CN113481656B - Preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric - Google Patents

Abstract

The invention discloses a preparation method of a high-purity vanadium pentoxide nanofiber nonwoven fabric, which belongs to the technical field of nanomaterials. The preparation method of the present invention mainly lies in the regulation of crystal nucleation and growth in the synthesis process, namely adding ammonium metavanadate to a hydrochloric acid solution, stirring and dissolving under normal temperature conditions, and then performing a hydrothermal reaction at a certain temperature, and then conducting a hydrothermal reaction at a certain temperature. Remove and collect the vanadium pentoxide nanofiber non-woven fabric. The vanadium pentoxide nanofiber non-woven fabric prepared by the invention has a purity of ≥99.9% and a thickness of 0.01-10 mm, wherein the vanadium pentoxide nanofiber has a diameter of 10-5000 nm; the raw materials used in the preparation method of the present invention are simple and inexpensive, and the The production cost is reduced; the adopted one-step process is easy to operate, convenient for large-scale production in factories, and can effectively solve the complex problem of the existing method for preparing vanadium pentoxide nanofiber non-woven fabrics.

Description

Preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric

technical field

The invention belongs to the technical field of nanomaterials, and in particular relates to a preparation method of a high-purity vanadium pentoxide nanofiber nonwoven fabric.

Background technique

Vanadium pentoxide (V ₂ O ₅ ) is the most important vanadium functional material and intermediate, and has important application value in the fields of special steel, glass ceramic industry colorant, sulfuric acid petrochemical industry catalyst and electrochemical energy storage material. One-dimensional vanadium pentoxide nanowires have unique effects on the preparation of flexible electronic devices and in catalysis or mechanical reinforcement due to their large specific surface area, many active sites and good mechanical flexibility. At present, the methods for synthesizing one-dimensional vanadium pentoxide nanomaterials mainly include hydrothermal method (including hydrothermal recrystallization), template method, sol-gel method and precipitation method, as well as some other physical methods.

Vanadium pentoxide nanowire woven non-woven fabrics have more extensive and special applications due to their special macroscopic morphology and microstructure, such as catalysis, energy storage and multi-level structure materials, but direct preparation of large-area vanadium pentoxide nanofibers is not feasible. Textile has not yet been reported. Theoretically, vanadium pentoxide nanofiber nonwovens can be prepared by suction filtration of vanadium pentoxide nanowires or electrospinning vanadium precursor composites and calcined to obtain vanadium pentoxide fiber nonwovens with a larger area. However, these methods are more complicated in practical application, and the cost is high. Therefore, it is necessary to develop a preparation method of vanadium pentoxide nanofiber non-woven fabric with simple procedure and low cost at this stage.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is that the existing method for preparing vanadium pentoxide nanofiber non-woven fabric is relatively complicated.

The technical solution adopted by the present invention to solve the technical problem is: a method for preparing a high-purity vanadium pentoxide nanofiber nonwoven fabric, comprising the following steps: mixing ammonium metavanadate and a hydrochloric acid solution with a concentration of 2-200 g/L according to 0.5 -10:100 mass ratio mixing, fully dissolved, put into a reaction vessel, heated to 100-250 ℃ in a closed system for 6-72 hours, and then peeled off from the inner wall of the reaction vessel to obtain vanadium pentoxide nanofiber non-woven fabric.

Further, the concentration of the hydrochloric acid solution is 10-100 g/L, and the ammonium metavanadate and the hydrochloric acid solution are mixed in a mass ratio of 1-3:100.

Further, the ammonium metavanadate of the present invention can use industrial ammonium metavanadate waste material, and after dissolving the ammonium metavanadate, it is necessary to maintain clarity without any interference such as suspended particles, and if necessary, undergo sedimentation or filtration; the hydrochloric acid solution can use industrial hydrochloric acid. .

Further, it is put into a reaction vessel and heated to 180-220° C. in a closed system to react for 12-36 hours.

Further, the reaction vessel is a hydrothermal reactor with a high temperature resistant lining or other reaction vessel lined with a higher temperature resistant inert material.

Further, the reaction vessel is a commercially available polytetrafluoroethylene-lined hydrothermal reactor.

Furthermore, the length-diameter ratio of the inner lining of the reaction vessel is greater than or equal to 1.5.

After the above-mentioned hydrothermal reaction is completed, a non-woven fabric is obtained on the inner wall of the reaction kettle, and is cut with scissors during the peeling process, so that it is completely peeled off.

After the vanadium pentoxide nanofiber non-woven fabric is obtained above, the structure of the non-woven fabric is optimized through the steps of washing, drying and high-temperature annealing to ensure the flatness, thickness and strength of the fiber non-woven fabric.

Further, washing with deionized water and ethanol, drying at a temperature of 50-150°C for 2-48h, and annealing at a temperature of 300-600°C for 1-12h.

Further, drying is performed at a temperature of 80-110°C for 10-24h, and annealing at a temperature of 400-550°C for 2-4h.

The above-mentioned vanadium pentoxide nanofiber nonwoven has a purity of ≥99.9% and a thickness of 0.01-10 mm, wherein the vanadium pentoxide nanofiber has a diameter of 10-5000 nm.

The beneficial effects of the present invention are as follows: the present invention adopts ammonium metavanadate and hydrochloric acid solution to stir and dissolve under normal temperature conditions, and then conduct hydrothermal reaction at a temperature of 100-250 DEG C in a closed system to control the vanadium pentoxide nanofibers in Nucleation, stable growth and staggered arrangement of fibers on the inner wall surface of the reactor.

The reaction process of the present invention should be kept stable and not subject to vibration, and its nucleation/adsorption on the inner surface of the reaction kettle should be maintained. When the temperature of the kettle wall is high, it will preferentially nucleate and grow under the action of the temperature gradient, and gradually accumulate to form a fiber staggered structure; and the high reaction temperature and long reaction time are conducive to the reaction and increase the chemical reaction limit; the concentration of the mixed solution is large, and the fibers accumulate. A large number of layers is beneficial to increase the thickness or strength of the fiber cloth; in the present invention, the lining aspect ratio of the reaction vessel is preferably ≥1.5, which can increase the surface deposition ratio and reduce or avoid bulk reaction or excessive deposition at the bottom.

The vanadium pentoxide nanofiber non-woven fabric prepared by the invention has a purity of ≥99.9% and a thickness of 0.01-10 mm, wherein the vanadium pentoxide nanofiber has a diameter of 10-5000 nm. The raw materials used in the method of the invention are cheap, the production process only needs one step/one pot, the process operation is convenient and simple, and it is convenient for large-scale preparation, and the prepared vanadium pentoxide nanofiber non-woven fabric can be used for catalysts, electrochemical energy storage and special alloys, etc.

Description of drawings

Fig. 1 is the macroscopic topography of the original vanadium pentoxide nanofiber non-woven fabric obtained in the embodiment.

Figure 2 is a microscopic topography (×200) of the vanadium pentoxide nanofiber nonwoven fabric obtained in the embodiment.

FIG. 3 is a microscopic topography (×1000) of the vanadium pentoxide nanofiber nonwoven fabric obtained in the embodiment.

Figure 4 is a microscopic topography (×3000) of the vanadium pentoxide nanofiber nonwoven fabric obtained in the embodiment.

FIG. 5 is a microscopic topography (×10000) of the vanadium pentoxide nanofiber nonwoven fabric obtained in the embodiment.

FIG. 6 is the XRD pattern of the original vanadium pentoxide nanofiber non-woven fabric obtained in the embodiment and the high-temperature calcination XRD pattern thereof.

Fig. 7 is the element analysis EDS figure selection point of the vanadium pentoxide nanofiber nonwoven fabric obtained in the embodiment.

Fig. 8 is the elemental analysis EDS chart of the vanadium pentoxide non-woven fabric obtained in the embodiment.

Detailed ways

The technical solution of the present invention can be specifically implemented in the following manner.

The preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric includes the following steps: after mixing ammonium metavanadate and a hydrochloric acid solution with a concentration of 2-200g/L according to a mass ratio of 0.5-10:100, put it into a reaction The container is heated to 100-250 DEG C in a closed system to react for 6-72 hours, and then peeled off from the inner wall of the reaction container to obtain a vanadium pentoxide nanofiber nonwoven fabric.

The growth time, temperature and the concentration of the mixed solution are properly matched, which is conducive to the reaction and improves the chemical reaction limit. Therefore, it is preferable that the concentration of the hydrochloric acid solution is 10-100g/L, and the ammonium metavanadate and the hydrochloric acid solution are in accordance with 1-3:100 The mass ratio of the mixture; put into the reaction vessel and heated to 180-220 ℃ in a closed system to react for 12-36h.

In order to reduce the production cost and reduce the entry of impurities simultaneously, it is preferred that the ammonium metavanadate of the present invention can use industrial ammonium metavanadate waste, and after dissolving the ammonium metavanadate, it is necessary to maintain clarity without interference such as suspended particles. Sedimentation or filtration; hydrochloric acid solution can use industrial hydrochloric acid.

In order to achieve better experimental results, it is therefore preferred that the reaction vessel is a hydrothermal reactor with a high temperature resistant lining or other reaction vessels lined with a higher temperature resistant inert material; more preferably, the The reaction vessel is a commercially available polytetrafluoroethylene-lined hydrothermal reactor.

In order to reduce or avoid bulk reaction or excessive deposition at the bottom, it is therefore preferred that the length-diameter ratio of the inner lining of the reaction vessel is greater than or equal to 1.5.

After the above-mentioned hydrothermal reaction is completed, a non-woven fabric is obtained on the inner wall of the reaction kettle, and is cut with scissors during the peeling process, so that it is completely peeled off.

In order to obtain a non-woven fabric with better flatness, thickness and strength, it is preferred that after the vanadium pentoxide nanofiber non-woven fabric is obtained above, the structure of the non-woven fabric is optimized through the steps of washing, drying and high temperature annealing, Ensure the flatness, thickness and strength of the fiber non-woven fabric; preferably, wash with deionized water and ethanol, dry at 50-150°C for 2-48h, and anneal at 300-600°C for 1- 12h; more preferably, drying at a temperature of 80-110°C for 10-24h, and annealing at a temperature of 400-550°C for 2-4h.

The above-mentioned vanadium pentoxide nanofiber nonwoven has a purity of ≥99.9% and a thickness of 0.01-10 mm, wherein the vanadium pentoxide nanofiber has a diameter of 10-5000 nm.

The technical solutions and effects of the present invention will be further described below through practical examples.

Example

The present invention provides a group of embodiments of preparing high-purity vanadium pentoxide nanofiber non-woven fabric by the method of the present invention. The high-purity vanadium pentoxide nano-fiber non-woven fabric is prepared by a one-step hydrothermal synthesis method, and the steps include:

a. Mix the ammonium metavanadate solution with the hydrochloric acid solution whose concentration is 30g/L according to the mass ratio of 3:100;

b. Pour the mixed solution obtained in step a into a tetrafluoroethylene-lined hydrothermal reaction kettle, and heat it to 150° C. for 24 hours in a closed system to obtain the original vanadium pentoxide nanofiber non-woven fabric;

c. Wash the original vanadium pentoxide nanofiber non-woven fabric obtained after the reaction with deionized water and ethanol for several times, and then place it in an oven to dry at 60°C;

d. The non-woven fabric after drying is placed in a muffle furnace for heat treatment at 500° C. for 4 hours to obtain a vanadium pentoxide nanofiber non-woven fabric with higher crystallinity.

The macroscopic topography of the original vanadium pentoxide nanofiber non-woven fabric obtained in the step b of the embodiment is shown in Figure 1. It can be seen from the figure that the fiber cloth is yellow, flexible and foldable, and the size can be adjusted according to the inner wall size of the reactor. Can be cut to various shapes.

The vanadium pentoxide nanofiber non-woven fabric obtained in the step d of the embodiment is tested, and the microscopic topography diagrams under different microscopic magnifications are shown in Figures 2-5: Figure 2 is the vanadium pentoxide nanofiber obtained in the embodiment. The microscopic topography of the fiber non-woven fabric (×200), it can be seen from the figure that the fiber fabric has shrinkage wrinkles after high temperature annealing, showing the shape of a wrinkled non-woven fabric; Figure 3 is the vanadium pentoxide nanofiber non-woven fabric obtained in the embodiment. The microscopic topography of the cloth (×1000), it can be seen from the figure that the fiber cloth is composed of non-oriented fine fibers; Figure 4 is the microscopic topography of the vanadium pentoxide nanofiber non-woven fabric obtained in the example (×3000), It can be seen from the figure that the fiber cloth is composed of non-oriented submicron fibers, which are dense and uniform; The fiber cloth is composed of nanofibers and has a high aspect ratio.

The XRD pattern of the original vanadium pentoxide nanofiber non-woven fabric obtained in the Example and its high-temperature calcination XRD pattern are shown in Figure 6. As can be seen from the figure, the non-woven fabric is a vanadium pentoxide crystal structure, and the crystal form before and after high temperature annealing No change, but the crystallinity improved after annealing.

Elemental analysis is carried out on the vanadium pentoxide nanofiber non-woven fabric obtained in the embodiment. The selected points of the EDS diagram are shown in Figure 7, and the elemental analysis EDS diagram is shown in Figure 8. It can be seen from Figure 7 that the characteristics of the non-woven nanofibers are shown in Figure 7. Obviously, different regions are selected to characterize the material element distribution; as can be seen from Figure 8, the selected regions are composed of vanadium (V) and oxygen (O); EDS elemental analysis data for the vanadium pentoxide nanofiber non-woven fabric obtained in the embodiment are as follows: As shown in Table 1, it can be seen from Table 1 that the V:O element molar ratio is basically around 2:5, that is, the obtained product is a vanadium pentoxide nanofiber non-woven fabric with a purity of ≥99.9%.

Table 1 Elemental analysis data

element line type apparent concentration k ratio Wt% Wt%Sigma Standard sample label O K line system 17.54 0.05902 44.30 0.78 SiO2 V K line system 74.62 0.74623 55.70 0.78 V Total: 100.00

Claims (7)

1. the preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric is characterized in that comprising the steps: be that the hydrochloric acid solution of 30g/L of ammonium metavanadate and concentration is mixed according to the mass ratio of 3: 100, after fully dissolving , put it into a reaction vessel, heated to 150° C. for 24 hours in a closed system, and then peeled off the inner wall of the reaction vessel to obtain a vanadium pentoxide nanofiber nonwoven fabric. 2. the preparation method of high-purity vanadium pentoxide nanofiber nonwoven fabric according to claim 1, is characterized in that: described reaction vessel is the hydrothermal reactor with high temperature resistant inner lining or other high temperature resistant Reaction vessel lined with inert material. 3. The preparation method of high-purity vanadium pentoxide nanofiber nonwoven fabric according to claim 2, characterized in that: the length-diameter ratio of the inner lining of the reaction vessel is greater than or equal to 1.5. 4. the preparation method of high-purity vanadium pentoxide nanofiber nonwoven fabric according to claim 1, is characterized in that: after obtaining vanadium pentoxide nanofiber nonwoven fabric, through the steps of washing, drying, high temperature annealing Optimize the structure of the non-woven fabric. 5. the preparation method of high-purity vanadium pentoxide nanofiber nonwoven fabric according to claim 4, is characterized in that: using deionized water and ethanol washing, drying 2-48h at the temperature of 50-150 ℃, Anneal at a temperature of 300-600°C for 1-12h. 6. The preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric according to claim 5, characterized in that: drying at a temperature of 80-110°C for 10-24h, at a temperature of 400-550°C Annealed for 2-4h. 7. The preparation method of high-purity vanadium pentoxide nanofiber non-woven fabric according to claim 1, characterized in that: the purity of the vanadium pentoxide nanofiber non-woven fabric is greater than or equal to 99.9%, and the thickness is 0.01-10mm, The diameter of vanadium pentoxide nanofibers is 10-5000nm.

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