PEM water electrolysis device and preparation process method

Abstract

The invention provides a PEM water electrolysis device. The PEM water electrolysis device specifically comprises a catalyst and an electrolytic bath, the catalyst is nano Pt-M / C particles, and the electrolytic bath is of a multi-layer composite structure prepared by an integrated MEA integration process; wherein the electrolytic cell sequentially comprises an end plate, a sealing sheet, a bipolar plate, a sealing frame, a gas diffusion layer and an electrode plate from outside to inside, and the electrode plate is of a five-in-one or seven-in-one structural membrane electrode structure; m in the nano Pt-M / C particles is Ru, La, Ce, Co and Ni. Meanwhile, the invention further provides a preparation method of the device, the device can be directly installed with an existing mature hydrogen production system in a modularized mode, the fitness degree of renewable energy sources is high, and the product maturity is high.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen production technology and methods, and particularly relates to a PEM water electrolysis device and preparation process. Background Technology

[0002] Hydrogen has an energy density several times higher than other energy sources, and clean energy, represented by hydrogen energy, is expected to account for 56% of the final energy market, potentially triggering a new energy revolution. Among various hydrogen production technologies, PEM (Polymerized Electric Molecular Weight) water electrolysis has become a key technology driving down the cost of green hydrogen due to its advantages of high electrical density, low energy consumption, long lifespan, and ability to operate in low-corrosion environments. It is estimated that if wind / solar curtailment is used for hydrogen production, the cost is close to 15 yuan / kg. Considering the hydrogen price at Shanghai hydrogen refueling stations, PEM electrolysis is economically competitive, and its potential is enormous as the cost of renewable energy decreases.

[0003] However, the current problems in the research and development of PEM electrolysis for hydrogen production include: (1) serious dependence on precious metal catalysts: traditional PEM electrolyzers use IrO2 as the anode catalyst (loading 2-4 mg / cm³). 2 Ir resources are scarce (abundance in the Earth's crust is only 0.000003ppm) and expensive (about $3,000 / gram), which greatly increases the cost of hydrogen production; (2) Insufficient durability of membrane electrodes: under high pressure (3-8MPa) and high electrical density (3A / cm), 2 Under operating conditions, proton exchange membranes (such as Nafion) are susceptible to chemical degradation due to free radical attacks. At the same time, the catalyst layer and membrane interface are delaminated due to the difference in expansion and contraction, and the lifespan is usually <20,000 hours; (3) contradiction between dynamic response and efficiency: when the current density changes rapidly, local concentration polarization will occur at the anode (gas evolution is hindered), resulting in voltage fluctuations (above ±0.3V); while reducing the current density alleviates the polarization, it sacrifices the overall efficiency (voltage >1.8V@1A / cm). 2 ).

[0004] Therefore, developing PEM water electrolysis technology with low precious metal load, long lifespan, and high dynamic response is a key requirement for current industrialization. Summary of the Invention

[0005] Technical Solution: To solve the above-mentioned technical problems, the present invention provides a PEM water electrolysis device, specifically including a catalyst and an electrolyzer; the catalyst is nano-Pt-M / C particles, and the electrolyzer is a multi-layer composite structure prepared by an integrated MEA process; wherein the electrolyzer consists of, from the outside to the inside, an end plate, a sealing sheet, a bipolar plate, a sealing frame, a gas diffusion layer, and an electrode plate, and the electrode plate is either a five-in-one or a seven-in-one membrane electrode structure; in the nano-Pt-M / C particles, M = Ru, La, Ce, Co, Ni.

[0006] As an improvement, the electrode sheet is a five-in-one structured membrane electrode, consisting of a diffusion layer, a catalyst layer, an AEM film, another catalyst layer, and a diffusion layer from top to bottom, wherein the two diffusion layers and the two catalyst layers are made of the same or different materials.

[0007] As an improvement, the end plates of the electrolytic cell are made of titanium or other precious metals, and the overall cell volume is 1-250 Nm. 3 H2 / h,

[0008] As an improvement, the device further includes a diaphragm, which is a blend membrane of sulfonated polyether ether ketone and polybenzimidazole, wherein the mass ratio of sulfonated polyether ether ketone to polybenzimidazole is 5.5-7.5:2.5-4.5, the molecular weight of sulfonated polyether ether ketone is 50,000-80,000, and the molecular weight of polybenzimidazole is 800-1,500.

[0009] As an improvement, a microporous membrane is also included, wherein the microporous membrane is a 10-40 μm thick polytetrafluoroethylene microporous membrane composite on both sides of the diaphragm, and the pore size of the microporous membrane is 0.05-0.35 μm.

[0010] As a specific embodiment of the present invention, a preparation process for a PEM water electrolysis device is also provided, the process comprising:

[0011] (I) Catalyst Preparation

[0012] Step 1.1: Oxidation Treatment

[0013] Add Vulcan XC-72R to concentrated nitric acid, then reflux and stir at 70-95℃ for 1-3 hours. After cooling, wash with deionized water until neutral, and then vacuum dry at 80-90℃ for 10-14 hours.

[0014] Step 1.2: Preparation of metal precursor solution

[0015] Add the oxidized carbon black obtained in step 1.1 to deionized water and ultrasonically disperse it to form a suspension; then add H2PtCl6·6H2O solution to the carbon black suspension and magnetically stir for 10-60 min to form a mixture; then slowly add M salt solution dropwise to the mixture and continue stirring for 1-2 h.

[0016] Step 1.3: Formation of Pt-M / C nanoparticles

[0017] Add 10 mL of 0.1 M NaBH4 solution dropwise to the last solution from step 1.2. Keep the temperature ≤10℃ under ice bath conditions and add the solution at a rate of 0.1-0.75 mL / min. Nitrogen gas is continuously introduced throughout the process at a flow rate of 100-200 mL / min. After completion, continue stirring for 1-2 hours until the solution reaches room temperature.

[0018] Step 1.4: Washing and Drying

[0019] The reaction solution from step 1.3 was centrifuged, washed with deionized water, and precipitated until the conductivity of the filtrate was <50 μS / cm. The precipitate was then dispersed in anhydrous ethanol, ultrasonically dispersed for 10-20 min, and centrifuged again at 6000-8000 rpm for 1-15 min, repeated 1-5 times. The final precipitate was transferred to a vacuum drying oven and dried at 50-75℃ for 8-15 hours at a pressure <100 Pa. After grinding, nano-Pt-M / C catalyst powder was obtained; wherein M = Ru, La, Ce, Co, Ni.

[0020] (II) Preparation of the diaphragm

[0021] Step 2.1: Dissolve sulfonated polyether ether ketone in concentrated sulfuric acid, add polybenzimidazole, and stir at 40-70℃ for 1-5 hours until completely dissolved;

[0022] Step 2.2: Cast the solution from Step 2.1 onto a clean glass plate and dry it at 70-90℃ for 10-15 hours to form a preliminary film;

[0023] Step 2.3: Immerse the initial membrane in 0.5-2.0 mol / L NaOH solution at 40-75℃ for sulfonation treatment for 1-3 hours, wash with water until neutral, and then dry.

[0024] Step 2.4: Pre-stretch the microporous membrane to 1-4 times its original size to cover both sides of the initial membrane, and hot-press it at 100-150℃ and 0.5-1.5MPa for 1-15 minutes to obtain the composite membrane;

[0025] (III) Assembly of the electrolytic cell

[0026] The end plate, sealing sheet, bipolar plate, sealing frame, gas diffusion layer, and electrode plate are installed and assembled in sequence, and the prepared MEA is loaded into the electrode plate at the same time. The electrode plate and MEA are sealed by laser welding to form a single tank. Finally, the supporting system for hydrogen production is installed to complete the assembly.

[0027] Beneficial effects: Compared with existing technologies, the PEM water electrolysis device proposed in this invention includes a nano-Pt-M / C catalyst, a sulfonated polyether ether ketone / polybenzimidazole composite membrane, and an electrolyzer. The nano-Pt-M / C catalyst has a small particle size and concentrated distribution. When used in MEA single-cell testing, its power density can reach 0.48 W / cm² under specific conditions. 2 (@0.6V). Compared with similar catalysts at home and abroad, the current catalyst can still maintain a high power density under conditions of no humidification and low PGM loading, truly achieving the goals of high activity and cost reduction.

[0028] In addition, this invention can be directly and modularly installed with existing mature hydrogen production systems, has high compatibility with renewable energy sources, and has a high degree of product maturity. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the electrolytic cell of the present invention.

[0030] Figure 2 This is a schematic diagram of the microstructure of the catalyst of the present invention.

[0031] Figure 3 This is a bar chart showing the size distribution of the catalyst in this invention.

[0032] In the diagram: End plate 1, sealing sheet 2, bipolar plate 3, sealing frame 4, gas diffusion layer 5, electrode sheet 6. Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] (I) Catalyst Preparation:

[0036] Step 1.1: Add Vulcan XC-72R to concentrated nitric acid, then reflux and stir at 70-95℃ for 1-3 hours. After cooling, wash with deionized water until neutral, and then vacuum dry at 80-90℃ for 10-14 hours.

[0037] Step 1.2: Preparation of metal precursor solution

[0038] Add the oxidized carbon black obtained in step 1.1 to deionized water and ultrasonically disperse it to form a suspension; then add H2PtCl6·6H2O solution to the carbon black suspension and magnetically stir for 10-60 min to form a mixture; then slowly add M salt solution dropwise to the mixture and continue stirring for 1-2 h.

[0039] Step 1.3: Formation of Pt-M / C nanoparticles

[0040] Add 10 mL of 0.1 M NaBH4 solution dropwise to the last solution from step 1.2. Keep the temperature ≤10℃ under ice bath conditions and add the solution at a rate of 0.1-0.75 mL / min. Nitrogen gas is continuously introduced throughout the process at a flow rate of 100-200 mL / min. After completion, continue stirring for 1-2 hours until the solution reaches room temperature.

[0041] Step 1.4: Washing and Drying

[0042] The reaction solution from step 1.3 was centrifuged, washed with deionized water, and precipitated until the conductivity of the filtrate was <50 μS / cm. The precipitate was then dispersed in anhydrous ethanol, ultrasonically dispersed for 10-20 min, and centrifuged again at 6000-8000 rpm for 1-15 min, repeated 1-5 times. The final precipitate was transferred to a vacuum drying oven and dried at 50-75℃ for 8-15 hours (pressure <100 Pa). After grinding, nano-Pt-M / C catalyst powder was obtained; wherein M = Ru, La, Ce, Co, Ni.

[0043] (II) Preparation of the diaphragm

[0044] Step 2.1: Dissolve sulfonated polyether ether ketone in concentrated sulfuric acid, add polybenzimidazole, and stir at 40-70℃ for 1-5 hours until completely dissolved;

[0045] Step 2.2: Cast the solution from Step 2.1 onto a clean glass plate and dry it at 70-90℃ for 10-15 hours to form a preliminary film;

[0046] Step 2.3: Immerse the initial membrane in 0.5-2.0 mol / L NaOH solution at 40-75℃ for sulfonation treatment for 1-3 hours, wash with water until neutral, and then dry.

[0047] Step 2.4: Pre-stretch the microporous membrane to 1-4 times its original size to cover both sides of the initial membrane, and hot-press it at 100-150℃ and 0.5-1.5MPa for 1-15 minutes to obtain the composite membrane;

[0048] (III) Assembly of the electrolytic cell

[0049] The components are assembled sequentially: end plate 1, sealing sheet 2, bipolar plate 3, sealing frame 4, gas diffusion layer 5, and electrode plate 6. Simultaneously, the prepared MEA is loaded into the electrode plate, with the electrode plate and MEA sealed by laser welding. This forms a single tank. Finally, the hydrogen production system is installed, completing the assembly. The hydrogen production system is an existing, mature system; no specific model or type is limited. Any system that implements the technical solution of this application is within the scope of protection of this invention.

[0050] The invention will be further illustrated below through performance testing experiments.

[0051] 1. Performance comparison tests were conducted between the catalyst of this invention and similar products.

[0052] Table 1 shows a comparison of the performance of the present invention with that of existing technologies.

[0053]

[0054] Compared with similar products at home and abroad, the electrolyzed water in Example 1 above has a very high power density under the conditions of no humidification and low PGM load, truly achieving the goals of high activity and cost reduction.

[0055] Furthermore, the microstructure and average particle size of the nano-Pt-M / C catalyst prepared in this invention were analyzed. It was found that the average particle size of the catalyst can reach 3 nm, and the distribution is concentrated. Figure 3 As shown. It should be noted that when this invention is used for single-cell testing in MEA, the power density can reach 0.48 W / cm². 2 (@0.6V).

[0056] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A PEM electrolysis water device, characterized in that: It includes a catalyst and an electrolytic cell; the catalyst is nano-Pt-M / C particles, and the electrolytic cell is a multi-layer composite structure prepared by an integrated MEA process; wherein the electrolytic cell consists of an end plate (1), a sealing sheet (2), a bipolar plate (3), a sealing frame (4), a gas diffusion layer (5), and an electrode sheet (6) from the outside to the inside, and the electrode sheet (6) is a membrane electrode structure of either a five-in-one or a seven-in-one structure; M in the nano-Pt-M / C particles is Ru, La, Ce, Co, or Ni.

2. The PEM water electrolysis device according to claim 1, characterized in that: The electrode sheet (6) is a five-in-one structured membrane electrode, consisting of a diffusion layer, a catalyst layer, an AEM membrane, a catalyst layer, and a diffusion layer from top to bottom. The two diffusion layers and the two catalyst layers are made of the same or different materials.

3. The PEM electrolysis water device according to claim 1, characterized in that: The end plate (1) of the electrolytic cell is made of titanium or a precious metal, and the overall cell size is 1-250 Nm. 3 H2 / h.

4. The PEM water electrolysis device according to claim 1, characterized in that: The device further includes a diaphragm, which is a blend membrane of sulfonated polyether ether ketone and polybenzimidazole, wherein the mass ratio of sulfonated polyether ether ketone to polybenzimidazole is 5.5-7.5:2.5-4.5, the molecular weight of sulfonated polyether ether ketone is 50,000-80,000, and the molecular weight of polybenzimidazole is 800-1,500.

5. The PEM water electrolysis device according to claim 4, characterized in that: It also includes a microporous membrane, which is a 10-40 μm thick polytetrafluoroethylene microporous membrane composite on both sides of the diaphragm, with a pore size of 0.05-0.35 μm.

6. A preparation process for a PEM water electrolysis device, characterized in that: (I) Catalyst Preparation Step 1.1: Oxidation Treatment Add Vulcan XC-72R to concentrated nitric acid, then reflux and stir at 70-95℃ for 1-3 hours. After cooling, wash with deionized water until neutral, and then vacuum dry at 80-90℃ for 10-14 hours. Step 1.2: Preparation of metal precursor solution Add the oxidized carbon black obtained in step 1.1 to deionized water and ultrasonically disperse it to form a suspension; then add H2PtCl6·6H2O solution to the carbon black suspension and magnetically stir for 10-60 min to form a mixture; then slowly add M salt solution dropwise to the mixture and continue stirring for 1-2 h. Step 1.3: Formation of Pt-M / C nanoparticles Add 10 mL of 0.1 M NaBH4 solution dropwise to the last solution from step 1.

2. Keep the temperature ≤10℃ under ice bath conditions and add the solution at a rate of 0.1-0.75 mL / min. Nitrogen gas is continuously introduced throughout the process at a flow rate of 100-200 mL / min. After completion, continue stirring for 1-2 hours until the solution reaches room temperature. Step 1.4 Washing and Drying The reaction solution from step 1.3 was centrifuged, washed with deionized water, and precipitated until the conductivity of the filtrate was <50 μS / cm. The precipitate was then dispersed in anhydrous ethanol, ultrasonically dispersed for 10-20 min, and centrifuged again at 6000-8000 rpm for 1-15 min, repeated 1-5 times. The final precipitate was transferred to a vacuum drying oven and dried at 50-75℃ for 8-15 hours (pressure <100 Pa). After grinding, nano-Pt-M / C catalyst powder was obtained; wherein M = Ru, La, Ce, Co, Ni. (II) Preparation of the diaphragm Step 2.1: Dissolve sulfonated polyether ether ketone in concentrated sulfuric acid, add polybenzimidazole, and stir at 40-70℃ for 1-5 hours until completely dissolved; Step 2.2: Cast the solution from Step 2.1 onto a clean glass plate and dry it at 70-90℃ for 10-15 hours to form a preliminary film; Step 2.3: Immerse the preliminary film in 0.5-2.0 mol / L NaOH solution at 40-75℃ for sulfonation treatment for 1-3 hours, wash with water until neutral, and then dry. Step 2.4: Pre-stretch the microporous membrane to 1-4 times its original size to cover both sides of the initial membrane, and hot-press it at 100-150℃ and 0.5-1.5MPa for 1-15 minutes to obtain the composite membrane; (III) Assembly of the electrolytic cell The end plate (1), sealing sheet (2), bipolar plate (3), sealing frame (4), gas diffusion layer (5), and electrode plate (6) are installed and assembled in sequence, and the prepared MEA is simultaneously loaded into the electrode plate. The electrode plate and MEA are sealed by laser welding to form a single tank. Finally, the supporting system for hydrogen production is installed to complete the assembly.

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