Preparation process of catalytic layer for electrolytic hydrogen production

Abstract

The preparation process of the catalytic layer for electrolytic hydrogen production comprises the following steps: preparation of catalyst slurry, preparation of the catalytic layer, transfer printing of the catalytic layer and treatment of the catalytic layer, and cathode catalyst slurry, anode catalyst slurry, a cathode catalytic layer and an anode catalytic layer which are coated on a base membrane, P-CCM and T-CCM are sequentially obtained through the steps. Exposure of catalyst active sites in the catalyst layer is effectively improved through in-situ etching, and the utilization rate of iridium oxide of the anode catalyst layer is improved, so that the performance is improved; by using the inorganic nano material as the pore template, the pore structures of the negative and positive catalyst layers can be effectively improved, and the gas transmission performance of the catalyst layers is improved, so that the performance of the catalyst layers is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic hydrogen production, and in particular to a preparation process of a catalytic layer for electrolytic hydrogen production. Background Art

[0002] In recent years, hydrogen energy, as an inevitable choice for deep decarbonization, has ushered in huge development opportunities. Green hydrogen has the advantage of "zero carbon emissions" in preparation, and has great room for carbon reduction, becoming one of the forms with the greatest development potential. Electrolysis of hydrogen is the most important mode of green hydrogen source and has attracted much attention. Among them, proton exchange membrane (PEM) electrolysis of hydrogen has the characteristics of fast response speed, compact electrolytic cell structure, small size, and high electrolytic cell efficiency. It is very suitable for the field of hydrogen production by coupling fluctuating renewable energy such as wind power and photovoltaic power, and has become an effective way to promote the consumption of renewable energy. Therefore, PEM water electrolysis technology is hailed as one of the most promising water electrolysis hydrogen production technologies in the field of hydrogen production.

[0003] As attached Figure 1 As shown, the working principle of PEM electrolysis for hydrogen production is that water molecules are first decomposed into oxygen and hydrogen ions (H+) under the catalytic action of the iridium-based catalyst at the anode, and then H+ is transferred to the cathode catalyst layer through the PEM membrane, and then hydrogen is generated under the catalytic action of the platinum-based catalyst at the cathode. The catalytic reaction on the anode side involves a four-electron process, which is the main controlled place for the hydrogen production reaction. In addition, the catalyst used in the anode catalyst layer involves an expensive iridium-based catalyst. Therefore, the efficient use of iridium-based catalysts and the design of high-performance catalyst layers have become crucial issues in the preparation of anode catalyst layers. Among them, the utilization efficiency of iridium oxide is improved by designing the carrier iridium oxide, but the low conductivity and poor stability of the carrier greatly limit its application. In practical applications, iridium oxide is still the mainstream catalyst for the anode catalyst layer of PEM electrolysis for hydrogen production. As shown in the attached Figure 2 As shown in the figure, the conventional iridium oxide catalyst layer preparation process has a low utilization rate of iridium in the catalyst layer due to the secondary stacking between particles, resulting in poor performance. Therefore, the design and preparation of the catalyst layer is still an important limiting factor for efficient hydrogen production. Summary of the invention

[0004] The problem to be solved by the present invention is to provide a preparation process of a catalyst layer for electrolytic hydrogen production, improve the utilization rate of iridium oxide in the anode catalyst layer, and improve the performance of the catalyst layer.

[0005] To solve the above technical problem, a preparation process of a catalytic layer for hydrogen electrolysis provided by the present invention comprises the following steps:

[0006] S1: Preparation of catalyst slurry:

[0007] Preparation of cathode catalyst slurry: platinum carbon catalyst, metal oxide, ultrapure water, ion polymer solution and alcohol solution are weighed respectively, and added into a container in sequence, and high-speed shear dispersion is performed under the assistance of ultrasound, and then degassing is performed in a degassing machine;

[0008] Preparation of anode catalyst slurry: Weigh iridium oxide catalyst, metal oxide, ultrapure water, ion polymer solution and alcohol solution respectively, add them into a container in sequence, and perform high-speed shear dispersion under the assistance of ultrasound;

[0009] S2: Preparation of catalyst layer: The cathode catalyst slurry and the anode catalyst slurry prepared in step S1 are coated on the transfer base film by blade coating or slit coating, and after drying, the cathode catalyst layer and the anode catalyst layer coated on the base film are obtained;

[0010] S3: Transfer of catalyst layer: cutting the transfer membranes of the cathode catalyst layer and the anode catalyst layer obtained in step S2 according to the specified size, placing the proton exchange membrane between the cut cathode catalyst layer transfer membrane and the anode catalyst layer transfer membrane, aligning the transfer membranes with the cathode catalyst layer and the anode catalyst layer and performing hot pressing operations to transfer the cathode catalyst layer and the anode catalyst layer to the proton exchange membrane, and obtaining a catalyst coated membrane, i.e., an initial P-CCM;

[0011] S4: Treatment of the catalytic layer: The catalyst coated membrane obtained in step S3 is immersed in an alkaline solution, washed with deionized water, and then transferred to an acid solution for ion replacement. After the replacement is completed, it is washed with deionized water to obtain a treated catalyst coated membrane, namely T-CCM.

[0012] Preferably, when preparing the cathode catalyst slurry in step S1, the high-speed shear dispersion speed is 10000 rpm and the dispersion time is 1 hour; when preparing the anode catalyst slurry in step S1, the high-speed shear dispersion speed is 10000 rpm and the dispersion time is 1 hour.

[0013] Preferably, in step S3, the hot pressing temperature is 140° C., the hot pressing pressure is 5 MPa, and the hot pressing time is 5 min.

[0014] Preferably, the metal oxide in step S1 is any one of WO3 and MoO3 or a mixture of two thereof; the ionic polymer solution in step S1 is a perfluorosulfonic acid resin dispersion; the alcohol solution in step S1 is a mixture of any one or more of ethanol, isopropanol, and n-propanol; the alkaline solution in step S4 is a mixture of any one or more of KOH, NaOH, and LiOH; the acid solution in step S4 is a mixture of any one or more of sulfuric acid, nitric acid, acetic acid, and hydrochloric acid.

[0015] Preferably, the mass ratio of the metal oxide to the platinum carbon catalyst in step S1 is set to a range of 0-50wt%; the mass ratio of the metal oxide to the iridium oxide catalyst in step S1 is set to a range of 0-10wt%; the solid content of the anode slurry in step S1 is in a range of 10-20wt%, and the solid content of the cathode slurry is in a range of 25-35wt%; the mass ratio of the ion polymer to the platinum carbon catalyst in step S1 is in a range of 0.3-0.5, and the mass ratio of the ion polymer to the iridium oxide catalyst is in a range of 0.1-0.3.

[0016] Preferably, the mass ratio of the metal oxide to the platinum carbon catalyst in step S1 is set to a range of 5-10wt%; the mass ratio of the metal oxide to the iridium oxide catalyst in step S1 is set to a range of 2-5wt%; the solid content range of the anode slurry in step S1 is 15wt%, and the solid content range of the cathode slurry is 32wt%; the mass ratio range of the ion polymer to the platinum carbon catalyst in step S1 is 0.35, and the mass ratio range of the ion polymer to the iridium oxide catalyst is 0.15.

[0017] Preferably, the metal oxide in step S1 is MoO3; the ionic polymer solution in step S1 is Solvay's EW790 or EW870; the alcohol solution in step S1 is n-propanol; the alkaline solution in step S4 is NaOH; and the acid solution in step S4 is sulfuric acid.

[0018] The beneficial effects of the present invention are as follows: the present invention provides a preparation process for a catalytic layer for hydrogen production by electrolysis, which effectively improves the exposure of the catalyst active sites in the catalytic layer through in-situ etching, improves the utilization rate of iridium oxide in the anode catalytic layer, and thus improves the performance; by using inorganic nanomaterials as pore templates, the pore structure of the cathode and anode catalytic layers can be effectively improved, and the gas transmission performance of the catalytic layer can be improved, thereby improving the performance of the catalytic layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The working principle diagram of PEM electrolysis hydrogen production is illustrated.

[0020] Figure 2 The structure comparison diagram of the catalyst layer prepared by the process of the present invention and the traditional process is illustrated.

[0021] Figure 3 The performance comparison data of the catalytic layer prepared by the process of the present invention and the traditional process are illustrated. DETAILED DESCRIPTION

[0022] To make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments.

[0023] Based on the described embodiments of the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present disclosure.

[0024] Embodiment 1:

[0025] Preparation of cathode catalyst slurry: solid content is set to 15wt%, the mass ratio of oxide to catalyst is 0.1:1, the mass ratio of ion polymer to catalyst is 0.35; the mass ratio of alcohol to deionized water is 10:4. According to the formula, weigh 8.27g of carbon-supported platinum catalyst with a platinum content of 50wt%, 0.827g of molybdenum oxide, 16.94g of n-propanol, 42.36g of deionized water, and 11.58g of resin solution (Solvay, D79) with a solid content of 25wt%; add ultrapure water, cathode catalyst, molybdenum oxide, resin solution, and n-propanol in the container in sequence, perform high-speed shear dispersion at 10000rpm for 1h under 100W ultrasound, and perform degassing to obtain cathode catalyst slurry.

[0026] Preparation of anode catalyst slurry: The solid content of the slurry is set to 32wt%, the mass ratio of molybdenum oxide to iridium oxide catalyst is 0.05:1, the mass ratio of n-propanol to deionized water is 7:3, and the mass ratio of ion polymer to iridium oxide catalyst is 0.15. According to the formula, 11.03g of commercial iridium oxide, 0.55g of molybdenum oxide, 22.25g of deionized water, 9.53g of n-propanol, and 6.62g of a resin solution (solvay, D87) with a solid content of 25wt% are weighed, and high-speed shear dispersion is performed at 10000rpm under 100W ultrasound for 1h.

[0027] Preparation of the catalytic layer: The obtained cathode and anode catalyst slurries were coated on the PTFE membrane using a slit coater, and the cathode and anode catalyst layers attached to the transfer membrane were obtained after drying. The iridium loading in the anode catalyst layer was about 1.0 mg / cm2, and the platinum loading in the cathode catalyst layer was about 0.4 mg / cm2.

[0028] Transfer of the catalytic layer: Cut the transfer membrane with the cathode and anode catalytic layers into 5*5cm rectangles, place the proton exchange membrane N115 in the middle, and place the catalytic layers on both sides opposite to each other. Hot press at 140℃ and 5MPa for 5min to obtain a catalyst-coated membrane with an active area of ​​25cm2.

[0029] Treatment of the catalytic layer: The obtained catalyst-coated membrane was immersed in 0.5M NaOH alkaline solution for 1 hour, then repeatedly rinsed with deionized water for 3 times, then switched to 0.5M H2SO4 solution for ion exchange for 1 hour, and further rinsed repeatedly with deionized water for multiple times.

[0030] Embodiment 2:

[0031] Preparation of cathode catalyst slurry: solid content is set to 10wt%, the mass ratio of oxide to catalyst is 0.05:1, the mass ratio of ion polymer to catalyst is 0.35; the mass ratio of alcohol to deionized water is 10:4. According to the formula, weigh 5.52g of carbon-supported platinum catalyst with a platinum content of 50wt%, 0.275g of molybdenum oxide, 18.99g of n-propanol, 47.48g of deionized water, and 7.72g of resin solution (Solvay, D79) with a solid content of 25wt%; add ultrapure water, cathode catalyst, molybdenum oxide, resin solution, and n-propanol in the container in sequence, perform high-speed shear dispersion at 10000rpm for 1h under 100W ultrasound, and perform degassing to obtain cathode catalyst slurry.

[0032] Preparation of anode catalyst slurry: The solid content of the slurry is set to 25wt%, the mass ratio of molybdenum oxide to iridium oxide catalyst is 0.02:1, the mass ratio of n-propanol to deionized water is 7:3, and the mass ratio of ion polymer to iridium oxide catalyst is 0.15. According to the formula, 8.62g of commercial iridium oxide, 0.172g of molybdenum oxide, 25.22g of deionized water, 10.81g of n-propanol, and 6.62g of a resin solution (Solvay, D87) with a solid content of 25wt% are weighed.

[0033] Preparation of the catalytic layer: The obtained cathode and anode catalyst slurries were coated on the PTFE membrane using a slit coater, and the cathode and anode catalyst layers attached to the transfer membrane were obtained after drying. The iridium loading in the anode catalyst layer was about 1.0 mg / cm2, and the platinum loading in the cathode catalyst layer was about 0.4 mg / cm2.

[0034] Transfer of the catalytic layer: Cut the transfer membrane with the cathode and anode catalytic layers into 5*5cm rectangles, place the proton exchange membrane N115 in the middle, and place the catalytic layers on both sides opposite to each other. Hot press at 140℃ and 5MPa for 5min to obtain a catalyst-coated membrane with an active area of ​​25cm2.

[0035] Treatment of the catalytic layer: The obtained catalyst-coated membrane was immersed in 0.5M NaOH alkaline solution for 1 hour, then repeatedly rinsed with deionized water for 3 times, then switched to 0.5M H2SO4 solution for ion exchange for 1 hour, and further rinsed repeatedly with deionized water for multiple times.

[0036] The present invention provides a preparation process for a catalytic layer for hydrogen production by electrolysis, which effectively improves the exposure of the catalyst active sites in the catalytic layer through in-situ etching, improves the utilization rate of iridium oxide in the anode catalytic layer, and thus improves the performance; by using inorganic nanomaterials as pore templates, the pore structure of the cathode and anode catalytic layers can be effectively improved, and the gas transmission performance of the catalytic layer can be improved, thereby improving the performance of the catalytic layer.

[0037] Traditional process comparative example 1:

[0038] Preparation of cathode catalyst slurry: solid content is set to 15wt%, mass ratio of ion polymer to catalyst is 0.35; mass ratio of alcohol to deionized water is 10:4. According to the formula, weigh 8.27g of carbon-supported platinum catalyst with a platinum content of 50wt%, 17.1g of n-propanol, 42.95g of deionized water, and 11.58g of resin solution (solvay, D79) with a solid content of 25wt%; add ultrapure water, cathode catalyst, molybdenum oxide, resin solution, and n-propanol in the container in sequence, perform high-speed shear dispersion at 10000rpm for 1h under 100W ultrasound, and perform degassing to obtain cathode catalyst slurry.

[0039] Preparation of anode catalyst slurry: The solid content of the slurry is set to 32wt%, the mass ratio of n-propanol to deionized water is 7:3, and the mass ratio of ion polymer to iridium oxide catalyst is 0.15. According to the formula, 11.03g of commercial iridium oxide, 22.64g of deionized water, 9.7g of n-propanol, and 6.62g of resin solution (sol vay, D87) with a solid content of 25wt% are weighed.

[0040] Preparation of the catalytic layer: The obtained cathode and anode catalyst slurries were coated on the PTFE membrane using a slit coater, and the cathode and anode catalyst layers attached to the transfer membrane were obtained after drying. The iridium loading in the anode catalyst layer was about 1.0 mg / cm2, and the platinum loading in the cathode catalyst layer was about 0.4 mg / cm2.

[0041] Transfer of the catalytic layer: Cut the transfer membrane with the cathode and anode catalytic layers into 5*5cm rectangles, place the proton exchange membrane N115 in the middle, and place the catalytic layers on both sides opposite to each other. Hot press at 140℃ and 5MPa for 5min to obtain a catalyst-coated membrane with an active area of ​​25cm2.

[0042] Traditional process comparative example 2:

[0043] Preparation of cathode catalyst slurry: Preparation of cathode catalyst slurry: solid content is set to 15wt%, mass ratio of ion polymer to catalyst is 0.35; mass ratio of alcohol to deionized water is 10:4. According to the formula, weigh 8.27g of carbon-supported platinum catalyst with a platinum content of 50wt%, 17.1g of n-propanol, 42.95g of deionized water, and 11.58g of resin solution (solvay, D79) with a solid content of 25wt%; add ultrapure water, cathode catalyst, molybdenum oxide, resin solution, and n-propanol in the container in sequence, perform high-speed shear dispersion at 10000rpm for 1h under 100W ultrasound, and perform degassing to obtain cathode catalyst slurry.

[0044] Preparation of anode catalyst slurry: The solid content of the slurry is set to 32wt%, the mass ratio of molybdenum oxide to iridium oxide catalyst is 0.05:1, the mass ratio of n-propanol to deionized water is 7:3, and the mass ratio of ion polymer to iridium oxide catalyst is 0.15. According to the formula, 11.03g of commercial iridium oxide, 0.55g of molybdenum oxide, 22.25g of deionized water, 9.53 of n-propanol, and 6.62g of resin solution (sol vay, D87) with a solid content of 25wt% are weighed.

[0045] Preparation of the catalytic layer: The obtained cathode and anode catalyst slurries were coated on the PTFE membrane using a slit coater, and the cathode and anode catalyst layers attached to the transfer membrane were obtained after drying. The iridium loading in the anode catalyst layer was about 1.0 mg / cm2, and the platinum loading in the cathode catalyst layer was about 0.4 mg / cm2.

[0046] Transfer of the catalytic layer: Cut the transfer membrane with the cathode and anode catalytic layers into 5*5cm rectangles, place the proton exchange membrane N115 in the middle, and place the catalytic layers on both sides opposite to each other. Hot press at 140℃ and 5MPa for 5min to obtain a catalyst-coated membrane with an active area of ​​25cm2.

[0047] Treatment of the catalytic layer: The obtained catalyst-coated membrane was immersed in 0.5M NaOH alkaline solution for 1 hour, then repeatedly rinsed with deionized water for 3 times, then switched to 0.5M H2SO4 solution for ion exchange for 1 hour, and further rinsed repeatedly with deionized water for multiple times.

[0048] The cation layers provided by Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were assembled into an electrolyzer, and the electrochemical performance test of hydrogen production by water electrolysis was carried out. The temperature of the electrolyzer during the test was 60°C.

[0049] Attached Figure 3The electrochemical performance of the electrolyzers assembled with CCM corresponding to Example 1, Example 2, Comparative Example 1 and Comparative Example 2 at 1A / cm2 and 2A / cm2. Regardless of the current density of 1A / cm2 or 2A / cm2, the catalytic layer can show better performance than the comparative example.

[0050] The above implementation modes are merely descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A process for preparing a catalytic layer for hydrogen electrolysis, characterized in that: The following steps are included: S1: Preparation of catalyst slurry: Preparation of cathode catalyst slurry: platinum carbon catalyst, metal oxide, ultrapure water, ion polymer solution and alcohol solution are weighed respectively, and added into a container in sequence, and high-speed shear dispersion is performed under the assistance of ultrasound, and then degassing is performed in a degassing machine; Preparation of anode catalyst slurry: Weigh iridium oxide catalyst, metal oxide, ultrapure water, ion polymer solution and alcohol solution respectively, add them into a container in sequence, and perform high-speed shear dispersion under the assistance of ultrasound; S2: Preparation of catalyst layer: The cathode catalyst slurry and the anode catalyst slurry prepared in step S1 are coated on the transfer base film by blade coating or slit coating, and after drying, the cathode catalyst layer and the anode catalyst layer coated on the base film are obtained; S3: Transfer of catalyst layer: cutting the transfer membranes of the cathode catalyst layer and the anode catalyst layer obtained in step S2 according to the specified size, placing the proton exchange membrane between the cut cathode catalyst layer transfer membrane and the anode catalyst layer transfer membrane, aligning the transfer membranes with the cathode catalyst layer and the anode catalyst layer and performing hot pressing operations to transfer the cathode catalyst layer and the anode catalyst layer to the proton exchange membrane, and obtaining a catalyst coated membrane, i.e., an initial P-CCM; S4: Treatment of the catalytic layer: The catalyst coated membrane obtained in step S3 is immersed in an alkaline solution, washed with deionized water, and then transferred to an acid solution for ion replacement. After the replacement is completed, it is washed with deionized water to obtain a treated catalyst coated membrane, namely T-CCM.

2. The preparation process of a catalytic layer for hydrogen production by electrolysis according to claim 1, characterized in that: When the cathode catalyst slurry is prepared in step S1, the high-speed shear dispersion speed is 10000 rpm and the dispersion time is 1 hour; when the anode catalyst slurry is prepared in step S1, the high-speed shear dispersion speed is 10000 rpm and the dispersion time is 1 hour.

3. The preparation process of a catalytic layer for hydrogen production by electrolysis according to claim 2, characterized in that: In step S3, the hot pressing temperature is 140° C., the hot pressing pressure is 5 MPa, and the hot pressing time is 5 min.

4. The preparation process of a catalytic layer for electrolytic hydrogen production according to claim 3, characterized in that: The metal oxide in step S1 is any one of WO3 and MoO3 or a mixture of two thereof; the ionic polymer solution in step S1 is a perfluorosulfonic acid resin dispersion; the alcohol solution in step S1 is a mixture of any one or more of ethanol, isopropanol, and n-propanol; the alkaline solution in step S4 is a mixture of any one or more of KOH, NaOH, and LiOH; the acid solution in step S4 is a mixture of any one or more of sulfuric acid, nitric acid, acetic acid, and hydrochloric acid.

5. The preparation process of a catalytic layer for hydrogen production by electrolysis according to claim 4, characterized in that: The mass ratio of the metal oxide to the platinum carbon catalyst in step S1 is set to 0-50wt%; the mass ratio of the metal oxide to the iridium oxide catalyst in step S1 is set to 0-10wt%; the solid content of the anode slurry in step S1 is in the range of 10-20wt%, and the solid content of the cathode slurry is in the range of 25-35wt%; the mass ratio of the ion polymer to the platinum carbon catalyst in step S1 is in the range of 0.3-0.5, and the mass ratio of the ion polymer to the iridium oxide catalyst is in the range of 0.1-0.

3.

6. The preparation process of a catalytic layer for hydrogen production by electrolysis according to claim 5, characterized in that: The mass ratio of metal oxide to platinum carbon catalyst in step S1 is set to 5-10wt%; the mass ratio of metal oxide to iridium oxide catalyst in step S1 is set to 2-5wt%; the solid content of anode slurry in step S1 is 15wt%, and the solid content of cathode slurry is 32wt%; the mass ratio of ion polymer to platinum carbon catalyst in step S1 is 0.35, and the mass ratio of ion polymer to iridium oxide catalyst is 0.

15.

7. The preparation process of a catalytic layer for hydrogen production by electrolysis according to claim 4, characterized in that: The metal oxide in step S1 is MoO3; the ionic polymer solution in step S1 is EW790 or EW870 of Solvay; the alcohol solution in step S1 is n-propanol; the alkaline solution in step S4 is NaOH; and the acid solution in step S4 is sulfuric acid.

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