阅读说明：本技术 一种M位掺杂钒系MXene的制备方法 (Preparation method of M-site vanadium-doped MXene ) 是由 刘毅 罗威 郭守武 朱建锋 张利锋 霍京浩 王晓飞 于 2020-06-12 设计创作，主要内容包括：本发明公开了一种M位掺杂钒系MXene的制备方法,将金属粉、铝粉、碳粉和熔盐按一定比例混合制成粉料；随后将粉料置于研钵中加入研磨液后空气条件下研磨3-8min使其初步混合,接着转入球磨罐中球磨3～6h,得到粉体,后将粉体置于磁舟中进行高温气氛烧结,得到M位掺杂MAX相粉体,将其与刻蚀剂按照一定比例混合,随后在20-35℃下磁力搅拌12-36h,完成后清洗、离心分离、烘干得到M位掺杂V<Sub>2</Sub>CT<Sub>x</Sub>MXene。本发明制备的MXene粉体材料具有较高纯度,杂化位点多等特点,可根据工况需求进行结构微调,在等电化学领域具有广泛应用前景。(The invention discloses a preparation method of M-site vanadium-doped MXene, which comprises the following steps of mixing metal powder, aluminum powder, carbon powder and molten salt according to a certain proportion to prepare powder; then placing the powder into a mortar, adding grinding fluid, grinding for 3-8min under the air condition to preliminarily mix the powder, then transferring the powder into a ball milling tank for ball milling for 3-6h to obtain powder, then placing the powder into a magnetic boat for high-temperature atmosphere sintering to obtain M-site doped MAX phase powder, mixing the M-site doped MAX phase powder with an etching agent according to a certain proportion, then magnetically stirring for 12-36h at 20-35 ℃, cleaning, centrifugally separating and drying to obtain M-site doped V phase powder 2 CT x MXene. The MXene powder material prepared by the method has the characteristics of high purity, multiple hybridization sites and the like, can be subjected to structure fine adjustment according to working condition requirements, and has wide application prospects in the field of electrochemistry and the like.)

1. A preparation method of M-site vanadium-doped MXene is characterized by comprising the following steps:

the method comprises the following steps: mixing metal powder, aluminum powder, carbon powder and mixed molten salt to prepare powder; grinding the powder to preliminarily mix the powder, then carrying out ball milling to obtain powder, and then sintering the powder in high-temperature atmosphere to obtain M-bit doped MAX phase powder which is recorded as MAX phase powder; the metal powder is three-phase mixed powder formed by V powder and any two of Ti powder, Cr powder, Mo powder, Zr powder and Nb powder, and the molar ratio of the V powder in the three-phase mixed powder is more than 50 percent; the mixed molten salt is a mixture of sodium chloride and potassium chloride in any proportion;

step two: mixing MAX phase powder and etchant, stirring at 20-35 deg.C for 12-36h, cleaning, centrifuging, and oven drying to obtain M-site doped V₂CT_xMXene。

2. The method for preparing the M-site vanadium-doped MXene according to claim 1, wherein the molar ratio of the metal powder, the aluminum powder, the carbon powder and the mixed molten salt in the step one is (2-2.3): (1.05-1.2): (1-1.1): (5-25).

3. The method for preparing the MXene doped with vanadium at M position according to claim 1, wherein grinding is performed in step one by adding grinding fluid under air condition, and 9-22 ml of grinding fluid is added into 10g of powder for 3-8 min; in the first step, the ball milling time is 3-6 h.

4. The method of claim 3, wherein the polishing slurry is methanol, ethanol, ethylene glycol or deionized water.

5. The method for preparing the M-site vanadium-doped MXene according to claim 1, wherein in the first step, the sintering temperature is 960-1430 ℃ for 3-6h, the sintering atmosphere is inert gas or a mixture of inert gas and any one of oxygen, hydrogen and carbon dioxide in any proportion, and the inert gas is argon.

6. The method for preparing the M-site vanadium-doped MXene according to claim 1, wherein the mixed molten salt is subjected to mixed recrystallization before use, specifically: and dissolving the weighed mixed molten salt in water, heating to evaporate water to obtain crystalline salt, and finally grinding and refining to obtain the finally used mixed molten salt.

7. The method for preparing the MXene doped with vanadium at the M position according to claim 1, wherein the carbon powder is any one of graphite powder, conductive carbon black, carbon fiber and activated carbon.

8. The method for preparing the M-site doped vanadium MXene according to claim 1, wherein the etchant is hydrofluoric acid, a lithium fluoride hydrochloride solution or a sodium fluoride hydrochloride solution; when a lithium fluoride hydrochloride solution is used, 1g of lithium fluoride is contained in each 30ml of the lithium fluoride hydrochloride solution; when a sodium fluoride hydrochloride solution is used, 1g of sodium fluoride is contained per 30ml of the sodium fluoride hydrochloride solution.

9. The method for preparing M-bit doped vanadium MXene according to claim 1, wherein the ratio of MAX phase powder to etchant in the second step is: 30-35 ml of etching agent is matched with 5-10 g of MAX phase powder.

Technical Field

The invention relates to a preparation method of a two-dimensional layered material, in particular to a preparation method of M-site ternary doped vanadium MXene.

Background

A series of two-dimensional nano materials (collectively called MXene materials) with similar structures can be prepared based on the selective corrosion of A layer atoms in MAX phase powder and the combination of liquid phase stripping. The material has various electrical, magnetic and thermoelectric properties and excellent characteristics of electrochemistry, heavy metal ion adsorption, gas adsorption and the like, and has very wide application prospect in the fields of ion batteries, super capacitors, sewage treatment, hydrogen storage and the like. Therefore, the preparation of MXene materials by the corrosion exfoliation of MAX phase powders has become one of the hot spots in the two-dimensional nanomaterial research field in recent years.

V₂CT_xIs a typical MXene material, has received wide attention in recent years, and a plurality of expert scholars obtain V through theoretical calculation₂CT_xThe largest theoretical cell capacity in MXene materials, but the stronger V-Al bond limits the delamination of the Al layer from the MAX phase, making it difficult to obtain V of high purity₂CT_x(ii) a On the other hand, the similarity of MXene structure and the diversity of composition are considered, as well as the metal V oxide VO₂Excellent electrochemical performance, and can enrich V if other metal elements can be properly doped in the V layer to realize solid solution and slightly oxidize in the process₂CT_xThe composition, the construction of complex charge centers, and the regulation of their performance. Thus to V₂CT_xThe solution doping is carried out to further promote V₂CT_xThe electrochemical performance is critical.

Chinese patent with application number CN201910847191.8, MXene material and its preparation method and application, MAX phase material, transition metal bromide and/or transition metal iodide are mixed and reacted at high temperature to obtain MXene material with Br or I as surface group, which has unique electrochemical performance, but does not realize doping of V layer and has limited performance regulation and control on material; chinese patent CN201510164821.3 in the Specification of "A porous two-dimensional transition Metal carbide and its preparation method" (V)_1-xCr_x)₂The preparation process of AlC ceramic powder and the (V) obtained by liquid phase etching_1-xCr_x)₂CT_xTwo-phase solid solution of V-doped Cr is realized, but it is obvious that it cannot realize the same in V-phaseDoping two elements to prepare M-site doped V₂CT_x。

Disclosure of Invention

The invention aims to provide a preparation method of M-bit ternary doped vanadium MXene to overcome the defects in the prior art₂CT_xMXene is prepared by regulating raw material proportion, refining pretreatment process to oxidize raw material in trace amount, special atmosphere one-step molten salt method and liquid phase stripping process₂CT_xMeanwhile, the surface oxidation is realized, so that the electrochemical performance of the material is improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of M-bit vanadium-doped MXene comprises the following steps:

the method comprises the following steps: mixing metal powder, aluminum powder, carbon powder and mixed molten salt to prepare powder; grinding the powder to preliminarily mix the powder, then carrying out ball milling to obtain powder, and then sintering the powder in high-temperature atmosphere to obtain M-bit doped MAX phase powder which is recorded as MAX phase powder; the metal powder is three-phase mixed powder formed by V powder and any two of Ti powder, Cr powder, Mo powder, Zr powder and Nb powder, and the molar ratio of the V powder in the three-phase mixed powder is more than 50 percent; the mixed molten salt is a mixture of sodium chloride and potassium chloride in any proportion;

step two: mixing MAX phase powder and etchant, stirring at 20-35 deg.C for 12-36h, cleaning, centrifuging, and oven drying to obtain M-site doped V₂CT_xMXene。

Further, the molar ratio of the metal powder, the aluminum powder, the carbon powder and the mixed molten salt in the step one is (2-2.3): (1.05-1.2): (1-1.1): (5-25).

Further, grinding is carried out under the air condition after grinding fluid is added in the step one, and 9-22 ml of grinding fluid is added into every 10g of powder, wherein the grinding time is 3-8 min; in the first step, the ball milling time is 3-6 h.

Further, the grinding fluid is methanol, ethanol, ethylene glycol or deionized water.

Further, in the first step, the sintering temperature is 960-1430 ℃ for 3-6h in a high-temperature atmosphere, the sintering atmosphere is inert gas or mixed gas of the inert gas and any one of oxygen, hydrogen and carbon dioxide in any proportion, and the inert gas is argon.

Further, the mixed molten salt is subjected to mixed recrystallization before use, specifically: and dissolving the weighed mixed molten salt in water, heating to evaporate water to obtain crystalline salt, and finally grinding and refining to obtain the finally used mixed molten salt.

Further, the carbon powder is any one of graphite powder, conductive carbon black, carbon fiber and activated carbon.

Further, the etching agent is hydrofluoric acid, a lithium fluoride hydrochloride solution or a sodium fluoride hydrochloride solution; when a lithium fluoride hydrochloride solution is used, 1g of lithium fluoride is contained in each 30ml of the lithium fluoride hydrochloride solution; when a sodium fluoride hydrochloride solution is used, 1g of sodium fluoride is contained per 30ml of the sodium fluoride hydrochloride solution.

Further, in the second step, the ratio of the MAX phase powder to the etching agent is as follows: 30-35 ml of etching agent is matched with 5-10 g of MAX phase powder.

Compared with the prior art, the invention has the following beneficial technical effects:

the invention controls the proportion of raw materials, refines the pretreatment process, oxidizes the raw materials in a trace manner, and combines a one-step molten salt method and a liquid phase stripping process to prepare the M-site doped V₂CT_xMXene, V regulated by M-site doping₂CT_xThe MXene structure can construct a complex charge center, weaken the action of a V-Al bond and improve V₂Liquid phase stripping capability of Al layer in AlC; grinding in air, combining with special sintering atmosphere to oxidize the raw material in trace amount to obtain V₂CT_xThe MXene surface contains a small amount of oxide, so that the electrochemical performance is promoted to be improved; the method adopts a one-step molten salt method to realize M-site multi-element doping, and has the advantages of simple process, controllable process, high product purity, good crystallization morphology and the like.

Drawings

FIG. 1 shows the double-element doped V with Ti and Cr at M position obtained in example 1₂CT_xMxene photo, wherein a is M-site Ti and Cr double-element doped V₂CT_xSEM photograph of MXene, b is M-site Ti and Cr doped double-element V₂CT_xPhotos of the Tdahl phenomenon of MXene.

Detailed Description

Embodiments of the invention are described in further detail below:

a preparation method of M-bit vanadium-doped MXene comprises the following steps:

the method comprises the following steps: mixing metal powder, aluminum powder, carbon powder and molten salt according to a certain ratio to prepare powder, wherein the mixing ratio of the metal powder, the aluminum powder, the carbon powder and the molten salt is (2-2.3): (1.05-1.2): (1-1.1): (5-25), wherein the metal powder is a tri-mixed powder formed by V powder and any two of Ti, Cr, Mo, Zr and Nb powder, the molar ratio of the V powder in the tri-mixed powder is required to be more than 50%, the mixed molten salt is a mixture of sodium chloride and potassium chloride in any ratio, the mixed molten salt needs to be mixed and recrystallized before use, namely the weighed mixed molten salt is dissolved in a small amount of water, then the water is heated and evaporated to dryness to obtain crystallized salt, and finally the crystallized salt is ground and refined to obtain finally usable mixed molten salt, and the carbon powder is any one of graphite powder, conductive carbon black, carbon fiber, active carbon and the like; then placing the powder into a mortar, weighing 10g of mixed powder, adding 9-22 ml of grinding liquid (methanol, ethanol, ethylene glycol, deionized water and other solutions), grinding for 3-8min under the air condition to preliminarily mix the powder, then transferring the powder into a ball milling tank for ball milling for 3-6h to obtain powder, and then placing the powder into a magnetic boat for high-temperature atmosphere sintering, wherein the high-temperature atmosphere sintering process comprises the following steps: at 960-1430 ℃, the sintering atmosphere is inert atmosphere argon or a mixture of argon and any one of oxygen, hydrogen and carbon dioxide in any proportion, the sintering heat preservation time is 3-6h, M-position doped MAX phase is obtained and is recorded as MAX phase powder;

step two: mixing MAX phase powder and an etching agent according to a certain proportion, wherein the proportion of MAX phase powder to the etching agent is that 30-35 ml of the etching agent is matched with 1 every 5-10 g of MAX phase powder, and etchingThe preparation is hydrofluoric acid, lithium fluoride hydrochloride solution (each 30ml contains 1g of lithium fluoride) or sodium fluoride hydrochloride solution (each 30ml contains 1g of sodium fluoride), then the mixture is magnetically stirred for 12 to 36 hours at the temperature of 20 to 35 ℃, and after the magnetic stirring, the mixture is cleaned, centrifugally separated and dried to obtain M-doped V₂CT_xMXene。

The following describes a specific technical solution of the present invention with reference to examples. The following examples are merely illustrative of the reliable and effective implementation of the technical solutions of the present invention, but the technical solutions of the present invention are not limited to the following examples.