A method for improving hydrogen purity based on platinum nanoparticle-loaded composite nanofiber membranes

Abstract

This invention relates to a method for improving hydrogen purity using a composite nanofiber membrane based on platinum-loaded nanoparticles. The method involves cutting the platinum-loaded composite nanofiber membrane and placing it in a hydrogen purification device. Then, the hydrogen to be purified is introduced into the device, and after a reaction, oxygen impurities are removed, thus improving hydrogen purity. This invention also provides a method for preparing the platinum-loaded composite nanofiber membrane and the structure of the hydrogen purification device. This invention's method effectively removes trace amounts of oxygen impurities from hydrogen, achieving hydrogen purification with an oxygen removal rate exceeding 51.2%. Furthermore, the method provided by this invention effectively overcomes the drawback of high energy consumption in existing hydrogen purification methods, significantly reducing costs.

Description

Technical Field

[0001] This invention relates to a method for improving hydrogen purity using a composite nanofiber membrane based on loaded platinum nanoparticles, belonging to the field of gas purification. Background Technology

[0002] Hydrogen (H2) is considered an alternative to fossil fuels because it does not emit carbon to the environment and has a high energy capacity (142 kJ / g). As a renewable, pollution-free, and efficient energy medium, it is expected to become an important driving force for energy transition. Currently, the electrolysis of water to produce hydrogen using various renewable energy sources such as solar and wind power has become a popular field. However, hydrogen energy has potential risks, such as a wide range of combustible concentrations (4-75%), low ignition energy (0.02 mJ), and high diffusion coefficient (0.61 cm⁻¹). 2 The high flame propagation speed and other factors, such as the presence of oxygen in hydrogen, are risk factors hindering the large-scale utilization of hydrogen energy. In particular, the presence of oxygen in hydrogen makes it flammable and explosive over a wide concentration range, posing significant safety hazards to hydrogen production and transportation. In many industrial applications, oxygen removal from hydrogen is essential, such as in fuel cells, semiconductor manufacturing, and metal processing. Removing impurities like oxygen ensures the required hydrogen purity, improving industrial production efficiency and product quality. Oxygen can cause corrosion and oxidation reactions in certain situations, damaging equipment and pipelines. Oxygen removal reduces these adverse reactions, extends equipment lifespan, and lowers maintenance costs. Hydrogen is flammable and explosive, while oxygen is an oxidizer. The presence of oxygen in hydrogen can increase the risk of fire and explosion. Oxygen removal reduces this risk, improving workplace safety. The presence of oxygen can affect hydrogen combustion efficiency; oxygen removal improves combustion efficiency, reduces energy waste, and minimizes environmental impact. Meanwhile, as an important alternative energy source for the future, hydrogen's application areas are continuously expanding. Therefore, the purification and deoxygenation of hydrogen is of great significance for ensuring the high purity of hydrogen, the safe operation of equipment, the safety of hydrogen energy, the sustainable development of the industry, compliance with regulations and standards, and energy conservation and emission reduction.

[0003] Currently, there are several methods for hydrogen purification:

[0004] The adsorption method involves passing hydrogen gas into an adsorbent containing an adsorbent, whereby the oxygen in the hydrogen gas is adsorbed onto the adsorbent, resulting in pure hydrogen gas after oxygen removal. However, this method has the following drawbacks: (1) the adsorbent has a limited lifespan and needs to be replaced periodically; (2) the volume effect of the adsorbent under high pressure can lead to incomplete oxygen adsorption, so compression before adsorption needs to be considered.

[0005] Chemical absorption involves passing hydrogen gas into an absorber containing a chemical absorbent, causing it to react with oxygen to form easily separable compounds, resulting in pure hydrogen gas after deoxygenation. However, this method has limitations: (1) it requires the use of chemical reagents, which consumes a large amount of energy; (2) the waste liquid generated after deoxygenation needs to be treated, resulting in high subsequent costs.

[0006] Catalytic purification involves passing hydrogen gas through a catalyst, which catalytically breaks down impurities into smaller molecules, thus achieving purification. Commonly used catalysts include copper and nickel. The advantage of catalytic purification is its rapid processing speed, but its disadvantages include the need for high temperatures and pressures, resulting in higher costs.

[0007] Membrane separation is a technique that utilizes the special properties of membranes to separate impurities and hydrogen, achieving purification. Commonly used membrane separation materials include polyamide and polypropylene. The advantages of membrane separation are its simple operation and high oxygen removal rate; however, it requires high-quality membrane materials, is costly, and can lead to problems such as membrane clogging and fouling.

[0008] The high cost of equipment and materials for some hydrogen purification and deoxygenation technologies leads to high investment and operating costs, limiting their widespread adoption in large-scale industrial applications. Furthermore, these technologies consume significant amounts of energy or generate waste and pollutants, negatively impacting the environment. Additionally, hydrogen purification and deoxygenation equipment may experience performance instability or malfunctions during long-term operation, necessitating improvements in equipment stability and reliability. With the development of hydrogen energy technology, new hydrogen energy applications are placing higher demands on the purity and stability of hydrogen, which traditional hydrogen purification and deoxygenation technologies may not fully meet. Solving these problems requires continuous efforts in technological innovation and engineering practice, including developing more cost-effective and efficient hydrogen purification and deoxygenation technologies, reducing energy consumption and environmental impact, improving equipment stability and reliability, and adapting to the needs of new hydrogen energy applications. Summary of the Invention

[0009] To address the shortcomings of existing technologies, this invention provides a method for improving hydrogen purity using a composite nanofiber membrane based on platinum-loaded nanoparticles. This invention utilizes electrospinning to control the hydrolysis and oxidation of the spinning solution precursor, resulting in component segregation of the fiber membrane in air. This prepares a polymer composite nanofiber membrane with reducing properties and surface segregation of amorphous tungsten oxide. The membrane is then impregnated to obtain a platinum-loaded nanoparticle composite nanofiber membrane. The fiber membrane is highly sensitive to hydrogen, rapidly changing from yellow to deep blue in a hydrogen atmosphere and quickly fading in an oxygen atmosphere. Under the catalysis of platinum, hydrogen is rapidly dissociated into active hydrogen atoms, which combine with oxygen to form water. The fiber membrane is then placed in a self-designed hydrogen purification device to form a hydrogen purification apparatus. Using this apparatus, the hydrogen to be purified is purified by removing oxygen impurities at room temperature, thus improving hydrogen purity.

[0010] The technical solution of the present invention is as follows:

[0011] A method for improving hydrogen purity using a composite nanofiber membrane supported on platinum nanoparticles includes the following steps:

[0012] The composite nanofiber membrane loaded with platinum nanoparticles was cut and placed in a hydrogen purification device. Then, hydrogen to be purified was introduced into the hydrogen purification device. After the reaction, oxygen impurities were removed and the purity of the hydrogen was improved.

[0013] According to a preferred embodiment of the present invention, the composite nanofiber membrane loaded with platinum nanoparticles after cutting is a circle with a diameter of 4 cm.

[0014] According to a preferred embodiment of the present invention, the composite nanofiber membrane loaded with platinum nanoparticles is prepared by the following method:

[0015] (1) Preparation of spinning precursor solution

[0016] Polyacrylonitrile was added to an N,N-dimethylformamide solution and stirred until the polyacrylonitrile was completely dissolved. Then, tungsten hexachloride was added and stirred until the tungsten hexachloride was completely dissolved. The solution color turned green, and the spinning precursor solution was obtained.

[0017] (2) Preparation of composite nanofiber membranes by electrospinning

[0018] The spinning precursor solution obtained in step (1) is electrospun. After electrospinning, it is left to stand for 1-2 hours under the conditions of air humidity of 15-30% and temperature of 20-30℃ to obtain a composite nanofiber membrane.

[0019] (3) Loading of platinum nanoparticles on the surface of nanofibers

[0020] The composite nanofiber membrane obtained in step (2) was immersed in K2PtCl6 solution at 20~30℃ for 1~3h, and after rinsing and drying, a composite nanofiber membrane loaded with platinum nanoparticles was obtained.

[0021] More preferably, in step (1), the weight-average molecular weight of the polyacrylonitrile is 90,000 to 110,000, the mass-to-volume ratio of the polyacrylonitrile to the N,N-dimethylformamide solution is (0.3 to 0.5): 3, and the mass ratio of the polyacrylonitrile to the tungsten hexachloride is (0.18 to 1.75): 1.

[0022] Most preferably, the polyacrylonitrile has a weight-average molecular weight of 100,000, the mass-to-volume ratio of polyacrylonitrile to N,N-dimethylformamide solution is 0.4:3, and the mass ratio of polyacrylonitrile to tungsten hexachloride is 0.3:1.

[0023] Further preferred, in step (2), the experimental conditions for electrospinning are as follows: the spinning needle is 22G (inner diameter is 0.15 mm), the spinning distance is 15~20 cm, the spinning speed is 0.5~1 mL / h, the spinning voltage is 20~25 KV, the roller speed is 130~170 rpm, the spinning humidity is 15~25%, the temperature is 20~30 ℃, and the spinning time is 8~12 h.

[0024] More preferably, in step (3), the concentration of the K2PtCl6 solution is 2500~3000ppm, the soaking temperature is 30℃, and the soaking time is 2h.

[0025] More preferably, in step (3), the rinsing is performed by rinsing with deionized water 2 to 3 times, the drying temperature is 45 to 55°C, and the drying time is 0.5 to 1 hour.

[0026] According to a preferred embodiment of the present invention, the hydrogen purification device includes a pre-purification hydrogen storage bag, a gas flow controller, a ball valve, a gas filter, a drying tube, and a post-purification hydrogen storage bag connected in sequence by pipelines.

[0027] The gas filter includes a support plate and a sealing cover. The support plate has several membrane placement slots connected in a serpentine manner through air inlets. An air inlet is provided on the side of the support plate, and an air outlet is provided on the side opposite to the air inlet. A positioning groove is provided on the upper surface of the support plate, and the sealing cover is fixed to the support plate through the positioning groove.

[0028] More preferably, the dimensions of the support plate are 24×21×1cm. 3 The dimensions of the sealing cap are 23×20×0.2 cm. 3 .

[0029] More preferably, the membrane placement groove is a circular groove with a diameter of 4cm and a depth of 6mm, and there are 20 of them, evenly distributed in the support plate; the air inlet is connected to the first membrane placement groove, and the air outlet is connected to the twentieth membrane placement groove; the width of the air guide hole is 12mm.

[0030] More preferably, the gas filter is made of photocurable resin and is obtained by printing with a 3D photocurable printer; the sealing cover is made of transparent acrylic sheet, and the support plate and the sealing cover are sealed with hot melt adhesive.

[0031] Preferably, the photocurable resin is a rigid resin with a viscosity of 200~400 mPa·s, a liquid density of 1.05~1.25 g / cm3, an exposure time of 3 s, a molding hardness of 80~88 D, and a volume shrinkage rate of 0.2~0.7% after curing. The maximum flexural strength is 30.115±10%, and the maximum tensile strength is 33.781±10%. The hot melt adhesive used is EVA resin.

[0032] The technical features and superior effects of this invention are as follows:

[0033] 1. This invention first prepares an amorphous tungsten oxide / polymer composite nanofiber membrane with reducing properties and surface segregation. Then, through subsequent soaking, platinum nanoparticles are loaded onto the surface of the composite nanofiber membrane, resulting in a platinum-loaded composite nanofiber membrane with advantages of high porosity and good air permeability. Furthermore, this platinum-loaded composite nanofiber membrane, through surface segregation, exhibits a higher content of the functional component tungsten oxide on the fiber surface. It rapidly turns blue in a hydrogen atmosphere and quickly fades from blue in oxidizing atmospheres such as oxygen, demonstrating its ability to react with oxygen rapidly. Simultaneously, it requires a relatively low amount of precious metal, allowing for large-scale preparation. The fiber membrane also exhibits good stability and can be reused multiple times.

[0034] 2. The hydrogen purification device provided by this invention includes a pre-purification hydrogen storage bag, a gas flow controller, a ball valve, a gas filter, a drying tube, and a post-purification hydrogen storage bag connected sequentially by pipelines. A composite nanofiber membrane loaded with platinum nanoparticles is placed sequentially inside the gas filter, allowing gas to pass through layers of the composite nanofiber membrane loaded with platinum nanoparticles, achieving oxygen removal at room temperature. Furthermore, this hydrogen purification device can connect multiple gas filters in series to further improve the hydrogen purification effect. Moreover, the hydrogen purification device has a stable oxygen removal effect, can be reused, and reduces the cost of hydrogen purification.

[0035] 3. This invention combines a composite nanofiber membrane loaded with platinum nanoparticles with a self-designed hydrogen purification device, providing a method to improve hydrogen purity. This method utilizes the characteristic that hydrogen can be rapidly dissociated into active hydrogen atoms under the catalytic action of the composite nanofiber membrane loaded with platinum nanoparticles. These hydrogen atoms combine with oxygen to form water. The oxygen is consumed through this reaction, and the water generated in the reaction is then removed through a subsequent drying tube. This effectively removes trace amounts of oxygen impurities from hydrogen, improving its purity and achieving a hydrogen purification effect with an oxygen removal rate exceeding 51.2%. Furthermore, the method provided by this invention effectively solves the drawback of high energy consumption in existing hydrogen deoxygenation and purification methods, significantly reducing costs. Attached Figure Description

[0036] Figure 1 This is an optical photograph of the spinning precursor solution in Example 1;

[0037] Figure 2 This is an optical photograph of the fiber membrane obtained after electrospinning in Example 1;

[0038] Figure 3 This is an optical photograph of the fiber membrane obtained after electrospinning in Example 1 after it has segregated in the air;

[0039] Figure 4 This is a SEM image of the composite nanofiber membrane in Example 1;

[0040] Figure 5 This is a TEM image of the composite nanofiber membrane loaded with platinum nanoparticles in Example 1;

[0041] Figure 6 These are optical photographs showing the color changes of the composite nanofiber membrane loaded with platinum nanoparticles prepared in Example 1 before and after hydrogen gas is introduced.

[0042] Figure 7 This is a schematic diagram of the hydrogen purification device in Example 2;

[0043] Figure 8 This is a schematic diagram of the gas filter structure in Example 2;

[0044] Figure 9 Example 4 is a schematic diagram showing the diameter of the disc obtained after cutting the composite nanofiber membrane loaded with platinum nanoparticles.

[0045] Figure 10 This is a physical image of the gas filter formed by encapsulating a composite nanofiber membrane loaded with platinum nanoparticles into the gas filter of Example 4.

[0046] Figure 11 This is a data graph showing the deoxygenation process during hydrogen purification in Example 4;

[0047] Figure 12 This is a data graph showing the deoxygenation process during hydrogen purification in Example 5;

[0048] Figure 13 This is a data graph showing the deoxygenation process during hydrogen purification in Example 6;

[0049] In the diagram, 1. Hydrogen storage bag before purification, 2. Gas flow controller, 3. Ball valve, 4. Gas filter, 5. Drying tube, 6. Hydrogen storage bag after purification, 7. Gas inlet, 8. Membrane placement tank, 9. Support plate, 10. Positioning tank, 11. Gas inlet, 12. Gas outlet, 13. Sealing cap. Detailed Implementation

[0050] To better understand this invention, specific embodiments are described below. All raw materials and equipment used in the embodiments are conventional. Unless otherwise specified, all materials and reagents used are commercially available.

[0051] The gas flow controller mentioned is model HORIBA Z719, which can control the flow rate of gas and is available from Beijing Ruining Technology Co., Ltd.

[0052] Example 1

[0053] A composite nanofiber membrane loaded with platinum nanoparticles is prepared according to the following method:

[0054] (1) Preparation of spinning precursor solution

[0055] 2.4 g of polyacrylonitrile (PAN, weight average molecular weight 100,000) was added to 18 mL of N,N-dimethylformamide (DMF) solution. After stirring until the polyacrylonitrile was completely dissolved, 3 g of tungsten hexachloride (WCl6) was added, and stirring continued. The solution gradually changed from an orange transparent state to a green transparent state. Figure 1 This process yields a spinning precursor solution, which is then used for spinning.

[0056] (2) Preparation of composite nanofiber membranes by electrospinning

[0057] Electrospinning was performed using a TL-0123 electrospinning machine from Tongli Micro-Nano Technology Co., Ltd. Specifically, the spinning precursor solution obtained in step (1) was selected, and 9 mL of solution was drawn from each of two 10 mL syringes. These were connected using matching Luer connectors and PTFE tubing. A 22G spinning needle (0.15 mm inner diameter) was selected for electrospinning. The resulting fiber membrane exhibited a green surface and a blue interior (appearance as shown in the image). Figure 2 (As shown); after electrospinning, if the fiber membrane is left to stand for 2 hours at an air humidity of 23% and a temperature of 25℃, the surface of the fiber membrane will gradually change from green to blue (appearance after segregation as shown). Figure 3 As shown in the figure, a composite nanofiber membrane is obtained; the composite nanofiber membrane is an amorphous tungsten oxide / polymer composite nanofiber membrane with reducing properties and surface segregation.

[0058] The parameters for electrospinning are as follows: spinning distance is 18 cm, spinning speed is 0.7 mL / h, spinning voltage is 23 KV, roller speed is 150 rpm, spinning humidity is 15%, temperature is 25℃, and spinning time is 10 h.

[0059] The SEM image of the composite nanofiber membrane obtained in this step is as follows: Figure 4 As shown, the uneven surface of the fiber is due to the segregation of amorphous tungsten oxide, and the average diameter of the fiber is 840 nm.

[0060] (3) Loading of platinum nanoparticles on the surface of nanofibers

[0061] The composite nanofiber membrane obtained in step (2) was cut into 5×5cm squares and placed in a custom-made square box containing 10 mL of a 3000 ppm K2PtCl6 solution. The composite nanofiber membrane initially faded from blue to yellow, and the soaking time was 2 hours at 25°C. After soaking, the composite nanofiber membrane was removed, rinsed twice with deionized water, and dried in an oven at 50°C for 30 minutes. The TEM image of the obtained platinum-loaded nanofiber membrane is shown below. Figure 5 As shown in the figure, the black spots are the loaded platinum nanoparticles. Simultaneously, passing hydrogen gas reveals a yellow film of loaded platinum nanoparticle fibers. Figure 6 The left side will quickly turn blue. Figure 6 right).

[0062] Example 2

[0063] like Figures 7-8 As shown, a hydrogen purification device includes a pre-purification hydrogen storage bag 1, a gas flow controller 2, a ball valve 3, a gas filter 4, a drying tube 5, and a post-purification hydrogen storage bag 6 connected in sequence; the gas flow controller 4 is a HORIBA Z719; the hydrogen to be purified is stored in the pre-purification hydrogen storage bag 1, the purified hydrogen is stored in the post-purification hydrogen storage bag 6, and the drying tube 5 dries the water generated during the purification process;

[0064] The gas filter 4 includes a support plate 9 and a sealing cover 13. The support plate 9 has 20 membrane placement slots 8, which are connected in a serpentine manner within the support plate 9 via air inlets 11. An air inlet 7 is provided on the side of the support plate 9, and an air outlet 12 is provided on the side of the support plate 9 opposite to the air inlet 7. A positioning groove 10 is provided on the upper surface of the support plate 9, and the sealing cover 13 is fixed to the support plate 9 via the positioning groove 10.

[0065] The dimensions of the support plate 9 are 24×21×1cm. 3 The dimensions of the sealing cap 13 are 23 × 20 × 0.2 cm. 3 The membrane placement groove 8 is a circular groove with a diameter of 4cm and a depth of 6mm, and is evenly distributed within the support plate 9; the air inlet 7 is connected to the first membrane placement groove 8, and the air outlet 12 is connected to the twentieth membrane placement groove 8; the air guide port 11 has a width of 12mm.

[0066] The gas filter 4 is made of photocurable resin and printed using a Saturn 3 Ultra 3D photocurable printer from Shenzhen SmartPai Technology Co., Ltd. The sealing cover 13 is made of transparent acrylic sheet, and the support plate 9 and the sealing cover 13 are sealed with hot melt adhesive. The photocurable resin is a rigid resin with a viscosity of 300 mPa·s and a liquid density of 1.25 g / cm³. 3 The exposure time is 3 seconds, the molding hardness is 85 D, and the volume shrinkage rate after curing is 0.5%. The maximum flexural strength is 30.115±10%, and the maximum tensile strength is 33.781±10%. The hot melt adhesive used is EVA resin.

[0067] Example 3

[0068] A hydrogen purification device, structured as described in Example 2, except that two gas filters 4 are connected in series, with the inlet of one gas filter 4 connected to the outlet of the other gas filter 4.

[0069] Example 4

[0070] A method for improving hydrogen purity using a composite nanofiber membrane supported on platinum nanoparticles includes the following steps:

[0071] The composite nanofiber membrane loaded with platinum nanoparticles prepared in Example 1 was cut into circles with a diameter of 4 cm (e.g., Figure 9 As shown in the figure, the membranes are sequentially placed in the membrane placement slot of the gas filter 4 of the hydrogen purification device described in Example 2. The sealing cap 13 is placed on the positioning slot 10 of the gas filter 4 support plate 9. The gas filter 4 is sealed with hot melt adhesive to prevent gas leakage. The actual picture of the gas filter 4 containing the composite nanofiber membrane loaded with platinum nanoparticles is shown in the figure. Figure 10 As shown, hydrogen to be purified is then introduced into the hydrogen purification device. After the reaction, oxygen impurities are removed, and the purity of the hydrogen is improved.

[0072] The oxygen content in the hydrogen gas to be purified introduced in this embodiment, as well as the oxygen content in the treated hydrogen gas obtained over a continuous period of time, were measured and data were recorded every minute. The results are as follows: Figure 11 As shown.

[0073] Depend on Figure 11 It can be seen that the oxygen content in the hydrogen to be purified decreased from the initial value of 0.172% to 0.084%, with an oxygen removal rate of 51.2%. This indicates that the present invention combines a composite nanofiber membrane loaded with platinum nanoparticles with a self-made gas filter, providing a method to improve the purity of hydrogen, which can remove oxygen impurities and is effective in removing trace amounts of oxygen impurities from hydrogen.

[0074] Example 5

[0075] A method for improving hydrogen purity using a composite nanofiber membrane supported on platinum nanoparticles includes the following steps:

[0076] The composite nanofiber membrane loaded with platinum nanoparticles prepared in Example 1 was cut into circles with a diameter of 4 cm and placed sequentially into the membrane placement groove of the gas filter 4 of the hydrogen purification device described in Example 2. The sealing cap 13 was placed on the positioning groove 10 of the support plate 9 of the gas filter 4. The gas filter 4 was sealed with hot melt adhesive to prevent gas leakage. Then, the hydrogen to be purified was introduced into the hydrogen purification device. After the reaction, oxygen impurities were removed and the purity of the hydrogen was improved.

[0077] The oxygen content in the hydrogen gas to be purified introduced in this embodiment, as well as the oxygen content in the treated hydrogen gas obtained over a continuous period of time, were measured and data were recorded every minute. The results are as follows: Figure 12 As shown.

[0078] Depend on Figure 12 It can be seen that the oxygen content in the hydrogen to be purified decreased from the initial value of 1.745% to 1.605%, and the oxygen removal rate was 8%.

[0079] Example 6

[0080] A method for improving hydrogen purity using a composite nanofiber membrane supported on platinum nanoparticles includes the following steps:

[0081] The composite nanofiber membrane loaded with platinum nanoparticles prepared in Example 1 was cut into circles with a diameter of 4 cm and placed sequentially into the membrane placement groove of the gas filter 4 of the hydrogen purification device described in Example 2. The sealing cap 13 was placed on the positioning groove 10 of the support plate 9 of the gas filter 4. The gas filter 4 was sealed with hot melt adhesive to prevent gas leakage. Then, the hydrogen to be purified was introduced into the hydrogen purification device. After the reaction, oxygen impurities were removed and the purity of the hydrogen was improved.

[0082] The oxygen content in the hydrogen gas to be purified introduced in this embodiment, as well as the oxygen content in the treated hydrogen gas obtained over a continuous period of time, were measured and data were recorded every minute. The results are as follows: Figure 13 As shown.

[0083] Depend on Figure 13 It can be seen that the oxygen content in the hydrogen to be purified decreased from the initial value of 1.745% to 1.426%, and the oxygen removal rate was 18.04%. This indicates that the method provided by the present invention can further improve the purification effect of impurity oxygen in hydrogen by increasing the number of gas filters, and the multiple filters have a synergistic effect, producing a result greater than the sum of its parts.

Claims

1. A method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles, characterized in that, The steps include the following: The composite nanofiber membrane loaded with platinum nanoparticles was cut and placed in a hydrogen purification device. Then, the hydrogen to be purified was introduced into the hydrogen purification device. After the reaction, oxygen impurities were removed and the purity of the hydrogen was improved. The composite nanofiber membrane loaded with platinum nanoparticles was prepared according to the following method: (1) Preparation of spinning precursor solution Polyacrylonitrile was added to an N,N-dimethylformamide solution and stirred until the polyacrylonitrile was completely dissolved. Then, tungsten hexachloride was added and stirred until the tungsten hexachloride was completely dissolved. The solution color turned green, and the spinning precursor solution was obtained. (2) Preparation of composite nanofiber membranes by electrospinning The spinning precursor solution obtained in step (1) is electrospun. After electrospinning, it is left to stand for 1-2 hours under the conditions of air humidity of 15-30% and temperature of 20-30℃ to obtain a composite nanofiber membrane. (3) Loading of platinum nanoparticles on the surface of nanofibers The composite nanofiber membrane obtained in step (2) was immersed in K2PtCl6 solution at 20~30℃ for 1~3h, and after rinsing and drying, a composite nanofiber membrane loaded with platinum nanoparticles was obtained.

2. The method for improving hydrogen purity based on composite nanofiber membranes loaded with platinum nanoparticles as described in claim 1, characterized in that, The cut composite nanofiber membrane loaded with platinum nanoparticles is a circle with a diameter of 4 cm.

3. The method for improving hydrogen purity based on composite nanofiber membranes loaded with platinum nanoparticles as described in claim 1, characterized in that, In step (1), the weight-average molecular weight of the polyacrylonitrile is 90,000 to 110,000, the mass-to-volume ratio of polyacrylonitrile to N,N-dimethylformamide solution is (0.3 to 0.5) g: 3 mL, and the mass ratio of polyacrylonitrile to tungsten hexachloride is (0.18 to 1.75):

1.

4. The method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles as described in claim 1, characterized in that, In step (2), the experimental conditions for electrospinning are as follows: the spinning needle is 22G, the spinning distance is 15~20cm, the spinning speed is 0.5~1mL / h, the spinning voltage is 20~25KV, the roller speed is 130~170rpm, the spinning humidity is 15~25%, the temperature is 20~30℃, and the spinning time is 8~12h.

5. The method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles as described in claim 1, characterized in that, In step (3), the concentration of the K2PtCl6 solution is 2500~3000ppm, the soaking temperature is 30℃, and the soaking time is 2h; the rinsing is done by rinsing with deionized water 2~3 times, the drying temperature is 45~55℃, and the drying time is 0.5~1h.

6. The method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles as described in claim 1, characterized in that, The hydrogen purification device includes a pre-purification hydrogen storage bag, a gas flow controller, a ball valve, a gas filter, a drying tube, and a post-purification hydrogen storage bag, which are connected in sequence by pipelines. The gas filter includes a support plate and a sealing cover. The support plate has several membrane placement slots connected in a serpentine manner through air inlets. An air inlet is provided on the side of the support plate, and an air outlet is provided on the side opposite to the air inlet. A positioning groove is provided on the upper surface of the support plate, and the sealing cover is fixed to the support plate through the positioning groove.

7. The method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles as described in claim 6, characterized in that, The dimensions of the support plate are 24×21×1cm. 3 The dimensions of the sealing cap are 23×20×0.2 cm. 3 .

8. The method for improving hydrogen purity based on composite nanofiber membranes loaded with platinum nanoparticles as described in claim 6, characterized in that, The membrane placement grooves are circular grooves with a diameter of 4cm and a depth of 6mm, and there are 20 of them, evenly distributed in the support plate; the air inlet is connected to the first membrane placement groove, and the air outlet is connected to the twentieth membrane placement groove; the width of the air guide is 12mm.

9. The method for improving hydrogen purity based on a composite nanofiber membrane loaded with platinum nanoparticles as described in claim 6, characterized in that, The gas filter is made of photocurable resin and is printed using a 3D photocurable printer; the sealing cover is made of transparent acrylic sheet, and the support plate and the sealing cover are sealed with hot melt adhesive.

Images