CN109904422B - Preparation method and application of vanadium tetrasulfide @ Super P composite powder - Google Patents

Abstract

A preparation method of vanadium tetrasulfide @ Super P composite powder comprises the following steps; weighing 48-52 mg of Super P, adding into 58-62 ml of deionized water, and carrying out ultrasonic treatment for 1.5-2.5 h to obtain a uniformly dispersed black solution A; weighing 0.9-1.1 g of sodium metavanadate and 3.5-3.7 g of thioacetamide, simultaneously adding the sodium metavanadate and the thioacetamide into the solution A, and magnetically stirring for 30-60 min to obtain a solution B; pouring the solution B into a reaction inner liner, sealing, then placing the inner liner in an outer kettle, fixing, placing in a homogeneous reactor, and then reacting at 175-185 ℃ for 23-25 h under the condition of a rotating speed of 5-10 r/min; after the hydrothermal reaction is finished, naturally cooling the reaction kettle to room temperature, taking out a cooled product after the reaction, and collecting the product after alternately cleaning the product by 2-5 times of water and 2-5 times of alcohol; and placing the collected product in a cold well of a freeze dryer for freezing, then placing the frozen product in a tray, covering a sealing cover, vacuumizing to 10-20 Pa, and drying for 12-18 h and then collecting the product.

Description

A kind of preparation method and application of vanadium tetrasulfide@Super P composite powder

technical field

The invention relates to the technical field of vanadium tetrasulfide@SuperP composite powder, in particular to a preparation method and application of a vanadium tetrasulfide@SuperP composite powder.

Background technique

(Rout CS,Kim B-H,et al.J Am ChemSoc.2013,135:8720-8725.)。相似于FeS₂，VS₄来源于天然矿物绿硫钒石，并且S的价态为-1，V的价态为+4。上述结构特性使VS₄在光催化、加氢精制反应、锂离子电池、超级电容器、铝离子电池、镁离子电池等领域得到应用。然而，由于V极易亲氧的特性、反应过程要求精确的S分压以及各种非化学计量比硫化钒的存在，自从1970年VS₄被首次报道以来，关于它们的合成受到了较大的阻碍(Xu X,Jeong S,et al.J Mater Chem A.2014,2:10847-10853.)。并且，对于VS₄的合成通常需要引入模板剂。Sun R等人采用水热法制备了生长于还原石墨烯表面的VS₄(Sun R,Wei Q,et al.ACS Appl Mater Inter.2015,7:20902-20908.)。Li S等人通过灵活的水热法合成了VS₄纳米片堆叠于还原氧化石墨烯上的纳米复合材料(Li S,HeW,et al.Mater Lett.2017,205:52-55.)。Pang Q等人借助CTAB阳离子表面活性剂辅助的水热法制备了均匀的石墨烯片锚定的VS₄纳米颗粒，继而通过改变石墨烯片的加入量，控制了VS₄纳米颗粒的尺寸(Pang Q,Zhao Y,et al.ChemSusChem.2018,11:735-742.)。Wang S等人采用原位氧化石墨烯模板水热法，通过控制氧化石墨烯模板的含量制得了均匀的长方体型VS₄纳米颗粒(Wang S,Gong F,et al.Adv Funct Mater.2018,28:1801806.)。Rout CS等人通过在水热体系中引入氧化石墨烯、羧基化的碳纳米管、富含锁机的芘、苝四甲酸二酐、石墨等碳材料成功得到了它们与VS₄的复合物(Rout CS,Kim B-H,et al.J Am ChemSoc.2013,135:8720-8725.)。然而，在上述已经报道的复合材料中，一部分VS₄没有生长于碳材料表面，仅仅为VS₄与碳材料的复合物，另一部分虽然生长在了碳材料表面，但是分布较为稀疏和无规则，并且VS₄的形貌也不规则均匀。这种不充分且低效的复合使VS₄的高性能并不能得到很好的发挥。As a typical transition metal sulfide, VS ₄ has a one-dimensional chain structure. Among them, two S ₂ ² -groups (four S) tightly surround V and extend along the c direction to form a VS ₄ molecular chain, and a weak van der Waals force is passed between two adjacent VS ₄ molecular chains. connection, the chain spacing can reach

(Rout CS, Kim BH, et al. J Am ChemSoc. 2013, 135:8720-8725.). Similar to FeS ₂ , VS ₄ is derived from the natural mineral viridite, and has a valence state of -1 for S and +4 for V. The above-mentioned structural properties enable VS ₄ to be applied in the fields of photocatalysis, hydrofinishing reactions, lithium-ion batteries, supercapacitors, aluminum-ion batteries, magnesium-ion batteries, etc. However, due to the extremely oxophilic nature of V, the precise S partial pressure required for the reaction process, and the existence of various non-stoichiometric ratios of vanadium sulfide, the synthesis of VS ₄ has received considerable attention since it was first reported in 1970. hindered (Xu X, Jeong S, et al. J Mater Chem A. 2014, 2:10847-10853.). Also, the synthesis of VS ₄ usually requires the introduction of a templating agent. Sun R et al. prepared VS4 grown on the surface of reduced graphene by a hydrothermal method (Sun R, Wei Q, et al. ACS Appl Mater Inter. 2015, ₇ :20902-20908.). Li S et al. synthesized a nanocomposite of VS4 nanosheets stacked on reduced graphene oxide by a flexible hydrothermal method (Li S, _HeW , et al. Mater Lett. 2017, 205:52-55.). Pang Q et al. prepared uniform graphene sheet-anchored _VS4 nanoparticles via CTAB cationic surfactant-assisted hydrothermal method, and then controlled the size of VS4 nanoparticles by changing the amount of graphene sheet added (Pang et al _. Q, Zhao Y, et al. ChemSusChem. 2018, 11:735-742.). Wang S et al. used an in-situ graphene oxide template hydrothermal method to prepare uniform cuboid _- shaped VS4 nanoparticles by controlling the content of graphene oxide template (Wang S, Gong F, et al. Adv Funct Mater. 2018, 28 :1801806.).) Rout CS et al. successfully obtained their composites with VS ₄ by introducing carbon materials such as graphene oxide, carboxylated carbon nanotubes, pyrene rich in interlocks, perylene tetracarboxylic dianhydride, and graphite into the hydrothermal system ( Rout CS, Kim BH, et al. J Am ChemSoc. 2013, 135:8720-8725.). However, in the above-mentioned composite materials, a part of VS ₄ did not grow on the surface of the carbon material, but was only a composite of VS ₄ and the carbon material, and the other part grew on the surface of the carbon material, but the distribution was sparse and irregular. And the morphology of VS ₄ is also irregular and uniform. This insufficient and inefficient compounding prevents the high performance of VS ₄ from being used very well.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies of the above-mentioned prior art, the object of the present invention is to provide a preparation method and application of a vanadium tetrasulfide@Super P composite powder, the present invention uses water as a solvent, and uses sodium metavanadate and thioacetamide respectively It is vanadium source and sulfur source, and Super P carbon source is introduced. By controlling their concentration and ratio, reaction temperature, reaction time, filling ratio and other parameters, a one-step template-free hydrothermal method is realized on the surface of Super P nanospheres. In situ generation of flexible entangled VS ₄ nanorod structures, this method has a simple reaction process, low temperature, easy control, and does not require large-scale equipment and harsh reaction conditions, and can directly realize the formation of VS ₄ in one reaction process. In situ winding of nanosphere surfaces. When the above products are applied as anode materials and photo/electrocatalysts for Li/Na-ion batteries, they can exhibit excellent electrochemical and catalytic properties.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A preparation method of vanadium tetrasulfide@Super P composite powder, comprising the following steps;

Step 1: Weigh 48-52 mg of Super P into 58-62 ml of deionized water, and ultrasonicate for 1.5-2.5 hours to obtain a uniformly dispersed black solution A;

Step 2: Weigh 0.9-1.1 g of sodium metavanadate and 3.5-3.7 g of thioacetamide and add them to solution A at the same time, and magnetically stir for 30-60 min to obtain solution B;

Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it and place it in the homogeneous reactor, and then under the condition of the rotating speed of 5-10 r/min, at 175-185 React at ℃ for 23-25h;

Step 4: After the hydrothermal reaction is completed, the reactor is naturally cooled to room temperature, and then the cooled product after the reaction is taken out, and the product is collected after 2 to 5 times of alternate cleaning with water and 2 to 5 times of alcohol;

Step 5: Place the collected product in the cold well of the freeze dryer for freezing, then place the frozen product in a tray, cover with a sealing cover, evacuate to 10-20 Pa, and collect the product after drying for 12-18 hours, that is, Vanadium tetrasulfide@Super P composite powder can be obtained.

In the first step, the ultrasonic power is 400-600W, and it is carried out at normal temperature.

In the second step, the rotating speed of the magnetic stirring is 400-600 r/min, and it is carried out at normal temperature.

In the third step, the filling ratio of solution B poured into the reaction liner is 58-62%.

In the step 4, alternate cleaning with water and alcohol is mainly performed by means of suction filtration or centrifugation, and collection is also mainly carried out by means of suction filtration or centrifugation.

The freezing conditions in the fifth step are: -60 to -40° C., and freeze for 2 to 5 hours.

Before the product in step 5 is put into the tray for drying, it is sealed with a plastic wrap, and the plastic wrap is punctured to ensure that it is fully dried under low pressure conditions.

The composite powder is composed of uniform submicrospheres with a diameter of about 200nm, and the submicrospheres have a core-shell structure, wherein the core is Super P with a diameter of about 30nm, and the shell is wound by flexible VS ₄ nanorods. , and the _VS4 nanorods have high crystallinity and orientation along the (110) plane direction.

The combination between the vanadium tetrasulfide and Super P is a chemical bond rather than a physical bond.

The application of vanadium sulfide@Super P composite powder can be in the field of Li/Na-ion battery or in the field of photo/electrocatalysis.

Beneficial effects of the present invention:

(1) the present invention directly synthesizes the final composite structure by one-step template-free hydrothermal reaction, thus has a low synthesis temperature, a simple synthesis path, and does not require large-scale equipment and harsh reaction conditions;

(2) vanadium source used in the present invention is sodium metavanadate, sulfur source is thioacetamide, solvent is water, these three kinds of materials are common raw materials, cheap and easy to obtain and low cost, the whole reaction yield is high, easy to control It is environmentally friendly, the product does not need post-processing, and can be suitable for large-scale production;

(3) when the product prepared by the present invention is used as a negative electrode material for a lithium/sodium ion battery and a photo/electrocatalyst, it can show excellent performance;

( ₄ ) The present invention makes full use of the adsorption of vanadium source and sulfur source on the surface of Super P by strictly controlling parameters such as the concentration and ratio of vanadium source and sulfur source, reaction temperature, reaction time, filling ratio, etc. The surface of P nanospheres is uniformly nucleated and grown based on it, thus forming a composite structure in which _VS4 nanorods are wound on Super P nanospheres in situ;

(5) The amount of Super P added plays a key role in the formation of the uniform VS ₄ nanorod wound Super P nanosphere structure. The introduction of too much and too little Super P can not provide suitable sites for the nucleation and growth of VS ₄ , so a uniform composite structure cannot be obtained;

(6) The reaction time plays a key role in the formation of the uniform VS4 nanorod _- wound Super P nanosphere structure. Too long and too short reaction time are not conducive to the construction of a better VS ₄ nanorod wound Super P nanosphere structure;

(7) In the process of synthesizing vanadium tetrasulfide@Super P in the present invention, no template agent or surfactant is introduced, and the entire in-situ growth process uses the abundant oxygen-containing functional groups on the surface of Super P as active sites. The reaction is simple, easy to control, efficient and low cost;

(8) During the in-situ growth of VS ₄ on the surface of Super P nanospheres, the synergistic effect of the abundant oxygen-containing functional groups on the surface of Super P and the temperature field and pressure field generated by hydrothermal make the formation between VS ₄ and Super P. chemical bonding;

(9) The composite product prepared by the present invention has a unique composite structure, wherein the VS ₄ wound on the outer surface of Super P mainly plays the role of storing Na ⁺ , and Super P can not only provide a good conductive path for the charging and discharging process, but also The volume change of VS ₄ during charging and discharging can also be suppressed. VS ₄ fully exposes the crystal structure aligned along the (110) crystal plane. Since the (110) crystal plane has the largest interplanar spacing, it acts as a channel for metal ions to enter and exit between chains, which is very beneficial to the storage of metal ions between chains of VS ₄ . and transmission. Under the synergistic effect of these structural advantages, vanadium tetrasulfide@Super P can exhibit excellent cycling performance and rate capability.

Description of drawings

Fig. 1 is the X-ray diffraction pattern of the product prepared in Example 1 of the present invention.

Figure 2 is a low magnification scanning electron microscope image of the product prepared in Example 1 of the present invention.

3 is a high-magnification scanning electron microscope image of the product prepared in Example 1 of the present invention.

4 is a transmission electron microscope image of the product prepared in Example 1 of the present invention.

FIG. 5 is a scanning TEM image of the product prepared in Example 1 of the present invention.

6 is a low-magnification high-resolution transmission electron microscope image of the product prepared in Example 1 of the present invention.

7 is a high-magnification and high-resolution transmission electron microscope image of the product prepared in Example 1 of the present invention.

8 is a scanning electron microscope image of the product obtained after reducing the amount of Super P added in Example 1 of the present invention to 20 mg.

FIG. 9 is a scanning electron microscope image of the product obtained by increasing the amount of Super P in Example 1 of the present invention to 80 mg.

Figure 10 is a scanning electron microscope image of the product obtained after shortening the reaction time in Example 1 of the present invention to 12h.

Detailed ways

The present invention will be described in further detail below in conjunction with the examples.

Example 1:

Step 1: Weigh 50mg of Super P into 60ml of deionized water, ultrasonicate for 2h, and the ultrasonic power is 400-600W to obtain a uniformly dispersed black solution A.

Step 2: Weigh 1.0 g of sodium metavanadate and 3.6 g of thioacetamide and add them to solution A at the same time, and magnetically stir at a speed of 400-600 r/min for 50 min to obtain solution B.

Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it and place it in a homogeneous reactor with a filling ratio of 59%. React at 180°C for 24h.

Step 4: After the hydrothermal reaction is completed, the reaction kettle is naturally cooled to room temperature, and then the cooled product after the reaction is taken out, and the product is collected after 3 times of alternate cleaning with water and 3 times of alcohol.

Step 5: Put the collected product in the cold well of the freeze dryer for freezing, the freezing conditions are: -50°C, freeze for 4 hours, then place the frozen product in a tray, cover with a sealing cover, and evacuate to 20Pa, The product was collected after drying for 18 h, and the vanadium tetrasulfide@Super P composite powder was obtained.

Example 2:

Step 1: Weigh 48mg of Super P into 58ml of deionized water, ultrasonicate for 1.5h, and the ultrasonic power is 400W to obtain a uniformly dispersed black solution A;

Step 2: Weigh 0.9g of sodium metavanadate and 3.5g of thioacetamide and add them to solution A at the same time, magnetic stirring for 30min at a speed of 400r/min, to obtain solution B;

Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it in a homogeneous reactor with a filling ratio of 58%. React at 175°C for 23h;

Step 4: the hydrothermal reaction is completed, the reactor is naturally cooled to room temperature, and then the cooled product after the reaction is taken out, and the product is collected after 2 times of water and 2 times of alcohol alternate cleaning;

Step 5: Put the collected product in the cold well of the freeze dryer for freezing, the freezing conditions are: -60°C, freeze for 2 hours, then place the frozen product in a tray, cover with a sealing cover, and evacuate to 10Pa, The product was collected after drying for 12 h, and the vanadium tetrasulfide@Super P composite powder was obtained.

Example 3:

Step 1: Weigh 52mg of Super P and add it to 62ml of deionized water, ultrasonicate for 2.5h, and the ultrasonic power is 600W to obtain a uniformly dispersed black solution A;

Step 2: Weigh 1.1g of sodium metavanadate and 3.7g of thioacetamide and add them into solution A at the same time, and magnetic stirring for 60min at a rotational speed of 600r/min to obtain solution B;

Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it in a homogeneous reactor with a filling ratio of 62%, and then under the condition of 10r/min rotating speed, React at 185°C for 25h;

Step 4: After the hydrothermal reaction is completed, the reactor is naturally cooled to room temperature, then the cooled product after the reaction is taken out, and the product is collected after 5 times of alternate cleaning with water and 5 times of alcohol;

Step 5: Place the collected product in the cold well of the freeze dryer for freezing. The freezing conditions are: -40°C, freeze for 5 hours, then place the frozen product in a tray, cover with a sealing cover, and evacuate to 20Pa, The product was collected after drying for 18 h, and the vanadium tetrasulfide@Super P composite powder was obtained.

Example 4:

Step 1: Weigh 50mg of Super P and add it to 60ml of deionized water, the ultrasonic power is 500W, and ultrasonic for 2h to obtain a uniformly dispersed black solution A;

Step 2: Weigh 1g of sodium metavanadate and 3.6g of thioacetamide and add them to solution A at the same time, magnetic stirring for 45min at a rotational speed of 500r/min, to obtain solution B;

Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it in a homogeneous reactor with a filling ratio of 60%, and then under the condition of 8r/min rotating speed, React at 180°C for 24h;

Step 4: After the hydrothermal reaction is completed, the reactor is naturally cooled to room temperature, then the cooled product after the reaction is taken out, and the product is collected after 3 times of alternate cleaning with water and 3 alcohols;

Step 5: Freeze the collected product in the cold well of the freeze dryer. The freezing conditions are: -50°C, freeze for 3 hours, then place the frozen product in a tray, cover with a sealing cover, and evacuate to 15Pa, The product was collected after drying for 15 h, and the vanadium tetrasulfide@Super P composite powder was obtained.

As shown in Figure 1, all diffraction peaks can be well matched to the standard card PDF#72-1294 of VS ₄ . Due to the low content of Super P and low crystallinity, the diffraction peaks of Super P cannot be observed in Figure 1.

As shown in Fig. 2, vanadium tetrasulfide@Super P is composed of uniform submicrospheres.

As shown in Fig. 3, the diameter of the obtained submicrospheres is about 200 nm, and the outer part is wound by flexible _VS4 nanorods.

As shown in Fig. 4, the obtained submicrospheres exhibited a core-shell structure, and the shells were wound by flexible _VS4 nanorods.

As shown in Figure 5, the obtained submicrospheres exhibited a core-shell structure, in which the core was Super P with a diameter of about 30 nm, and the shell was wound by flexible _VS4 nanorods.

As shown in Figure 6. The regular lattice fringes of the _VS4 nanorods can be clearly seen from the figure, indicating its high crystallinity.

As shown in Figure 7. The (110) plane lattice fringes of the _VS4 nanorods can be clearly seen from the figure, indicating its crystalline structure oriented along the (110) plane direction.

As shown in FIG. 8 , the scanning electron microscope image of the product obtained after the addition of Super P in Example 1 of the present invention was reduced to 20 mg. From the figure, many small VS ₄ particles that are not assembled into nanorods can be observed, indicating that VS ₄ and Super P are not well-complexed together.

As shown in FIG. 9 , the scanning electron microscope image of the product obtained after the addition of Super P in Example 1 of the present invention was increased to 80 mg. A lot of small VS ₄ particles that are not assembled into nanorods are also observed from the figure, indicating that VS ₄ and Super P are also not well-complexed together.

Figure 10 is a scanning electron microscope image of the product obtained after shortening the reaction time in Example 1 of the present invention to 12h. It can be seen from the figure that there are many small VS ₄ particles that are not assembled into nanorods, indicating that VS ₄ and Super P do not composite well together in a short period of time.

Claims (9)

1. a preparation method of vanadium tetrasulfide@Super P composite powder, is characterized in that, comprises the following steps; Step 1: Weigh 48~52mg of Super P into 58~62ml deionized water, and ultrasonicate for 1.5~2.5h to obtain a uniformly dispersed black solution A; Step 2: Weigh 0.9~1.1g of sodium metavanadate and 3.5~3.7g of thioacetamide and add them to solution A at the same time, stir magnetically for 30~60min to obtain solution B; Step 3: Pour the solution B into the reaction lining and seal it, then install the lining in the outer kettle and fix it and place it in the homogeneous reactor, and then under the condition of the rotating speed of 5~10r/min, at 175~185 React at ℃ for 23~25h; Step 4: After the hydrothermal reaction ends, the reactor is naturally cooled to room temperature, and then the cooled product after the reaction is taken out, and the product is collected after 2 to 5 times of alternate cleaning with water and 2 to 5 times of alcohol; Step 5: Place the collected product in the cold well of the freeze dryer for freezing, then place the frozen product in a tray, cover with a sealing cover, evacuate to 10~20Pa, and collect the product after drying for 12~18h, that is, Vanadium tetrasulfide@SuperP composite powder can be obtained. 2. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, in described step 1, ultrasonic power is 400～600W, and carries out under normal temperature. 3. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, in described step 2, the rotating speed of magnetic stirring is 400～600r/min, and carries out at normal temperature. 4. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, in described step 3, the filling ratio that solution B is poured into reaction lining is 58～62%. 5. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, in described step 4, water and alcohol alternately clean mainly by the mode of suction filtration or centrifugal, collect also Mainly by suction filtration or centrifugation. 6. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, the freezing condition of described step 5 is: -60～-40 ℃, freezing 2～5h. 7. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, before described step 5 product is put into tray and is dried, it is sealed with plastic wrap, and Puncture the plastic wrap to ensure adequate drying under low pressure conditions. 8. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, described composite powder is made up of submicrospheres with uniform diameter of about 200nm, submicron The spheres exhibit a core-shell structure, in which the core is Super P with a diameter of about 30 nm, and the shell is wound by flexible _{VS4 nanorods} with high crystallinity and orientation along the (110) crystal plane. Orientation arrangement. 9. the preparation method of a kind of vanadium tetrasulfide@Super P composite powder according to claim 1, is characterized in that, the combination between described vanadium tetrasulfide and Super P is chemical bond combination, rather than physical combination.

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