High-efficiency proton exchange membrane against carbon monoxide poisoning and preparation method thereof

Abstract

The present application relates to the technical field of fuel cell, and particularly relates to a high-efficiency proton exchange membrane against carbon monoxide poisoning and a preparation method thereof.The present application adopts a graphene functionalized anchor catalyst and a gradient catalyst distribution membrane structure design strategy, improves the dispersity and utilization rate of the catalyst in the proton membrane, and then effectively relieves the performance attenuation of the stack caused by the gas impurities, and guides the optimization iteration of the membrane electrode and the stack.The present application prepares the proton exchange membrane with excellent anti-carbon monoxide poisoning effect, and the membrane electrode prepared by using the proton exchange membrane is used in the fuel cell, compared with the proton exchange membrane without the additive, the performance of the cell based on the membrane is greatly improved, the anti-carbon monoxide poisoning capacity can reach 0.72V@600mA / cm 2 @60ppm CO, and the durability of the fuel cell is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a highly efficient proton exchange membrane resistant to carbon monoxide poisoning and its preparation method. Background Technology

[0002] A fuel cell is an energy conversion device that generates electricity through an electrochemical reaction between hydrogen and oxygen. Its reaction product is only water, achieving true pollution-free and zero-emission operation. However, gaseous impurities, such as carbon monoxide, that may be present in the feed gas can poison the catalyst, hindering hydrogen adsorption and the subsequent electrochemical oxidation process, resulting in a significant decrease in battery performance.

[0003] To address this issue, current research primarily focuses on the design and preparation of catalysts resistant to carbon monoxide poisoning, such as doping catalysts with elements like Ru, Mo, W, and Sn to reduce the impact of CO. However, existing technologies have not paid much attention to the dispersion of gaseous impurities like carbon monoxide in the proton exchange membrane. The entry of these impurities into the proton exchange membrane can also cause performance degradation in the fuel cell stack, leading to a significant decrease in battery performance. Summary of the Invention

[0004] In view of this, the present invention provides a highly efficient proton exchange membrane resistant to carbon monoxide poisoning and its preparation method. The present invention adopts a gradient distribution membrane structure design and graphene functionalized anchoring catalyst to improve the dispersion uniformity of the carbon monoxide poisoning resistant catalyst in the proton exchange membrane, improve the ability of the proton exchange membrane to resist gaseous impurity poisoning, and lay the foundation for the optimization and iteration of membrane electrode and stack.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a highly efficient proton exchange membrane for resisting carbon monoxide poisoning, the proton exchange membrane being composed of an additive layer and a fluorine-containing proton exchange membrane;

[0007] The additive layer is a fluorinated resin layer containing graphene oxide and a carbon monoxide poisoning resistance catalyst (GO-M), wherein the graphene oxide and the carbon monoxide poisoning resistance catalyst exist in a blended manner or in a layer-by-layer stacked manner.

[0008] The additive layers are located on both sides of the fluorine-containing proton exchange membrane, and the contents of graphene oxide and the anti-carbon monoxide poisoning catalyst are distributed in a gradient.

[0009] Furthermore, the graphene oxide (GO) is obtained by directly preparing graphene oxide powder using the Hummers method or by preparing graphene films using chemical vapor deposition (CVD) followed by oxidation. Graphene oxide contains anchoring groups, such as epoxy groups (COC), hydroxyl groups (-OH), carboxyl groups (-COOH), and carbonyl groups (C=O). The oxygen-containing functional groups of graphene oxide enhance the dispersibility and stability of the catalyst through anchoring effects (coordination, hydrogen bonding, or electrostatic interactions, etc.), and alleviate CO poisoning through electronic effects and interfacial synergistic effects.

[0010] Oxygen-containing functional groups can serve as anchoring sites for metal nanoparticles, binding to the active components of the catalyst (such as Pt and Ru) through chemical bonds (e.g., coordination bonds, hydrogen bonds) or electrostatic interactions, inhibiting the aggregation of metal particles and achieving highly uniform dispersion. Uniformly dispersed catalysts expose more active sites, improving the utilization rate of reactive surfaces and enhancing the catalytic efficiency of CO and hydrogen oxidation. The strong interaction between functional groups and metal particles prevents catalyst migration or detachment during operation, maintaining long-term stability, especially under the dynamic operating conditions of fuel cells. The anchoring effect reduces sintering of metal particles at high temperatures or high potentials, maintaining the nanoscale active structure of the catalyst. Oxygen-containing functional groups (such as carboxyl and hydroxyl groups) have strong electron-withdrawing properties, which can regulate the electronic state of the supported metal, weakening the adsorption strength of CO on the Pt surface (reducing the CO adsorption energy), thereby reducing CO poisoning. For Pt / Ru alloy catalysts, the electronic effect of GO can synergize with the "bifunctional mechanism" of Ru, further enhancing the resistance to CO poisoning. The hydroxyl and carboxyl groups on the surface of GO can serve as proton sources, accelerating the oxidation of CO to CO2 and reducing the accumulation of CO on the catalyst surface. The high conductivity of graphene oxide can promote electron transfer and enhance the CO oxidation kinetics.

[0011] Furthermore, the anti-carbon monoxide poisoning catalyst is a single metal, alloy, supported single metal or supported alloy containing a catalytically active component, and the catalytically active component is selected from Pt, Ru, Rh, Pd, Mo; preferably Pt, Ru and Pt / Ru alloy.

[0012] Furthermore, the support for the supported single metal or supported alloy is at least one of carbon, silicon oxide, aluminum oxide, and titanium oxide; preferably, a carbon support.

[0013] Furthermore, the total thickness of the proton exchange membrane for resisting carbon monoxide poisoning is 8 μm-40 μm; preferably 12 μm-17 μm. If the total thickness of the proton exchange membrane is too thin, it will lead to insufficient mechanical strength, increased gas permeation, and decreased durability; if it is too thick, it will lead to increased proton conduction resistance, increased volume and weight, and increased cost.

[0014] Furthermore, the thickness of the additive layer is 1 μm-10 μm, preferably 2 μm-5 μm. If the additive layer is too thin, it will result in insufficient CO resistance and weak interfacial bonding; if it is too thick, it will result in impaired proton conduction, increased mechanical brittleness, and increased cost and process complexity.

[0015] Furthermore, the thickness of the fluorinated proton exchange membrane is 6 μm-20 μm, preferably 8 μm-15 μm. If the fluorinated proton exchange membrane is too thin, the base membrane function will be weakened. As the main body for proton conduction, if the fluorinated membrane is too thin, its intrinsic ion channel network will be incomplete, leading to a decrease in proton conductivity; insufficient support will make it difficult to effectively support the additive layers on both sides, potentially causing membrane structure deformation or interlayer separation; excessive thickness will result in resource waste and high cost of fluorinated materials.

[0016] Furthermore, the mass ratio of GO-M to fluorinated resin in the additive layer is 0.01-10, preferably 0.4-5.

[0017] A low mass ratio of GO-M to fluorinated resin in the additive layer leads to insufficient CO resistance. Insufficient GO-M content results in insufficient active sites for the catalyst, hindering effective CO oxidation and increasing the risk of CO poisoning on the membrane surface. The gradient effect is weakened, with sparse GO-M distribution making it difficult to form a CO removal gradient from the membrane surface to the interior, thus reducing overall anti-poisoning efficiency. Conversely, an excessively high ratio hinders proton conduction. When the proportion of fluorinated resin is too low, its proton transport channels (such as sulfonic acid groups) are covered by GO-M, significantly reducing the overall proton conductivity of the membrane. Mechanical properties deteriorate; insufficient resin content increases membrane brittleness, making it prone to breakage or delamination. Interfacial adhesion decreases; excessive GO-M may impede the compatibility between the additive layer and the fluorinated base membrane, leading to interlayer delamination.

[0018] Furthermore, the mass ratio of M to GO in GO-M is 0.01-10.0%, preferably 0.2-5.0%. A low mass ratio of M to GO in GO-M can lead to insufficient catalytic activity, low metal loading, insufficient active sites, and an inability to meet actual CO oxidation rate requirements. Furthermore, the lack of synergistic effect weakens the electronic regulation between the anchoring groups of GO and the metal, making it difficult to effectively reduce CO adsorption intensity.

[0019] In GO-M, an excessively high mass ratio of M to GO can cause metal particle agglomeration. Excess metal cannot be effectively anchored by GO, leading to nanoparticle agglomeration and a reduction in specific surface area. Furthermore, the GO carrier is overloaded, with the surface functional groups of GO being excessively occupied by the metal, weakening its ability to assist in proton transport (such as the proton hopping effect of hydroxyl groups). At the same time, the increased use of precious metals (such as Pt and Ru) significantly increases material costs and reduces economic efficiency.

[0020] Furthermore, the GO-M content in the monolayer additive layer is distributed in a gradient with a thickness interval of 0.2 μm-0.5 μm, and the mass ratio of GO-M to fluorinated resin varies from 0.002 to 0.005, showing an increasing trend from the middle to both sides.

[0021] The gradient distribution, which increases from the middle to both sides, can match the CO diffusion path, achieving strong resistance to CO poisoning in the outer layer and high proton conduction in the inner layer; at the same time, it ensures catalytic activity, proton conduction, mechanical stability and cost-effectiveness.

[0022] During fuel cell operation, CO permeates from the membrane surface into the interior. A gradient distribution results in the highest GO-M content on the surface, preferentially oxidizing surface CO and forming a "dense on the outside, sparse on the inside" scavenging network. This network progressively intercepts CO molecules, preventing them from penetrating deeper into the membrane. The increasing GO-M concentration gradient matches the CO oxidation reaction rate requirements (higher surface reaction rates are needed), avoiding localized catalyst overload or waste. The outer layers near the membrane sides preferentially undertake CO oxidation, sacrificing a small amount of proton conductivity. However, through a gradient decreasing design, the proportion of fluorinated resin inside gradually increases, maintaining the overall membrane proton conductivity. Avoiding abrupt interfacial pressure drops and using gradual intervals smoothly transitions proton migration resistance between different regions, reducing interfacial polarization losses caused by abrupt compositional changes. The gradient mass ratio reduces the difference in the coefficients of thermal expansion between layers, lowering internal stress during humidity changes and preventing delamination or cracking. The oxygen-containing groups of GO form a progressive hydrogen bond network with the sulfonic acid groups of fluorinated resins in a gradient distribution, which strengthens the interlayer bonding strength. Noble metals are concentrated only in the surface areas where high activity is required, reducing the loading of M inside, reducing the overall catalyst dosage and saving costs. At the same time, the gradient distribution avoids excessively high local metal concentrations, and combined with the anchoring effect of GO, ensures the dispersion of nanoparticles.

[0023] The fluorinated proton exchange membrane can be obtained by purchasing or by preparing it according to existing methods. It can be a non-reinforced membrane (i.e., a homogeneous membrane) of fluorinated proton exchange resin or a reinforced membrane (i.e., a reinforced membrane) of fluorinated proton exchange resin. The fluorinated proton exchange resin reinforced membrane is composed of a fluorinated resin layer and a reinforcing layer, which are alternately stacked together, and both outer sides are fluorinated resin layers. The fluorinated proton exchange resin non-reinforced membrane is a homogeneous membrane prepared with fluorinated resin and without reinforcing materials.

[0024] The fluorinated proton exchange membrane is prepared by using a purchased resin dispersion and methods such as spraying, spin coating, or blade coating.

[0025] In a second aspect, the present invention provides a method for preparing the proton exchange membrane described in the first aspect, wherein when the additive layer contains graphene oxide and an anti-carbon monoxide poisoning catalyst in a blended manner, the method includes the following steps:

[0026] Graphene oxide powder and carbon monoxide poisoning resistance catalyst are first dispersed in an organic solvent, then mixed with a resin dispersion, coated onto a fluorine-containing proton exchange membrane, and dried to form the final product.

[0027] Furthermore, the dispersion process is one or more of magnetic stirring, ultrasonic dispersion, ball milling, high-pressure homogenization, or microjet, with ultrasonic dispersion being preferred.

[0028] Furthermore, the ultrasonic dispersion power is 100~800 W, the ultrasonic time is 10~60 minutes, and the operation is intermittent, with 1-10 seconds of operation and 1-10 seconds of pause. The preferred power is 200~400 W, the ultrasonic time is 15~30 minutes, and the operation is intermittent, with 2-5 seconds of operation and 2-5 seconds of pause.

[0029] Further, the organic solvent is one or more of water, alcohols, N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC) or N-methylpyrrolidone (NMP), preferably water, ethanol, N,N-dimethylformamide (DMF) or N-methylpyrrolidone (NMP).

[0030] Furthermore, the coating method includes spraying, spin coating, blade coating, or inkjet printing.

[0031] Furthermore, the drying and forming process is a vacuum heating drying process with a vacuum degree of -0.1 MPa and a temperature control of (40-60)℃-(70-100)℃-(110-140)℃, with each segment lasting 3-15 min. Preferably, the temperature control is (50-60)℃-(90-100)℃-(130-140)℃, with each segment lasting 5-8 min.

[0032] The following can be achieved by three-stage heating (low temperature → medium temperature → high temperature): (1) solvent removal in stages, matching the boiling point differences of different solvents, avoiding rapid volatilization that leads to membrane structure defects; (2) resin progressive curing, controlling the relaxation and cross-linking dynamics of fluorinated resin molecular chains, and optimizing proton channel formation; (3) interfacial stress release, reducing the difference in thermal expansion coefficients between the additive layer and the base film, and preventing interlayer peeling.

[0033] Thirdly, the present invention provides a method for preparing the proton exchange membrane described in the first aspect, wherein the additive layer contains graphene oxide and an anti-carbon monoxide poisoning catalyst in a layer-by-layer stacked manner, comprising the following steps:

[0034] Graphene films are transferred onto fluorine-containing proton exchange membranes using a wet process, followed by oxidation treatment using oxygen plasma. A dispersion containing a catalyst for resisting carbon monoxide poisoning and a resin dispersion are mixed and coated onto the proton exchange membrane containing graphene oxide. The mixture is then dried and shaped. This process is repeated until the last layer is coated and then dried.

[0035] Furthermore, the wet process is a wet chemical process assisted by polymethyl methacrylate (PMMA).

[0036] Further, the oxygen plasma (O2Plasma) oxidation treatment has the following parameters: power: 20~100 W, time: 1~10 minutes, gas flow rate (O2): 5~100 sccm, gas pressure: 10~100 mTorr; preferably, power: 50~80 W, time: 3~5 minutes, gas flow rate (O2): 10~50 sccm, gas pressure: 30~60 mTorr.

[0037] Oxygen plasma bombards the graphene surface with high-energy active oxygen species, controllably introducing anchoring groups such as epoxy (COC), hydroxyl (-OH), and carboxyl (-COOH) groups, providing chemical binding sites for subsequent catalyst loading. Oxygen plasma can decompose the PMMA support layer remaining from wet transfer, preventing organic impurities from hindering the interfacial bonding between GO and fluorinated resins. Plasma etching creates a nanoscale rough structure, enhancing the mechanical interlocking effect between the fluorinated resin and GO, and improving the bonding strength.

[0038] Furthermore, the dispersion process of the dispersion containing the anti-carbon monoxide poisoning catalyst is one or more of magnetic stirring, ultrasonic dispersion, ball milling, high-pressure homogenization, or microfluidization, with ultrasonic dispersion being preferred.

[0039] Furthermore, the ultrasonic dispersion power is 100~800 W, the ultrasonic time is 10~60 minutes, and the operation is intermittent, with 1-10 seconds of operation and 1-10 seconds of pause. The preferred power is 200~400 W, the ultrasonic time is 15~30 minutes, and the operation is intermittent, with 2-5 seconds of operation and 2-5 seconds of pause.

[0040] Furthermore, in the dispersion containing the catalyst for resisting carbon monoxide poisoning, the solvent is one or more of water, alcohol, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone; preferably water, ethanol, N,N-dimethylformamide, or N-methylpyrrolidone.

[0041] Furthermore, the drying and forming process is a vacuum heating drying process with a vacuum degree of -0.1 MPa and a temperature control of (40-60)℃-(70-100)℃-(110-140)℃, with each segment lasting 3-15 min. Preferably, the temperature control is (50-60)℃-(90-100)℃-(130-140)℃, with each segment lasting 5-8 min.

[0042] Furthermore, when the graphene oxide and carbon monoxide poisoning resistance catalyst in the additive layer are stacked layer by layer, after each layer is coated, the process of introducing graphene oxide into the fluorine-containing proton exchange membrane is repeated after vacuum heating and drying to ensure the mass ratio of graphene oxide and carbon monoxide poisoning resistance catalyst, as well as the mass ratio of additive GO-M and fluorine-containing resin. After the last layer is coated, the process is completed by vacuum heating and drying.

[0043] Thirdly, the present invention provides a membrane electrode comprising the proton exchange membrane described in the first aspect.

[0044] Furthermore, the membrane electrode also includes an anode plate, a cathode plate, an anode diffusion layer, a cathode diffusion layer, an anode catalyst, and a cathode catalyst.

[0045] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0046] This invention proposes for the first time a strategy combining functionalized graphene-anchored carbon monoxide poisoning-resistant catalysts with a gradient distribution membrane structure design. The catalyst is introduced into the proton exchange membrane through blending or layer-by-layer stacking. Utilizing the synergistic effect of multiple functional groups in functionalized graphene, the catalyst is anchored through physical adsorption and chemical bonding. The ordered porous structure of graphene facilitates catalyst dispersion, while the gradient distribution structure further improves its utilization rate. This invention produces a proton exchange membrane with excellent carbon monoxide poisoning resistance. When fabricated as a membrane electrode assembly (MEA) for fuel cells, the battery performance based on this membrane is significantly improved compared to additive-free proton exchange membranes, achieving a carbon monoxide poisoning resistance of 0.72V@600mA / cm. 2 @60ppm CO, with a maximum improvement rate of 1.88 times, effectively improving the durability of fuel cells. Attached Figure Description

[0047] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0048] Figure 1 This is a schematic diagram of the proton exchange membrane structure for resisting carbon monoxide poisoning prepared by blending in Embodiment 2 of the present invention;

[0049] Figure 2 This is a schematic diagram of the proton exchange membrane structure for carbon monoxide poisoning prepared by stacking in Embodiment 3 of the present invention;

[0050] Figure 3 This is the Raman spectrum of the graphene oxide obtained after treatment in Example 3;

[0051] Figure 4 This is a schematic diagram of the membrane electrode structure prepared based on the proton exchange membrane for carbon monoxide poisoning according to the present invention;

[0052] Figure 5 These are polarization curves of the proton exchange membranes prepared in Examples 1-3 and Comparative Examples 1-2, used in carbon monoxide poisoning tests.

[0053] 1-Anti-carbon monoxide poisoning catalyst; 2-Graphene oxide; 3-Additive layer; 4-Fluoropolymer layer; 5-Reinforcing layer; 6-Fluoropolymer proton exchange membrane; 7-Anti-carbon monoxide poisoning proton exchange membrane; 8-Cathode / anode catalyst; 9-Cathode / anode diffusion layer; 10-Cathode / anode plate. Detailed Implementation

[0054] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0055] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0056] Example 1:

[0057] (1) Add 1 g of graphite powder and 0.5 g of NaNO3 to 23 mL of concentrated H2SO4 and stir in an ice bath for 15 minutes; slowly add 3 g of KMnO4 (in 5 portions, 5 minutes apart) and stir for 2 hours. Remove the ice bath and stir in an oil bath at 35 ℃ for 1 hour to form a paste. Slowly add 46 mL of deionized water and heat to 95 ℃ and stir for 15 minutes. Add 140 mL of deionized water to dilute, and then add 5 mL of H2O2 dropwise until the solution turns bright yellow. Wash three times with 5% HCl (2000 rpm, 10 minutes each time) to remove impurity ions. Then wash with deionized water until pH ≈ 5~6. The product is placed in a dialysis bag (molecular weight cutoff 8000~14000), dialyzed for 3~5 days until pH ≈ 7, and vacuum dried at 60 ℃ for 12 hours to obtain graphene oxide (GO) powder.

[0058] (2) 1 g GO powder, 2 mg of purchased Pt / Ru catalyst and 20 mL ethanol were ultrasonically dispersed at room temperature for 30 minutes with a power of 200 W and intermittent operation, working for 2 seconds and pausing for 2 seconds to obtain GO-M dispersion, wherein the mass ratio of M (Pt / Ru catalyst) to GO was 0.2%.

[0059] (3) Disperse the fluorosulfonic acid resin (Chemours (formerly DuPont) Nafion) TMD2020 was directly coated and dried to form a film. The vacuum degree was -0.1 MPa, the temperature was controlled at 60 ℃ - 100 ℃ - 130 ℃, and each segment lasted for 5 min. The thickness of the unreinforced fluorinated proton exchange resin film was 8 μm.

[0060] (4) Take different amounts of fluorinated resin dispersion (Chemours (formerly DuPont) Nafion) TM The D520 and GO-M dispersions were mixed evenly, with the mass ratio of GO-M to fluorinated resin being 0.4 (initial value). Then, an additive layer was prepared on both sides of the non-reinforced fluorinated proton exchange resin membrane obtained in step 3 using a scraping method. The additive layer thickness was 2 μm, with thickness intervals of 0.2 μm. The mass ratio of GO-M to fluorinated resin increased by 0.002 from the center to both sides (i.e., 0.400, 0.402, 0.404, 0.406, 0.408, 0.410, 0.412, 0.414, 0.416, 0.418, 0.420). Finally, the membrane was vacuum-dried and shaped under vacuum of -0.1 MPa at a temperature controlled at 60 ℃ - 100 ℃ - 130 ℃ for 5 min per interval. The total thickness of the resulting proton exchange membrane resistant to carbon monoxide poisoning was 12 μm.

[0061] Example 2:

[0062] (1) Add 1 g of graphite powder and 0.5 g of NaNO3 to 23 mL of concentrated H2SO4 and stir in an ice bath for 15 minutes; slowly add 3 g of KMnO4 (in 5 portions, 5 minutes apart) and stir for 2 hours. Remove the ice bath and stir in an oil bath at 35 ℃ for 1 hour to form a paste. Slowly add 46 mL of deionized water and heat to 95 ℃ and stir for 15 minutes. Add 140 mL of deionized water to dilute, and then add 5 mL of H2O2 dropwise until the solution turns bright yellow. Wash three times with 5% HCl (2000 rpm, 10 minutes each time) to remove impurity ions. Then wash with deionized water until pH ≈ 5~6. The product is placed in a dialysis bag (molecular weight cutoff 8000~14000), dialyzed for 3~5 days until pH ≈ 7, and vacuum dried at 60 ℃ for 12 hours to obtain GO powder.

[0063] (2) 1 g GO powder, 4 mg of purchased PtRu / C catalyst and 30 mL DMF were ultrasonically dispersed at room temperature for 30 minutes with a power of 400 W and intermittent operation, working for 2 seconds and pausing for 2 seconds to obtain GO-M dispersion, wherein the mass ratio of M to GO was 0.4%.

[0064] (3) Take different amounts of fluorinated resin dispersion (Chemours (formerly DuPont) Nafion)TM D520) and GO-M dispersion were mixed evenly, with the mass ratio of GO-M to fluorinated resin being 1 (initial value). Then, the mixture was applied using a blade coating method onto a purchased fluorinated proton exchange resin reinforced membrane (12 μm, Gore-SELECT). ® Additive layers were prepared on both sides of M788.12, with an additive layer thickness of 1 μm. The thickness of each additive layer was 0.2 μm, and the mass ratio of GO-M and fluorinated resin increased by 0.004 from the middle to both sides (i.e., 1.000, 1.004, 1.008, 1.012, 1.016, 1.020). Finally, the membrane was dried under vacuum at a vacuum degree of -0.1 MPa and a temperature controlled at 50 ℃ - 70 ℃ - 140 ℃, with each segment lasting 8 min. The total thickness of the proton exchange membrane resistant to carbon monoxide poisoning was 14 μm.

[0065] A schematic diagram of the proton exchange membrane structure prepared in this embodiment is shown below. Figure 1 As shown, (1) is a catalyst against carbon monoxide poisoning, (2) is graphene oxide, (3) is an additive layer, (4) is a fluorinated resin layer, (5) is a reinforcing layer, and (6) is a fluorinated proton exchange membrane.

[0066] Example 3:

[0067] (1) Spin-coat the PMMA solution onto a purchased chemical vapor deposition (CVD) graphene film (approximately 1 g, WJCDS / F from Hefei Microcrystalline) at 3000 rpm for 30 seconds. Heat at 90-100 °C for 1-2 minutes to remove the solvent. Float the PMMA / graphene sample on the surface of a 0.1 M ammonium persulfate etching solution until the metal is completely dissolved. Transfer to deionized water three times, 5 minutes each time, to remove residual etching solution. Transfer to a purchased fluorinated proton exchange resin reinforced membrane (15 μm, GORE-SELECT from Gore). ® On M775.15), it was left to stand at room temperature for 12 hours. Then, it was soaked in acetone at room temperature for 2-4 hours to remove PDMMA. The graphene on the surface of the enhanced proton exchange membrane was oxidized using oxygen plasma (O2 Plasma) at a power of 80W for 5 minutes, a gas flow rate (O2) of 10 sccm, and a gas pressure of 30 mTorr. The mass of the GO-containing proton exchange membrane was obtained by subtracting the mass of the proton exchange membrane from the mass of the GO-containing proton exchange membrane, which was 1.1g.

[0068] (2) 22 mg of purchased Pt / C catalyst and 80 mL of ethanol were ultrasonically dispersed at room temperature for 30 minutes with a power of 800 W and intermittent operation, working for 5 seconds and pausing for 5 seconds to obtain catalyst (M) dispersion, wherein the mass ratio of M to GO was 2%.

[0069] (3) Take different amounts of fluorinated resin dispersion (Chemours (formerly DuPont) Nafion) TM D520) and M dispersion are mixed evenly, with the mass ratio of GO-M to fluorinated resin being 5 (initial value). Then, an additive layer is prepared on both sides of the GO-containing proton exchange membrane (15 μm) obtained in step 1 using a scraping method. The additive layer thickness is 1 μm, with the mass ratio of GO-M to fluorinated resin increasing by 0.005 from the center to both sides at 0.2 μm thickness intervals (i.e., 5.000, 5.005, 5.010, 5.015, 5.020, 5.025). Note that after each 0.2 μm additive layer is scraped and vacuum-dried, step 1 needs to be repeated to introduce the GO layer, while ensuring that the mass ratio of M to GO is 2% and the mass ratio of GO-M to fluorinated resin increases by 0.005. After the last 0.2 μm additive layer is scraped, vacuum-dried. The vacuum heating parameters mentioned in this step are: vacuum degree -0.1 MPa, temperature control 40 ℃ - 90 ℃ - 110 ℃. The temperature was set at ℃, and each segment lasted for 8 minutes; the final total thickness of the proton exchange membrane for resisting carbon monoxide poisoning was 17 μm.

[0070] A schematic diagram of the proton exchange membrane structure prepared in this embodiment is shown below. Figure 2 As shown. (1) is an anti-carbon monoxide poisoning catalyst, (2) is graphene oxide, (3) is an additive layer, (4) is a fluorinated resin layer, (5) is a reinforcing layer, and (6) is a fluorinated proton exchange membrane. The Raman spectrum of the graphene oxide prepared in this embodiment is shown below. Figure 3 As shown.

[0071] Comparative Example 1:

[0072] The purchased fluorosulfonic acid resin dispersion (Chemours (formerly DuPont) Nafion) TM D2020), directly coated into a film and dried, with a vacuum degree of -0.1 MPa, temperature control of 60 ℃ - 100 ℃ - 130 ℃, each segment lasting 5 min, and a film thickness of 12 μm.

[0073] Comparative Example 2:

[0074] (1) 4 mg of purchased PtRu / C catalyst and 10 mL of DMF were ultrasonically dispersed at room temperature for 30 minutes with a power of 400 W and intermittent operation, working for 2 seconds and pausing for 2 seconds, to obtain catalyst (M) dispersion;

[0075] (2) Take different amounts of fluorinated resin dispersion (Chemours (formerly DuPont) Nafion) TMD520) and M dispersion were mixed evenly, wherein the mass ratio of M to fluorinated resin was 1:1. Then, the mixture was applied by a blade coating method onto a 12 μm fluorinated proton exchange resin reinforced membrane (GORE-SELECT, Gore). ® Additive layers were prepared on both sides of M788.12, with an additive layer thickness of 1 μm. Finally, the membrane was dried under vacuum with a vacuum degree of -0.1 MPa and a temperature control of 50 ℃ - 70 ℃ - 140 ℃ for 8 min per segment. The total thickness of the resulting proton exchange membrane was 14 μm.

[0076] The proton exchange membranes prepared in Examples 1-3 and Comparative Examples 1-2 were assembled into membrane electrodes for electrochemical performance testing. The membrane electrode structure is as follows: Figure 4 As shown, (7) is a proton exchange membrane resistant to carbon monoxide poisoning; (8) is an anion / anode catalyst; (9) is an anion / anode diffusion layer; and (10) is an anion / anode plate. The platinum loading of the catalyst layer is 0.5 mg / cm². 2 The test conditions were 75 °C - 40% RH, hydrogen (containing CO) - air atmosphere, and the results are shown in Table 1 and... Figure 5 As shown.

[0077] Table 1. Comparison of the carbon monoxide poisoning resistance of proton exchange membranes prepared with different parameters.

[0078]

[0079] Figure 5 These are polarization curves of the proton exchange membranes prepared in Examples 1-3 and Comparative Examples 1-2, used in carbon monoxide poisoning tests. See Table 1 and... Figure 5 As shown, the effects of parameters such as process, total membrane thickness, catalyst type, additive layer thickness, additive to resin mass ratio, catalyst (M) to graphene oxide (GO) mass ratio in the additive, and additive gradient distribution on the carbon monoxide poisoning resistance of fuel cells were investigated.

[0080] A comparison of Examples 1-3 shows that Example 2 has the best performance. This is because its catalyst has the PtRu component with the best catalytic activity, and the presence of a carbon support is beneficial to the dispersion of the catalyst. In addition, it has the best parameters such as additive layer thickness, additive-to-resin mass ratio, mass ratio of catalyst (M) to graphene oxide (GO) in the additive, and additive gradient distribution.

[0081] As can be seen from the comparison of Examples 1-3 and Comparative Example 1, the proton exchange membrane and membrane electrode prepared by this method can effectively improve the resistance to carbon monoxide poisoning, with the highest improvement rate being 1.88 times compared with the proton exchange membrane without additives.

[0082] A comparison of Example 2 and Comparative Example 2 shows that the proton exchange membrane and membrane electrode prepared using the graphene functionalized anchored catalyst and gradient catalyst distribution membrane structure design strategy mentioned in this method can further improve the resistance to carbon monoxide poisoning, with an improvement rate of 1.40 times compared with the proton exchange membrane containing only catalyst.

[0083] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A highly efficient proton exchange membrane for resisting carbon monoxide poisoning, characterized in that, The proton exchange membrane is composed of an additive layer and a fluorine-containing proton exchange membrane. The additive layer is a fluorinated resin layer containing graphene oxide and an anti-carbon monoxide poisoning catalyst, wherein the graphene oxide and the anti-carbon monoxide poisoning catalyst exist in a blended manner or in a layer-by-layer stacked manner. The additive layers are located on both sides of the fluorine-containing proton exchange membrane, and the total content of graphene oxide and the anti-carbon monoxide poisoning catalyst is distributed in a gradient. The total mass ratio of graphene oxide and carbon monoxide poisoning resistant catalyst in the additive layer to the mass ratio of fluorinated resin is 0.4-10. The mass ratio of the anti-carbon monoxide poisoning catalyst to graphene oxide is 0.2-5.0%; The total content of graphene oxide and carbon monoxide poisoning resistant catalyst in the single-layer additive layer is distributed in a gradient with a thickness interval of 0.2 μm-0.5 μm. The mass ratio of the total mass of graphene oxide and carbon monoxide poisoning resistant catalyst to the mass of fluorinated resin varies from 0.002 to 0.005, and shows an increasing trend along the direction from the fluorinated proton exchange membrane to the additive layer.

2. The proton exchange membrane as described in claim 1, characterized in that, The catalyst for resisting carbon monoxide poisoning is a single metal, alloy, supported single metal or supported alloy containing catalytically active components, and the catalytically active components are selected from Pt, Ru, Rh, Pd and Mo.

3. The proton exchange membrane as described in claim 2, characterized in that, The carrier for the supported single metal and supported alloy is at least one of carbon, silicon oxide, aluminum oxide, and titanium oxide.

4. The proton exchange membrane as described in claim 1, characterized in that, The total thickness of the proton exchange membrane for resisting carbon monoxide poisoning is 8 μm-40 μm.

5. The proton exchange membrane as described in claim 1, characterized in that, The thickness of a single additive layer is 1 μm-10 μm.

6. The proton exchange membrane as described in claim 1, characterized in that, The thickness of the fluorinated proton exchange membrane is 6 μm-20 μm.

7. The method for preparing the proton exchange membrane as described in claim 1, characterized in that, When the graphene oxide and the carbon monoxide poisoning resistance catalyst in the additive layer are blended, the following steps are included: Graphene oxide powder and carbon monoxide poisoning resistance catalyst are first dispersed in an organic solvent, then mixed with a resin dispersion, coated onto a fluorine-containing proton exchange membrane, and dried to form the final product.

8. The preparation method according to claim 7, characterized in that, The dispersion process is one or more of the following: magnetic stirring, ultrasonic dispersion, ball milling, high-pressure homogenization, or microfluidization.

9. The preparation method according to claim 8, characterized in that, The ultrasonic dispersion power is 100~800 W, the ultrasonic time is 10~60 minutes, and the operation is intermittent, with 1-10 seconds of operation and 1-10 seconds of pause.

10. The preparation method according to claim 7, characterized in that, The organic solvent is one or more of water, alcohols, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

11. The preparation method according to claim 7, characterized in that, The coating method includes spraying, spin coating, scraping, or inkjet printing.

12. The preparation method according to claim 7, characterized in that, The drying and forming process is a vacuum heating drying process with a vacuum degree of -0.1 MPa and a temperature control of (40-60)℃-(70-100)℃-(110-140)℃, with each segment lasting 3-15 min.

13. The method for preparing a proton exchange membrane as described in claim 1, characterized in that, When the graphene oxide and the carbon monoxide poisoning resistance catalyst in the additive layer are stacked in a layer-by-layer manner, the following steps are included: Graphene films are transferred onto fluorine-containing proton exchange membranes using a wet process, followed by oxidation treatment using oxygen plasma. A dispersion containing a catalyst for resisting carbon monoxide poisoning and a resin dispersion are mixed and coated onto the proton exchange membrane containing graphene oxide. The mixture is then dried and shaped. This process is repeated until the last layer is coated and then dried.

14. The preparation method according to claim 13, characterized in that, The wet process is a polymethyl methacrylate-assisted wet chemical process; The oxygen plasma oxidation treatment has the following parameters: power: 20~100 W, time: 1~10 minutes, gas flow rate: 5~100 sccm, gas pressure: 10~100 mTorr. The dispersion process of the dispersion containing the catalyst for resisting carbon monoxide poisoning is one or more of the following: magnetic stirring, ultrasonic dispersion, ball milling, high-pressure homogenization, or microfluidization.

15. The preparation method according to claim 14, characterized in that, The ultrasonic dispersion power is 100~800 W, the ultrasonic time is 10~60 minutes, and the operation is intermittent, with 1-10 seconds of operation and 1-10 seconds of pause.

16. The preparation method according to claim 13, characterized in that, The solvent in the dispersion containing the catalyst against carbon monoxide poisoning is one or more of water, alcohols, N,N-dimethylformamide, N,N-dimethylacetamide, or N-methylpyrrolidone.

17. The preparation method according to claim 13, characterized in that, The drying and forming process is a vacuum heating drying process with a vacuum degree of -0.1 MPa and a temperature control of (40-60)℃-(70-100)℃-(110-140)℃, with each segment lasting 3-15 min.

18. A membrane electrode, characterized in that, The membrane electrode comprises the proton exchange membrane as described in claim 1.

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