an initial voltage of 1.85V, which has a lower overpotential than comparative example 1, in which no support layer was added. Meanwhile, in the subsequent test, the voltage of the membrane electrode in the example 1 increases more slowly, and the more excellent electrolyzed water catalytic performance and stability are reflected.

(III) quality stability test

The 10 membrane electrodes for electrolyzed water prepared in example 1 and comparative example 1 were placed in an SPE electrolyzed water testing system to test the initial operating voltage. The test conditions were constant current density 2A cm ^-2, temperature 80℃and membrane electrode working area 20cm ². The test results are shown in table 1 below. TABLE 1 quality stability test results

As can be seen from table 1, in the membrane electrode samples prepared in example 1, the initial operating voltage of all samples was below 1.90V, and the sample quality was relatively stable. In the membrane electrode sample prepared in comparative example 1, the voltage of sample No. 4 and sample No. 10 is obviously higher, the voltage fluctuation between samples is more obvious, and the quality stability of the samples is poor.

The foregoing is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention, but various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a membrane electrode for water electrolysis, characterized in that it comprises the following steps:

Disposing a first carrier layer on an upper surface of a transfer substrate;

Disposing a second carrier layer on the upper surface of another transfer substrate;

Disposing a cathode catalyst layer on the first carrier layer;

Disposing an anode catalyst layer on the second carrier layer;

The cathode catalyst layer and the anode catalyst layer are respectively placed on both sides of the proton exchange membrane, and the cathode catalyst layer is in contact with the proton exchange membrane, and the anode catalyst layer is in contact with the proton exchange membrane, and subjected to hot pressing treatment to obtain a composite membrane;

Wherein, the material of the first carrier layer includes at least one of polyvinyl alcohol, polyethylene oxide, polymethylpyrrolidone, polyacrylamide and polyacrylic acid;

The material of the second carrier layer includes at least one of polyvinyl alcohol, polyethylene oxide, polymethyl pyrrolidone, polyacrylamide and polyacrylic acid.

2. The method for preparing a membrane electrode for water electrolysis according to claim 1, characterized in that the material of the transfer substrate includes at least one of polytetrafluoroethylene, fluorinated ethylene propylene copolymer, perfluoroalkoxy copolymer, polyvinylidene fluoride and ethylene-tetrafluoroethylene copolymer.

3. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein the step of providing a cathode catalyst layer on the first carrier layer comprises:

The cathode catalyst slurry is coated on the upper surface of the first carrier layer and then dried to obtain a cathode catalyst layer, wherein the cathode catalyst slurry includes a cathode catalyst, a dispersant and a binder.

4. The method for preparing a membrane electrode for water electrolysis according to claim 3, wherein the cathode catalyst comprises Pt/C; and/or,

The dispersant comprises at least one of water, ethanol, isopropanol and n-propanol; and/or,

The drying temperature of the drying is 50 to 90° C.; and/or,

The cathode catalyst slurry may be applied by any one of blade coating, brush coating and screen printing.

5 . The method for preparing a membrane electrode for water electrolysis according to claim 3 , wherein the cathode catalyst loading of the cathode catalyst layer is 0.5 to 5 mg·cm ⁻² .

6. The method for preparing a membrane electrode for water electrolysis according to claim 1, wherein the step of providing an anode catalyst layer on the second carrier layer comprises:

The cathode catalyst slurry is coated on the upper surface of the first carrier layer and dried to obtain a cathode catalyst layer, wherein the anode catalyst slurry includes an anode catalyst, a dispersant and a binder.

7. The method for preparing a membrane electrode for water electrolysis according to claim 6, wherein the anode catalyst comprises iridium dioxide; and/or,

The drying temperature of the drying is 50 to 90° C.; and/or,

The method of applying the anode catalyst slurry includes any one of blade coating, brush coating and screen printing.

8 . The method for preparing a membrane electrode for water electrolysis according to claim 6 , wherein the anode catalyst loading of the anode catalyst layer is 0.5 to 5 mg·cm ⁻² .

9. The method for preparing a membrane electrode for water electrolysis according to claim 1, characterized in that in the hot pressing step, the hot pressing temperature is 90-140°C, the hot pressing pressure is 0.2-5.0 MPa, and the hot pressing time is 1-10 min.