A Co-doped Ni3V2O8 electrocatalytic material, its preparation method and application

Abstract

This invention relates to a Co-doped Ni3V2O8 electrocatalytic material, its preparation method, and its applications. The electrocatalytic material has a microstructure consisting of nanofibers composed of a mixture of Co-doped Ni3V2O8 particles. The nanofibers exhibit a uniform and continuous morphology, with diameters ranging from 50 to 120 nm and lengths from 1 to 5 μm, possessing a large aspect ratio of 10 to 100. This invention utilizes Co doping and directly prepares the Co-doped Ni3V2O8 electrocatalytic material via electrospinning combined with calcination. This significantly improves the oxygen reduction performance of Ni3V2O8 materials, offering low cost, simple operation, and promising application prospects.

Description

Technical Field

[0001] This invention relates to a Co-doped Ni3V2O8 electrocatalytic material, its preparation method and application, belonging to the field of electrocatalytic material technology. Background Technology

[0002] With the advent of the global energy crisis and environmental degradation, the development of scientific, efficient, green, and sustainable energy has become a key focus of research in countries worldwide. The continued consumption of fossil fuels has spurred the development of energy storage and conversion devices, among which fuel cells are devices that directly convert the chemical energy of fuel into electrical energy.

[0003] The oxygen reduction reaction (ORR) is a crucial reaction for energy conversion in metal-air batteries and fuel cells. Oxygen undergoes electron transfer, forming peroxides through a two-electron process or water through a four-electron process. However, the ORR pathway is complex, involving multiple elementary reactions and various intermediate products. It also has a high activation energy and a slow intrinsic kinetic rate, making ORR efficiency a key factor limiting the performance of these two types of devices. Traditional platinum, platinum alloys, and other noble metal catalysts exhibit good ORR catalytic activity, but their high cost, scarcity, and susceptibility to poisoning in the working environment limit their large-scale application. From a cost and sustainable development perspective, developing high-performance, low-cost ORR electrocatalysts is one of the important directions for promoting the development of fuel cells and metal-air batteries.

[0004] Co, Ni, and V are all transition metal elements, widely available, abundant, and low in cost. Ni3V2O8 is a typical A3V2O8 type binary metal oxide, which has been widely used in photocatalysis, supercapacitors, and other fields. For example, Chinese patent document CN113385181A discloses a flexible bismuth molybdate / nickel vanadate photocatalytic material, its preparation method, and its application. The microstructure of the flexible bismuth molybdate / nickel vanadate photocatalytic material consists of irregular bismuth molybdate nanosheets loaded on the surface of nickel vanadate nanofibers. This method promotes the separation and transfer of photogenerated carriers and improves photocatalytic performance by constructing an n-type heterojunction formed by bismuth molybdate and nickel vanadate. However, this flexible photocatalytic material first requires the construction of bismuth molybdate / nickel vanadate nanofibers, and then the nanofibers need to be adhered to conductive tape, requiring at least two steps. The method is cumbersome, costly, and offers limited improvement in photocatalytic performance.

[0005] Chinese patent document CN109599271A discloses an electrode material Ni3V2O8 and its synthesis method. The method uses a microwave-assisted method to synthesize Ni3V2O8 microspheres. However, this method consumes a lot of energy and the prepared Ni3V2O8 microspheres are not uniformly aggregated.

[0006] Therefore, there is an urgent need to develop a new type of electrocatalytic material that is low in cost, simple to operate, highly efficient and pollution-free, and can improve the performance of electrocatalytic oxygen reduction. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a Co-doped Ni3V2O8 electrocatalytic material, its preparation method, and its applications. This invention directly utilizes a sol-electrospinning combined with calcination technology to prepare fibrous Co-doped Ni3V2O8 electrocatalytic material. Compared to particulate materials, the one-dimensional nanostructure of this material facilitates the exposure of more active sites, significantly improving the oxygen reduction performance of Ni3V2O8. It is low-cost, simple to operate, and has promising application prospects.

[0008] Terminology Explanation:

[0009] Room temperature: as is known to those skilled in the art, refers to 25±5℃.

[0010] Spinning receiving distance: The distance from the electrospinning needle to the receiving device.

[0011] The technical solution of the present invention is as follows:

[0012] A Co-doped Ni3V2O8 electrocatalytic material, wherein the microstructure of the electrocatalytic material is composed of nanofibers made up of mixed Co-doped Ni3V2O8 particles, with a uniform and continuous morphology. The nanofibers have a diameter of 50-120 nm, a length of 1-5 μm, and a large aspect ratio of 10-100.

[0013] According to the present invention, the preparation method of the above-mentioned Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0014] (1) Dissolve nickel source, cobalt source, vanadium source and citric acid in deionized water, then add acid solution dropwise and stir to obtain precursor solution;

[0015] (2) Dissolve polyvinylpyrrolidone (PVP) in ethanol, add the precursor solution obtained in step (1) to it to obtain precursor sol; electrospin the precursor sol at room temperature to obtain precursor fiber; dry and calcine the obtained precursor fiber to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0016] According to a preferred embodiment of the present invention, the nickel source in step (1) is nickel acetate tetrahydrate or nickel nitrate hexahydrate, the cobalt source is cobalt nitrate hexahydrate, and the vanadium source is ammonium metavanadate.

[0017] According to a preferred embodiment of the present invention, in step (1), the molar amount of the vanadium source to the mass ratio of citric acid is (0.3-0.6) mmol:(0.3-0.6) g.

[0018] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the vanadium source to the volume ratio of deionized water is (0.3-0.6) mmol: (2-5) mL.

[0019] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the vanadium source to the nickel source is (0.3-0.6):(0.3-0.6).

[0020] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the nickel source to the cobalt source is (0.6-0.3):(0.01-0.5).

[0021] According to a preferred embodiment of the present invention, in step (1), the acid solution is a hydrochloric acid solution, a nitric acid solution, or an acetic acid solution, wherein the mass concentration of the hydrochloric acid solution is 37 wt%, the mass concentration of the nitric acid solution is 66 wt%, and the mass concentration of the acetic acid solution is 99 wt%.

[0022] According to a preferred embodiment of the present invention, in step (1), the molar ratio of the vanadium source to the volume of the acid solution is (0.3-0.6) mmol: (0.2-2) mL.

[0023] According to a preferred embodiment of the present invention, the stirring time in step (1) is 60-120 min.

[0024] According to a preferred embodiment of the present invention, the weight-average molecular weight of the polyvinylpyrrolidone (PVP) in step (2) is 1,000,000 to 1,500,000; more preferably, the weight-average molecular weight of the polyvinylpyrrolidone is 1,300,000.

[0025] According to a preferred embodiment of the present invention, the mass-to-volume ratio of polyvinylpyrrolidone (PVP) to ethanol in step (2) is (0.6-1.6) g: (10-15) mL, and more preferably (0.8-1.0) g: (10-12) mL.

[0026] According to a preferred embodiment of the present invention, the volume ratio of the precursor solution to ethanol in step (2) is (2-5):(10-12).

[0027] According to a preferred embodiment of the present invention, in step (2), the voltage of electrospinning is 15-28kV, the relative humidity is 10-35%, the receiving distance is 10-30cm, and the advancing speed is 0.8-1.2mL / h;

[0028] More preferably, the electrospinning voltage is 18-25kV.

[0029] According to a preferred embodiment of the present invention, the drying temperature in step (2) is 40-60°C and the drying time is 12-18h.

[0030] According to a preferred embodiment of the present invention, the calcination temperature in step (2) is 500°C, the heating rate is 1-5°C / min, and the calcination time is 120min.

[0031] This invention uses sol-electrospinning technology to prepare Co-doped Ni3V2O8 fiber membranes, and then calcines the fiber membranes to obtain Co-doped Ni3V2O8 nanofibers with a diameter of 50-120 nm.

[0032] According to the present invention, the above-mentioned Co-doped Ni3V2O8 electrocatalytic material is applied to the oxygen reduction reaction (ORR).

[0033] All chemicals used in this invention are of analytical grade and have not undergone further processing.

[0034] The technical features and beneficial effects of this invention are as follows:

[0035] 1. This invention prepares Ni3V2O8 nanofibers with varying Co content by doping with a specific element, Co, and controlling the amount of Co source, using a sol-electrospinning technique combined with a calcination process. The Co-doped Ni3V2O8 electrocatalytic material prepared by this invention exhibits excellent oxygen reduction (ORR) performance. The one-dimensional nanostructure material facilitates the exposure of more active sites, significantly enhancing electrocatalytic performance. Too low a Co content results in minimal improvement in electrocatalytic performance; while too high a Co content leads to the formation of other substances. Therefore, an appropriate amount of Co maximizes electrocatalytic performance. The key to this invention is controlling the Co doping amount.

[0036] 2. The preparation method of the present invention has low raw material cost, simple process equipment, controllable preparation process, no wastewater or waste gas emission, and has the potential for large-scale production.

[0037] 3. The Co-doped Ni3V2O8 nanofibers prepared by this invention have uniform morphology and good continuity. The electrocatalytic material is green and pollution-free, and will not generate secondary pollution during application, which is conducive to promoting sustainable environmental development. Attached Figure Description

[0038] Figure 1 X-ray diffraction patterns of different materials were prepared for Examples 1-5, Comparative Example 1 and Comparative Example 2.

[0039] Figure 2 Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 1;

[0040] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0041] Figure 3Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 2;

[0042] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0043] Figure 4 Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 3;

[0044] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0045] Figure 5 Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 4;

[0046] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0047] Figure 6 Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 5;

[0048] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0049] Figure 7 Transmission electron microscopy image of the Ni3V2O8 electrocatalytic material prepared in Comparative Example 1;

[0050] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0051] Figure 8 Transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in Comparative Example 2;

[0052] In the image, a is a low-magnification transmission electron microscope (TEM) image; b is a high-magnification transmission electron microscope (TEM) image.

[0053] Figure 9 LSV curves of ORR for different electrocatalytic materials prepared in Examples 1-5 in O2-saturated 0.1M KOH solution at a scan rate of 10mV / s.

[0054] Figure 10 LSV curves of ORR for different electrocatalytic materials prepared for Comparative Example 1 and Comparative Example 2 in O2-saturated 0.1M KOH solution at a scan rate of 10mV / s. Detailed Implementation

[0055] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but these are not intended to limit the scope of protection of the present invention.

[0056] All raw materials and equipment used in the examples are conventional and can be purchased commercially.

[0057] Example 1

[0058] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0059] (1) Dissolve 0.0946 g nickel acetate tetrahydrate, 0.0640 g cobalt nitrate hexahydrate, 0.0468 g ammonium metavanadate and 0.30 g citric acid in 2 mL of deionized water, and then add 0.5 mL of hydrochloric acid with a mass concentration of 37 wt% dropwise. Stir for 120 min to obtain the precursor solution.

[0060] (2) Weigh 0.8g of polyvinylpyrrolidone (PVP) and dissolve it in 10mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 20kV pressure, 30% relative humidity and room temperature, with a spinning receiving distance of 20cm and a pushing speed of 1mL / h to obtain precursor fibers.

[0061] (3) The precursor fiber obtained in step (2) is dried at 40°C for 12 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 1°C / min. It is then kept at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0062] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this embodiment is as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0063] The transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in this embodiment is as follows: Figure 2 As shown. From Figure 2 It can be seen that the prepared nanofibers with a diameter of 50-100 nm have a large aspect ratio and a uniform and continuous morphology.

[0064] Example 2

[0065] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0066] (1) Dissolve 0.1047g nickel nitrate hexahydrate, 0.0698g cobalt nitrate hexahydrate, 0.0468g ammonium metavanadate and 0.50g citric acid in 4mL of deionized water, then add 0.6mL of nitric acid with a mass concentration of 66wt% dropwise and stir for 90min to obtain the precursor solution;

[0067] (2) Weigh 0.9g of polyvinylpyrrolidone (PVP) and dissolve it in 11mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 22kV pressure, 20% relative humidity and room temperature, with a spinning receiving distance of 18cm and a pushing speed of 0.8mL / h to obtain precursor fibers.

[0068] (3) The precursor fiber obtained in step (2) was dried at 40°C for 14 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 2°C / min. The temperature was then maintained at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0069] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this embodiment is as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0070] The transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in this embodiment is as follows: Figure 3 As shown. From Figure 3 It can be seen that the prepared sample is composed of nanofibers with a diameter of 50-120 nm and a large aspect ratio.

[0071] Example 3

[0072] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0073] (1) Dissolve 0.0846 g nickel acetate tetrahydrate, 0.0756 g cobalt nitrate hexahydrate, 0.0468 g ammonium metavanadate and 0.40 g citric acid in 3 mL of deionized water, then add 0.8 mL of acetic acid with a mass concentration of 99 wt% dropwise, stir for 120 min to obtain the precursor solution;

[0074] (2) Weigh 1g of polyvinylpyrrolidone (PVP) and dissolve it in 12mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 23kV pressure, 25% relative humidity and room temperature, with a spinning receiving distance of 15cm and a pushing speed of 0.8mL / h to obtain precursor fibers.

[0075] (3) The precursor fiber obtained in step (2) was dried at 60°C for 16 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 3°C / min. The temperature was then maintained at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0076] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this embodiment is as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0077] The transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in this embodiment is as follows: Figure 4 As shown. From Figure 4 It can be seen that the prepared sample is composed of nanofibers with a diameter of 50-120 nm and a large aspect ratio.

[0078] Example 4

[0079] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0080] (1) Dissolve 0.0930g nickel nitrate hexahydrate, 0.0814g cobalt nitrate hexahydrate, 0.0468g ammonium metavanadate and 0.60g citric acid in 5mL of deionized water, and then add 0.6mL of hydrochloric acid with a mass concentration of 37wt% dropwise. Stir for 60min to obtain the precursor solution.

[0081] (2) Weigh 0.8g of polyvinylpyrrolidone (PVP) and dissolve it in 12mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 18kV pressure, 15% relative humidity and room temperature, with a spinning receiving distance of 22cm and a pushing speed of 1mL / h to obtain precursor fibers.

[0082] (3) The precursor fiber obtained in step (2) was dried at 40°C for 18 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 3°C / min. It was then held at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0083] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this embodiment is as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0084] The transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in this embodiment is as follows: Figure 5 As shown. From Figure 4 It can be seen that the prepared sample is composed of nanofibers with small particles, which are more obvious and have a diameter of 50-120 nm.

[0085] Example 5

[0086] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0087] (1) Dissolve 0.0746 g nickel acetate tetrahydrate, 0.0873 g cobalt nitrate hexahydrate, 0.0468 g ammonium metavanadate and 0.40 g citric acid in 3 mL of deionized water, then add 0.5 mL of hydrochloric acid with a mass concentration of 37 wt%, stir for 90 min to obtain the precursor solution;

[0088] (2) Weigh 0.9g of polyvinylpyrrolidone (PVP) and dissolve it in 11mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 25kV pressure, 15% relative humidity and room temperature, with a spinning receiving distance of 25cm and a pushing speed of 1mL / h to obtain precursor fibers.

[0089] (3) The precursor fiber obtained in step (2) was dried at 60°C for 12 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 1°C / min. It was then held at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0090] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this embodiment is as follows: Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0091] The transmission electron microscope (TEM) image of the Co-doped Ni3V2O8 electrocatalytic material prepared in this embodiment is as follows: Figure 6 As shown. From Figure 6 It can be seen that the prepared sample is composed of nanofibers with a diameter of 50-120 nm.

[0092] Comparative Example 1

[0093] A method for preparing Ni3V2O8 electrocatalytic material includes the following steps:

[0094] (1) Dissolve 0.1494 g nickel acetate tetrahydrate, 0.0468 g ammonium metavanadate and 0.40 g citric acid in 3 mL deionized water, then add 0.5 mL hydrochloric acid with a mass concentration of 37 wt% dropwise, stir for 120 min to obtain the precursor solution;

[0095] (2) Weigh 0.8g of polyvinylpyrrolidone (PVP) and dissolve it in 10mL of anhydrous ethanol and stir until homogeneous; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 20kV pressure, 10% relative humidity and room temperature, with a spinning receiving distance of 20cm and a pushing speed of 0.8mL / h to obtain precursor fibers.

[0096] (3) The precursor fiber obtained in step (2) was dried at 40°C for 12 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 1°C / min. It was then held at 500°C for 120 minutes to obtain Ni3V2O8 electrocatalytic material.

[0097] The X-ray diffraction (XRD) pattern of the Ni3V2O8 electrocatalyst material prepared in this comparative example is shown below. Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0098] The Ni3V2O8 electrocatalytic material prepared in this comparative example is shown in the transmission electron microscope (TEM) image. Figure 7 As shown. From Figure 7 It can be seen that the prepared sample is composed of nanofibers with a diameter of 50-120 nm.

[0099] Comparative Example 2

[0100] A method for preparing a Co-doped Ni3V2O8 electrocatalytic material includes the following steps:

[0101] (1) Dissolve 0.1169 g nickel nitrate hexahydrate, 0.0480 g cobalt nitrate hexahydrate, 0.0468 g ammonium metavanadate and 0.50 g citric acid in 4 mL of deionized water, and then add 0.5 mL of hydrochloric acid with a mass concentration of 37 wt% dropwise. Stir for 120 min to obtain the precursor solution.

[0102] (2) Weigh 1g of polyvinylpyrrolidone (PVP) and dissolve it in 12mL of anhydrous ethanol and stir it evenly; then add the precursor solution obtained in step (1) to it to obtain a precursor sol; electrospin the obtained precursor sol under the conditions of 25kV pressure, 15% relative humidity and room temperature, with a spinning receiving distance of 18cm and a pushing speed of 1mL / h to obtain precursor fibers.

[0103] (3) The precursor fiber obtained in step (2) was dried at 60°C for 12 hours, and then placed in a tube furnace and heated to 500°C at a heating rate of 1°C / min. It was then held at 500°C for 120 minutes to obtain Co-doped Ni3V2O8 electrocatalytic material.

[0104] The X-ray diffraction (XRD) pattern of the Co-doped Ni3V2O8 electrocatalyst material prepared in this comparative example is shown below. Figure 1 As shown. (Through) Figure 1 It can be seen that the diffraction peaks of the obtained product correspond to the standard spectrum of Ni3V2O8 (JCPDS No.74-1484).

[0105] The Co-doped Ni3V2O8 electrocatalytic material prepared in this comparative example is shown in the transmission electron microscope (TEM) image. Figure 8 As shown.

[0106] Application Example 1

[0107] The LSV test method for ORR performance is as follows: A three-electrode system is used, with Co-doped Ni3V2O8 electrocatalyst as the working electrode (rotating disk electrode), platinum wire as the counter electrode, and Hg / HgO electrode as the reference electrode. The electrolyte used is 0.1 MkOH solution. Oxygen is bubbled through the electrolyte for 30 min before the test to saturate it. The scan rate is 10 mV / s.

[0108] Figure 9 LSV curves of ORR for the Co-doped Ni3V2O8 electrocatalytic materials prepared in Examples 1-5 in O2-saturated 0.1M KOH solution at a scan rate of 10mV / s. Figure 10 LSV curves of ORR for electrocatalytic materials prepared in different proportions in O2-saturated 0.1M KOH solution at a scan rate of 10mV / s.

[0109] The half-wave potential is the potential corresponding to half of the limiting diffusion current. It is the most important performance indicator for ORR catalysts, reflecting their intrinsic properties. A more positive half-wave potential indicates better ORR performance. Figure 9 and Figure 10 It can be seen that the Co-doped Ni3V2O8 electrocatalytic material prepared in Example 3 has a more positive half-wave potential than the electrocatalytic material prepared in the comparative example, reaching 0.75V vs. RHE. Therefore, an appropriate amount of Co can maximize the electrocatalytic performance.

Claims

1. A Co-doped Ni3V2O8 electrocatalytic material, wherein the microstructure of the electrocatalytic material is composed of nanofibers made up of mixed Co-doped Ni3V2O8 particles, the morphology is uniform and continuous, the diameter of the nanofibers is 50-120 nm, the length is 1-5 μm, and the aspect ratio is large, which is 10-100. The preparation method of Co-doped Ni3V2O8 electrocatalytic material includes the following steps: (1) Dissolve nickel source, cobalt source, vanadium source and citric acid in deionized water, then add acid solution dropwise and stir to obtain a precursor solution; the nickel source is nickel acetate tetrahydrate or nickel nitrate hexahydrate, the cobalt source is cobalt nitrate hexahydrate, the vanadium source is ammonium metavanadate, the molar ratio of vanadium source to nickel source is (0.3-0.6):(0.3-0.6), the molar ratio of nickel source to cobalt source is (0.6-0.3):(0.01-0.5), the molar amount of vanadium source to the mass ratio of citric acid is (0.3-0.6) mmol:(0.3-0.6) g, and the molar amount of vanadium source to the volume ratio of deionized water is (0.3-0.6) mmol:(2-5) mL. (2) Dissolve polyvinylpyrrolidone PVP in ethanol, and add the precursor solution prepared in step (1) thereto, A precursor sol was obtained; the precursor sol was electrospun at room temperature to obtain precursor fibers; the obtained precursor fibers were dried and calcined to obtain Co-doped Ni3V2O8 electrocatalytic material. 2.The Co-doped Ni 3V 2O 8 electrocatalytic material of claim 1, wherein, In step (1), the acid solution is a hydrochloric acid solution, a nitric acid solution, or an acetic acid solution. The mass concentration of the hydrochloric acid solution is 37 wt%, the mass concentration of the nitric acid solution is 66 wt%, the mass concentration of the acetic acid solution is 99 wt%, the molar amount of the vanadium source is (0.3-0.6) mmol:(0.2-2) mL, and the stirring time is 60-120 min.

3. The Co-doped Ni3V2O8 electrocatalytic material according to claim 1, characterized in that, The weight-average molecular weight of polyvinylpyrrolidone (PVP) in step (2) is 1,000,000 to 1,500,000; the mass-to-volume ratio of polyvinylpyrrolidone (PVP) to ethanol is (0.6-1.6) g: (10-15) mL, and the volume ratio of the precursor solution to ethanol is (2-5): (10-12).

4. The Co-doped Ni3V2O8 electrocatalytic material according to claim 1, characterized in that, In step (2), the voltage of electrospinning is 15-28kV, the relative humidity is 10-35%, the receiving distance is 10-30cm, and the advancing speed is 0.8-1.2mL / h.

5. The Co-doped Ni3V2O8 electrocatalytic material according to claim 1, characterized in that, In step (2), the drying temperature is 40-60℃, the drying time is 12-18h, the calcination temperature is 500℃, and the heating rate is 1-5℃ / min; the calcination time is 120min.

6. The application of the Co-doped Ni3V2O8 electrocatalytic material according to claim 1, applied to the oxygen reduction reaction.

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