High-entropy alloy carbon nanofiber membrane based on parallel structure, preparation method and application

Abstract

The invention discloses a high-entropy alloy carbon nanofiber membrane based on a parallel structure, a preparation method and application, and the preparation method comprises the following specific preparation steps: S1, dissolving a metal salt precursor and polyacrylonitrile in a solvent to obtain a spinning solution A; s2, polyacrylonitrile is dissolved in a solvent, and a spinning solution B is obtained; s3, performing electrostatic spinning on the spinning solution A and the spinning solution B through parallel needles to obtain a nanofiber membrane precursor with a parallel structure; and S4, the nanofiber membrane precursor is sequentially subjected to pre-oxidation and carbonization treatment, and the high-entropy alloy carbon nanofiber membrane of the parallel structure is obtained. The invention aims to solve the technical problem that an existing carbon nanofiber material for water photovoltaic power generation is difficult to consider high interfacial activity and high conductivity at the same time.

Description

Technical Field

[0001] This invention belongs to the field of carbon nanofiber membrane preparation technology, and specifically relates to high-entropy alloy carbon nanofibers based on parallel structures, their preparation methods, and applications. Background Technology

[0002] With the continued growth of global energy demand, hydroelectric power generation technology, as an emerging clean energy acquisition method, directly converts water energy in the environment into electrical energy by utilizing the interaction between water molecules and functional materials, and has attracted widespread attention. Carbon nanofiber materials, due to their excellent electrical conductivity and tunable surface properties, are used as active layer materials in hydroelectric power generation. However, existing carbon nanofiber materials for hydroelectric power generation still have the following shortcomings:

[0003] On the one hand, to enhance the interaction between water molecules and materials, it is usually necessary to hydrophilically modify carbon nanofibers or introduce functional components. Existing modification methods mostly employ post-treatment impregnation or coating processes, resulting in poor adhesion between the modified layer and the substrate, making it prone to detachment during use and affecting the long-term stability of the material.

[0004] On the other hand, while the introduction of modified components can enhance the interfacial interaction of water molecules, it often leads to a decrease in the material's conductivity, which directly determines the charge transfer efficiency during hydro-voltaic power generation. Existing materials cannot simultaneously achieve high interfacial activity and high conductivity, limiting further improvements in hydro-voltaic power generation performance. Summary of the Invention

[0005] This invention provides high-entropy alloy carbon nanofibers based on a parallel structure, their preparation method, and their applications, aiming to solve the technical problem that existing carbon nanofiber materials for hydrovoltaic power generation cannot simultaneously achieve high interfacial activity and high conductivity.

[0006] The main technical solution adopted in this invention is as follows:

[0007] A method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure, the specific preparation steps are as follows:

[0008] S1. Dissolve the metal salt precursor and polyacrylonitrile in a solvent to obtain spinning solution A;

[0009] S2. Dissolve polyacrylonitrile in a solvent to obtain spinning solution B;

[0010] S3 electrospins spinning solution A and spinning solution B through parallel needles to obtain a nanofiber membrane precursor with a parallel structure, wherein the injection speed ratio of spinning solution A to spinning solution B is 1:(1.5-7).

[0011] S4. The nanofiber membrane precursor is subjected to pre-oxidation and carbonization treatment in sequence to obtain a parallel structure high-entropy alloy carbon nanofiber membrane.

[0012] Preferably, in step S3, the injection rate of spinning solution A is 0.1-0.5 mL / h, and the injection rate of spinning solution B is 0.5-0.9 mL / h.

[0013] Preferably, the metal salt precursor includes iron salt, cobalt salt, nickel salt, magnesium salt, manganese salt and zinc salt, and the molar ratio of Fe, Co, Ni, Mg, Mn and Zn is 2:2:2:2:1:1.

[0014] Preferably, in step S1, the mass percentage concentration of the metal salt precursor in spinning solution A is 5-20 wt%; and the mass percentage concentration of the polyacrylonitrile in spinning solution A is 8-12%.

[0015] Preferably, in step S2, the mass percentage concentration of the polyacrylonitrile in the spinning solution B is 8-12%.

[0016] Preferably, in step S4, the pre-oxidation temperature is 150~250℃ and the carbonization temperature is 800-1000℃.

[0017] A high-entropy alloy carbon nanofiber membrane based on a parallel structure is prepared by the aforementioned method. The carbon nanofiber membrane is composed of a first fiber portion and a second fiber portion arranged in parallel. The first fiber portion contains high-entropy alloy nanoparticles, and the second fiber portion is pure carbon fiber.

[0018] Preferably, the cross-sectional area ratio of the first fiber portion to the second fiber portion is 1:(1.5-7).

[0019] Application of a high-entropy alloy carbon nanofiber membrane based on a parallel structure in hydrovoltaic power generation.

[0020] Beneficial effects: This invention provides high-entropy alloy carbon nanofibers based on a parallel structure, their preparation method, and their applications, which have the following advantages:

[0021] (1) The present invention adopts a parallel structure design, integrating high-entropy alloy modified carbon fiber and pure carbon fiber in the same fiber to form a functional partition: the modified side provides abundant active sites, enhances the interaction between water molecules and materials, and promotes charge generation; the unmodified side maintains the intrinsic high conductivity of carbon materials, providing a low-impedance transmission channel for charge. The synergistic effect of the two sides significantly improves the output performance of hydrovolt power generation.

[0022] (2) By adjusting the injection ratio of the spinning solution on both sides, the present invention can precisely adjust the ratio of the modified side to the unmodified side, thereby achieving independent control of the material interface activity and conductivity, and providing a flexible structural design space for the performance optimization of hydrovoltaic power generation materials.

[0023] (3) The present invention adopts parallel electrospinning combined with one-step carbonization process, the preparation process is continuous and simple to operate, no post-processing modification is required, the preparation cost is low and it is easy to scale up production. Attached Figure Description

[0024] Figure 1 A scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in Example 1;

[0025] Figure 2 This is a scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in Example 2;

[0026] Figure 3 This is a scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in Example 3;

[0027] Figure 4 This is a scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in Example 4;

[0028] Figure 5 Scanning electron microscope image of the pure high-entropy alloy carbon nanofibers prepared in Comparative Example 1;

[0029] Figure 6 The image shows a scanning electron microscope (SEM) image of the pure carbon nanofibers prepared in Comparative Example 2.

[0030] Figure 7 The images show transmission electron microscopy (TEM) and elemental analysis of the high-entropy alloy carbon nanofiber membrane prepared in Example 3. In the images, (a) is a TEM image, (b) is a carbon (C) image, (c) is an oxygen (O) image, (d) is a nickel (Ni) image, (e) is a co (Co) image, (f) is a fe (Fe) image, (g) is a zirconium (Zn) image, (h) is a magnesium (Mg) image, and (i) is a manganese (Mn) image. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application are clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0032] Example 1

[0033] Step 1: Weigh the metal precursor, polyacrylonitrile, and N,N-dimethylformamide, mix them, and heat and stir to dissolve them to obtain spinning solution A. The concentration of polyacrylonitrile is 10 wt%, and the concentration of the metal precursor is 15 wt%. The metal salt precursor consists of iron, cobalt, nickel, magnesium, manganese, and zinc salts. In a specific embodiment, the iron salt is ferric chloride hexahydrate, the cobalt salt is cobalt acetate tetrahydrate, the nickel salt is nickel acetate tetrahydrate, the magnesium salt is magnesium sulfate, the manganese salt is manganese oxide, and the zinc salt is zinc oxide. The molar ratio of Fe, Co, Ni, Mg, Mn, and Zn is 2:2:2:2:1:1. The high-entropy alloy system formed from the metal salt precursors with the above specific molar ratio can impart excellent flexibility and hydrophilicity to carbon nanofiber membranes.

[0034] Step 2: Mix polyacrylonitrile with N,N-dimethylformamide, heat and stir until completely dissolved to obtain spinning solution B. The mass percentage concentration of polyacrylonitrile is 10%.

[0035] Step 3: Spinning solution A and spinning solution B are injected into different syringes, and the two sides of the parallel needles are connected by a catheter. Then, a nanofiber membrane with a parallel structure is obtained by electrospinning. The injection rates of spinning solutions A and B are 0.5 ml / h and 0.5 ml / h, respectively. The applied DC voltage is 18 kV, the distance between the nozzle and the collecting plate is 17 cm, and the spinning time is 4.5 h.

[0036] Step 4: Peel the nanofiber membrane obtained in Step 3 from the aluminum foil and place it in an oven for pre-oxidation at 250 °C for 2 h. Place the pre-oxidized fiber membrane in a tube furnace and perform carbonization treatment under a nitrogen atmosphere: first, raise the temperature to 100 °C at a heating rate of 5 °C / min and hold for 30 min, then raise the temperature to 800 °C at a heating rate of 5 °C / min and hold for 2 h. After natural cooling, a high-entropy alloy carbon nanofiber membrane with a parallel structure is obtained.

[0037] The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this embodiment is shown below. Figure 1 As shown.

[0038] Example 2: This example is basically the same as Example 1, except that in step 3, the injection rate of spinning solution A is 0.33 mL / h, and the injection rate of spinning solution B is 0.67 mL / h. The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this example is shown below. Figure 2 As shown.

[0039] Example 3: This example is basically the same as Example 1, except that the injection rates of spinning solutions A and B in step 3 are 0.2 ml / h and 0.8 ml / h, respectively. The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this example is shown below. Figure 3 As shown.

[0040] Elemental surface scan analysis was performed on the parallel-structured high-entropy alloy carbon nanofiber membrane prepared in Example 3 using energy dispersive spectroscopy (EDS). The results are as follows: Figure 7 As shown, C and O elements are distributed on both the modified and unmodified sides of the fiber, while the six metallic elements Fe, Co, Ni, Mg, Mn, and Zn are only uniformly distributed in the modified side region of the fiber. This result indicates that the high-entropy alloy component was successfully introduced and stably exists on the modified side of the parallel fibers without cross-regional diffusion to the unmodified side, confirming that the parallel structure achieves a spatially controlled, partitioned distribution of functional components. The uniform distribution of the six elements also indicates that a homogeneous high-entropy alloy phase was formed after carbonization, providing a structural basis for its excellent photothermal conversion and hydroelectric power generation performance.

[0041] Example 4: This example is basically the same as Example 1, except that the injection rates of spinning solutions A and B in step 3 are 0.14 ml / h and 0.86 ml / h, respectively. The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this example is shown below. Figure 4 As shown.

[0042] Comparative Example 1: Compared to Example 1, the difference lies in the use of only spinning solution A for ordinary single-channel electrospinning, with a solution injection rate of 1 ml / h. The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this comparative example is shown below. Figure 5 As shown.

[0043] Comparative Example 2: Compared to Example 1, the difference lies in the use of only spinning solution B for ordinary single-channel electrospinning, with a solution injection rate of 1 ml / h. The scanning electron microscope image of the high-entropy alloy carbon nanofiber membrane prepared in this comparative example is shown below. Figure 6 As shown.

[0044] Performance testing and characterization:

[0045] (1) Surface morphology characterization

[0046] The surface morphology of carbon nanofibers in each sample was observed using scanning electron microscopy.

[0047] like Figure 5 As shown, the surface of the pure high-entropy alloy-modified carbon nanofibers in Comparative Example 1 has a large number of particulate matter distributed on it; such as Figure 6 As shown, the unmodified carbon nanofibers in Comparative Example 2 have a smooth surface. Figures 1 to 4As shown, the fibers in Examples 1-4 exhibit a distinct parallel structure, and as the injection speed of spinning solution A decreases, the particulate matter on the sample surface gradually decreases until it becomes invisible. The results indicate that the surface morphology and structure of the fibers can be effectively controlled by adjusting the solution injection speed during electrospinning.

[0048] (2) Evaporation performance test

[0049] Using a wet wipe as the water-conducting layer and polystyrene foam as the suspension layer, the wet wipe and foam were combined, and the carbon nanofiber membrane sample was placed on the wet wipe. Under simulated sunlight irradiation of one solar intensity, the mass loss rate of the system was recorded as the evaporation rate, and the surface temperature of the sample was recorded using an infrared thermal imager. The results are shown in Table 1.

[0050] Table 1. Test results of Examples 1-4 and Comparative Examples 1-2

[0051]

[0052] The test results show that as the proportion of high-entropy alloy modification decreases, the evaporation rate first increases and then decreases, while the interface temperature first decreases and then increases. Example 2 exhibits the highest evaporation rate and the lowest interface temperature. This is because: when the high-entropy alloy modification ratio is too high (e.g., Example 1, Comparative Example 1), excessive moisture is easily retained inside the fiber; although the hydrophilicity is good, the proportion of moisture participating in effective evaporation is limited. When the modification ratio is too low (e.g., Example 4, Comparative Example 2), the material's hydrophilicity is insufficient, its water conductivity decreases, and the water supply is limited. Example 2 achieves a suitable balance between hydrophilicity and water conductivity, thus obtaining the best evaporation performance.

[0053] (3) Hydroelectric power generation performance test

[0054] The hydroelectric power generation performance and evaporation performance were tested simultaneously on the same device. The output voltage and output current of the carbon nanofiber membrane were tested using a digital multimeter. Specifically, the positive terminal of the digital multimeter was connected to the sample surface, and the negative terminal was connected to the water. The test was continued until the output signal stabilized. The output voltage and output current data were recorded, and the results are shown in Table 2.

[0055] Table 2. Test results of hydroelectric power generation performance in Examples 1-4 and Comparative Examples 1-2

[0056]

[0057] As shown in Table 2, the performance of hydrovoltaic power generation exhibits a similar evolution pattern to that of evaporation rate. With the decrease in the proportion of high-entropy alloy modification, the output current and output voltage first increase and then decrease, with Example 2 showing the best performance. This is because Example 2 has the highest evaporation rate and the fastest water transport, accelerating the migration of salt ions in the water, enriching the interface layer with more salt ions, thus forming a higher induced potential difference and enhancing the induced charge movement capability. This results in a higher induced potential difference and faster induced charge movement in the interface layer, manifested as higher output voltage and output current. In Comparative Example 1, although the fully high-entropy alloy modified carbon nanofibers have good hydrophilicity, the excess water retained inside the fibers is not used for evaporation, leading to limited effective ion-induced charge movement capability, thus exhibiting lower hydrovoltaic power generation performance. In Comparative Example 2, the pure carbon nanofibers without high-entropy alloy are completely hydrophobic, with very poor water conductivity, and cannot provide a good transport channel for ions in the water, resulting in a significantly lower output current. These results further verify the superiority of the parallel structure design.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure, characterized in that, The specific preparation steps are as follows: S1. Dissolve the metal salt precursor and polyacrylonitrile in a solvent to obtain spinning solution A; S2. Dissolve polyacrylonitrile in a solvent to obtain spinning solution B; S3 electrospins spinning solution A and spinning solution B through parallel needles to obtain a nanofiber membrane precursor with a parallel structure, wherein the injection speed ratio of spinning solution A to spinning solution B is 1:(1.5-7). S4. The nanofiber membrane precursor is subjected to pre-oxidation and carbonization treatment in sequence to obtain a parallel structure high-entropy alloy carbon nanofiber membrane.

2. The method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 1, characterized in that, In step S3, the injection rate of spinning solution A is 0.1-0.5 mL / h, and the injection rate of spinning solution B is 0.5-0.9 mL / h.

3. The method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 1, characterized in that, The metal salt precursors include iron salts, cobalt salts, nickel salts, magnesium salts, manganese salts, and zinc salts, and the molar ratio of Fe, Co, Ni, Mg, Mn, and Zn is 2:2:2:2:1:

1.

4. The method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 1, characterized in that, In step S1, the mass percentage concentration of the metal salt precursor in spinning solution A is 5-20 wt%; the mass percentage concentration of the polyacrylonitrile in spinning solution A is 8-12%.

5. The method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 1, characterized in that, In step S2, the mass percentage concentration of the polyacrylonitrile in the spinning solution B is 8-12%.

6. The method for preparing a high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 1, characterized in that, In step S4, the pre-oxidation temperature is 150~250℃, and the carbonization temperature is 800-1000℃.

7. A high-entropy alloy carbon nanofiber membrane based on a parallel structure, characterized in that, The nanofiber membrane is prepared by any one of claims 1-6, wherein the nanofiber membrane is composed of a first fiber portion and a second fiber portion arranged in parallel, the first fiber portion containing high-entropy alloy nanoparticles, and the second fiber portion being pure carbon fiber.

8. The high-entropy alloy carbon nanofiber membrane based on a parallel structure according to claim 7, characterized in that, The cross-sectional area ratio of the first fiber portion to the second fiber portion is 1:(1.5-7).

9. The application of a high-entropy alloy carbon nanofiber membrane based on a parallel structure as described in claim 6 or 7 in hydrovolt power generation.

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