VO (OH) 2 / g-C3N4 nano composite material for supercapacitor and preparation method thereof

Abstract

The invention discloses a VO (OH) 2 / g-C3N4 nano composite material for a supercapacitor and a preparation method of the VO (OH) 2 / g-C3N4 nano composite material, and belongs to the technical field of nano composite material preparation. The preparation method comprises the following steps: firstly, preparing g-C3N4 by adopting a calcination method, adding PVP and anhydrous VOSO4 into deionized water, then adding a NaOH solution to adjust the pH value, then adding g-C3N4, uniformly mixing by adopting a magnetic stirrer, then carrying out ultrasonic dispersion, then pouring a mixed solution into a reaction kettle, setting the temperature to be 100 DEG C, and carrying out sealed storage for 48 hours; after the reaction is finished, naturally cooling to the room temperature, cleaning, drying and grinding a product to obtain VO (OH) 2 / g-C3N4 solid powder, wrapping g-C3N4 nanosheets with VO (OH) 2 nanoribbons, and stacking the g-C3N4 nanosheets together to form a staggered network. The VO (OH) 2 / g-C3N4 composite material has a unique low-resistance characteristic, and shows excellent electrochemical performance due to the synergistic effect of a double-layer capacitor and an embedded pseudo capacitor. The prepared nano composite material has good stability and reusability, the preparation process is simple, economical and efficient, and the nano composite material has good application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of nanocomposites, and particularly relates to a simple and novel method for preparing VO(OH) 2 and g-C 3 N 4 composite material. Background Art

[0002] The rapid consumption of fossil fuels and the exacerbation of environmental pollution have made efficient, clean and sustainable energy conversion and storage technologies an urgent need. Compared with batteries, supercapacitors have attracted much attention due to their excellent power output, ultra-long cycle life, easy operation and light weight. The performance of supercapacitors mainly depends on the performance of electrode materials. Therefore, how to develop new supercapacitor electrode materials is of decisive significance. VO(OH) 2 is a new type of vanadium-based material, but there is little research on it at present. Julie et al. first studied the formation mechanism of vanadium-based hydroxides and confirmed that V 4+ hydroxyoxides have important scientific significance and excellent chemical and physical properties in electrochemistry. Therefore, compared with other V-based materials, VO(OH) 2 may have specific chemical and physical properties. In addition, vanadium can enhance bone strength, promote the secretion of growth hormone, thereby promoting the growth and development of children and adolescents, and regulating blood sugar levels.

[0003] Fast charge transfer can improve the activity of non-free radical reactions. Doping, defects, heterojunctions, etc. are the core methods for designing efficient non-free radical catalysts because they can effectively regulate the electronic structure, thereby improving electron transfer and catalytic activity. Graphite carbon nitride (g-C 3 N 4 ) is a typical two-dimensional conjugated polymer material. It has excellent electronic band structure, electron-rich properties and high physical and chemical stability, and is particularly suitable for surface modification and compounding with other materials to improve the catalytic performance of the materials. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a method for a nanocomposite material, and to prepare VO(OH) 2 / g-C 3 N 4 nanocomposite material by using the above method.

[0005] The specific technical solution of the present invention is as follows:

[0006] A vanadium oxyhydroxide and carbon nitride nanocomposite material described in the present invention is composed of VO(OH) 2 coated on g-C 3 N4 The nano-composite structure on it has a chemical composition of VO(OH) 2 / g-C 3 N 4 , and the reactants VOSO 4 and g-C 3 N 4 are in a certain proportion, and the molar ratio of the two is 0.5 - 2.

[0007] For the vanadium oxyhydroxide and carbon nitride nano-composite material described in the present invention, its size is 150 nm - 850 nm, and VO(OH) 2 is compounded on the surface of g-C 3 N 4 .

[0008] A preparation method of a VO(OH) 2 / g-C 3 N 4 nano-composite material, using PVP, anhydrous VOSO 4 , deionized water, sodium hydroxide, and melamine as raw materials. First, weigh 5 g of melamine and place it in a crucible, calcine it at 550 °C for 2 hours, naturally cool it to room temperature, and grind it to obtain g-C 3 N 4 . Then add 0.22 g of PVP to 25 mL of deionized water, and then add 0.82 g of anhydrous VOSO 4 . Adjust the pH value by adding a certain amount of NaOH solution, mix it evenly using a magnetic stirrer, and then add a certain amount of g-C 3 N 4 and ultrasonically disperse it. Then pour the mixed solution into a reaction kettle, seal it and store it at a temperature of 100 °C for 48 hours; after the reaction is completed, naturally cool it to room temperature, wash, dry, and grind the product to obtain VO(OH) 2 / g-C 3 N 4 solid powder.

[0009] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0010] The present invention synthesizes the nano-composite structure for the first time, and realizes the compounding of the VO(OH) 2 / g-C 3 N 4 nano-structure through liquid-solid interface induction, providing a new way for the compounding of hydroxy-oxide nano-materials and g-C 3 N 4 nano-V 2 O 5The composite of materials provides new ideas. The hydrothermal synthesis method is used in this invention, which has simple operation, good repeatability, low cost, and can produce high-yield and high-purity nanocomposites, laying a foundation for the composite research of hydroxy oxide materials and g-C 3 N 4 and further application exploration.

[0011] The prepared VO(OH) 2 / g-C 3 N 4 nanocomposite has a reduced particle size and an increased specific surface area, providing more active sites. Compared with pure VO(OH) 2 , the supercapacitor performance of the composite is improved to a certain extent. Description of the Drawings

[0012] Figure 1 is the XRD pattern of the VO(OH) 2 / g-C 3 N 4 material in Example 1.

[0013] Figure 2 is the SEM image of the VO(OH) 2 / g-C 3 N 4 material in Example 1.

[0014] Figure 3 is the SEM image of the VO(OH) 2 / g-C 3 N 4 material in Example 2.

[0015] Figure 4 is the SEM image of the VO(OH) 2 / g-C 3 N 4 material in Example 3.

[0016] Figure 5 is the TEM image of the VO(OH) 2 / g-C 3 N 4 material in Example 1.

[0017] Figure 6 is the TEM image of the VO(OH) 2 / g-C 3 N 4 material in Example 2.

[0018] Figure 7 is the TEM image of the VO(OH) 2 / g-C 3 N4 TEM image of the material.

[0019] Figure 8 is VO(OH) of Example 4 2 / g-C 3 N 4 TEM image of the material. Detailed implementation mode

[0020] In Example 1, the reactant VOSO 4 and g-C 3 N 4 were prepared with a molar ratio of 1:1 to obtain VO(OH) 2 / g-C 3 N 4 The whole process of the nanocomposite material.

[0021] The first step, the preparation of g-C 3 N 4 : Weigh 5 g of melamine and place it in a crucible. Calcinate it in a muffle furnace at 550 °C with the lid on for 2 hours, and set the heating rate at 5 °C / min. Let it cool naturally to room temperature to obtain a pale yellow solid. Grind it into powder with an agate mortar and set it aside for later use.

[0022] The second step, the preparation of VO(OH) 2 / g-C 3 N 4 The nanocomposite material: Using polyvinylpyrrolidone (PVP), anhydrous VOSO 4 , deionized water, and NaOH as raw materials. Measure 25 mL of deionized water with a graduated cylinder and pour it into a 50 mL beaker. Then weigh 0.2 g of PVP and 0.82 g of anhydrous VOSO 4 and pour them into the beaker containing deionized water. Seal it with plastic wrap and stir it with a magnetic stirrer at room temperature for 30 minutes, then ultrasonically disperse it for 20 minutes until the added anhydrous VOSO 4 and PVP are completely dissolved in deionized water to form a blue transparent solution. Adjust the pH to 4.7 with 0.5 mol / L NaOH, and then pour the prepared g-C 3 N 4 powder into the mixed solution according to the molar ratio of 1:1 with VOSO 4 . Pour the mixed solution into a 25 mL polytetrafluoroethylene inner liner, place the inner liner in the outer shell of the reaction kettle, and then transfer the reaction kettle to a preheated electrothermal constant temperature drying oven at 100 °C and keep it warm for 48 hours. After the reaction is completed, wait for the reaction kettle to cool to room temperature, take out the granular product, put the product into a beaker containing anhydrous ethanol, ultrasonically treat it for 10 minutes, wash it with distilled water and ethanol more than three times, put the centrifuged precipitate into an electrothermal constant temperature drying oven, dry it at 80 °C for 10 hours, and grind it to obtain VO(OH)2 / g-C 3 N 4 Sample powder.

[0023] Figure 1 Shows the XRD pattern of the VO(OH) 2 / g-C 3 N 4 nanocomposite, which is in good agreement with that of VO(OH) 2 (PDF#11-0209).

[0024] Figure 2 Shows the SEM image of the VO(OH) 2 / g-C 3 N 4 nanocomposite, in which g-C 3 N 4 has a flaky structure, VO(OH) 2 has a long strip shape, and VO(OH) 2 is coated on g-C 3 N 4 .

[0025] Example 2, the whole process of adjusting the molar ratio of the reactants VOSO 4 to g-C 3 N 4 to 2:1 to prepare VO(OH) 2 / g-C 3 N 4 nanocomposite.

[0026] The first step, the preparation of g-C 3 N 4 : Weigh 5 g of melamine and place it in a crucible. Calcinate it in a muffle furnace at 550 °C with the lid on for 2 hours, and set the heating rate at 5 °C / min. Let it cool naturally to room temperature to obtain a pale yellow solid. Grind it into powder with an agate mortar and set it aside for later use.

[0027] The second step, the preparation of VO(OH) 2 / g-C 3 N 4 nanocomposite: Using polyvinylpyrrolidone (PVP), anhydrous VOSO 4 , deionized water, and NaOH as raw materials. Measure 25 mL of deionized water with a graduated cylinder and pour it into a 50 mL beaker. Then weigh 0.2 g of PVP and 0.82 g of anhydrous VOSO 4 and pour them into the beaker containing deionized water. Seal it with plastic wrap and stir it with a magnetic stirrer at room temperature for 30 minutes, then ultrasonically disperse it for 20 minutes. The added anhydrous VOSO 4and PVP were completely dissolved in deionized water to form a blue transparent solution. The pH was adjusted to 4.7 with 0.5 mol / L NaOH, and then the prepared g-C 3 N 4 powder was poured into the mixed solution according to the molar ratio of 1:2 with VOSO 4 . The mixed solution was poured into a 25 mL Teflon liner, and the liner was placed in the reactor shell. Then the reactor was transferred to a preheated electrothermal constant temperature drying oven at 100 °C and kept warm for 48 hours. After the reaction, wait for the reactor to cool to room temperature, take out the granular product in the Teflon liner, put the product into a beaker containing anhydrous ethanol, ultrasonicate for 10 minutes, wash it with distilled water and ethanol more than three times, put the centrifuged precipitate into the electrothermal constant temperature drying oven, dry it at 80 °C for 10 hours, and grind it to obtain VO(OH) 2 / g-C 3 N 4 sample powder.

[0028] Figure 3 Figure shows the SEM images of VO(OH) 2 / g-C 3 N 4 nanocomposites, where g-C 3 N 4 shows a flaky structure, VO(OH) 2 shows a long strip shape, and VO(OH) 2 is coated on g-C 3 N 4 , and the amount of VO(OH) 3 N 4 coated on g-C 2 significantly increases.

[0029] Example 3, the whole process of adjusting the molar ratio of reactants VOSO 4 to g-C 3 N 4 to 1:2 to prepare VO(OH) 2 / g-C 3 N 4 nanocomposites.

[0030] The first step, preparation of g-C 3 N 4 : Weigh 5 g of melamine and place it in a crucible. Calcinate it with the lid on in a muffle furnace at 550 °C for 2 hours, and set the heating rate at 5 °C / min. Naturally cool to room temperature to obtain a pale yellow solid, grind it into powder with an agate mortar and set aside.

[0031] The second step, VO(OH) 2 / g-C 3 N4 Preparation of nanocomposite: Using polyvinylpyrrolidone (PVP), anhydrous VOSO 4 , deionized water, and NaOH as raw materials, measure 25 mL of deionized water with a graduated cylinder and pour it into a 50 mL beaker. Then, weigh 0.2 g of PVP and 0.82 g of anhydrous VOSO 4 and pour them into the beaker containing deionized water. Seal the beaker with plastic wrap and stir it with a magnetic stirrer at room temperature for 30 minutes, then ultrasonically disperse it for 20 minutes. The added anhydrous VOSO 4 and PVP are completely dissolved in deionized water to form a blue transparent solution. Adjust the pH to 4.7 with 0.5 mol / L NaOH, and then add the prepared g-C 3 N 4 powder into the mixed solution according to the molar ratio of 2:1 with VOSO 4 . Pour the mixed solution into a 25 mL polytetrafluoroethylene liner, place the liner in the outer shell of the reaction kettle, and then transfer the reaction kettle to a preheated electrothermal constant temperature drying oven at 100 °C and keep it warm for 48 hours. After the reaction is completed, wait for the reaction kettle to cool to room temperature, take out the granular product in the polytetrafluoroethylene liner, put the product into a beaker containing anhydrous ethanol, ultrasonically treat it for 10 minutes, wash it with distilled water and ethanol more than three times, put the centrifuged precipitate into an electrothermal constant temperature drying oven, dry it at 80 °C for 10 hours, and grind it to obtain VO(OH) 2 / g-C 3 N 4 sample powder.

[0032] Example 4, the whole process of preparing VO(OH) 2 / g-C 3 N 4 nanocomposite.

[0033] First step, preparation of g-C 3 N 4 : Weigh 5 g of melamine and place it in a crucible. Calcinate it in a muffle furnace at 550 °C with the lid on for 2 hours, and set the heating rate at 5 °C / min. Let it cool naturally to room temperature to obtain a pale yellow solid, grind it into powder with an agate mortar and set aside.

[0034] Second step, preparation of VO(OH) 2 / g-C 3 N 4 nanocomposite: Using polyvinylpyrrolidone (PVP), anhydrous VOSO 4 , deionized water, and NaOH as raw materials, measure 25 mL of deionized water with a graduated cylinder and pour it into a 50 mL beaker. Then, weigh 0.2 g of PVP and 0.82 g of anhydrous VOSO4 Pour it into a beaker filled with deionized water, seal it with plastic wrap, stir it with a magnetic stirrer at room temperature for 30 minutes, then ultrasonically disperse it for 20 minutes. Add anhydrous VOSO 4 and PVP are completely dissolved in deionized water to form a blue transparent solution. Adjust the pH to 4.8 with 0.5 mol / L NaOH, and then add the prepared g-C 3 N 4 powder into the mixed solution according to the molar ratio of 1:1 with VOSO 4 Pour the mixed solution into a 25 mL Teflon liner, place the liner in the outer shell of the reaction kettle, and then transfer the reaction kettle to a preheated electrothermal constant temperature drying oven at 100 °C and keep it warm for 48 hours. After the reaction is completed, wait for the reaction kettle to cool to room temperature, take out the granular product in the Teflon liner, put the product into a beaker filled with absolute ethanol, ultrasonically treat it for 10 minutes, then wash it with distilled water and ethanol more than three times. Put the centrifuged precipitate into an electrothermal constant temperature drying oven and dry it at 80 °C for 10 hours, and grind it to obtain VO(OH) 2 / g-C 3 N 4 sample powder.

Claims

1. A VO(OH)2 / g-C3N4 nanocomposite material for supercapacitors, characterized in that: It is a composite of VO(OH)2 nanobelts and g-C3N4 nanosheets, with a size of 150nm-850nm, and VO(OH)2 is composited on the surface of g-C3N4.

2. A method for preparing a VO(OH)2 / g-C3N4 nanocomposite material, characterized in that: The synthesis steps are:

1. Preparation of g-C3N4: weigh 5 to 10 g of melamine, place it in a crucible for calcination, and naturally cool it to room temperature to obtain g-C3N4; 2. Preparation of VO(OH)2 / g-C3N4 nanocomposite material: add PVP and anhydrous VOSO4 into deionized water, then add NaOH solution to adjust the pH value, and then add g-C3N4, use a magnetic stirrer to mix evenly, and then ultrasonically disperse it, then pour the mixed solution into a reactor, set the temperature to 100°C, and seal it for 48 hours; after the reaction is completed, naturally cool it to room temperature, wash, dry and grind the product to obtain VO(OH)2 / g-C3N4 solid powder.

3. The method for preparing a VO(OH)2 / g-C3N4 nanocomposite material according to claim 2, characterized in that: The molar ratio of the reactants VOSO4 and g-C3N4 in step 2 is 0.5-2.

4. The method for preparing a VO(OH)2 / g-C3N4 nanocomposite material according to claim 2, characterized in that: In the step 2, the pH value is adjusted to 4.7-4.8 with NaOH solution.

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