A method for constructing strain-type MXene / vanadium selenide applied to capacitive deionization

Abstract

The application relates to a construction method of strain type MXene / vanadium selenide applied to capacitive deionization. The purpose of the application is to solve the problems of easy stacking of MXene and fewer active sites, and provide a construction method of strain type MXene / vanadium selenide with high adsorption performance. Method: V2AlC, hydrofluoric acid and selenium powder are used as raw materials, and an etching method, a calcination method and a liquid nitrogen quenching method are adopted to obtain strain type MXene / vanadium selenide with high adsorption performance, so as to provide a construction method for improving the capacitive deionization performance of the existing MXene-based materials.

Description

TECHNICAL FIELD

[0001] The application relates to a construction method of a strain type MXene / vanadium selenide applied to capacitive deionization. BACKGROUND

[0002] As a new desalination method, the capacitive deionization technology can store ions in electrode materials by applying a voltage between two electrodes under normal temperature and pressure, and can realize electrode regeneration by applying a reverse voltage or short circuiting. The capacitive deionization technology has the characteristics of high desalination efficiency, low energy consumption and environmental friendliness. The capacitive deionization technology of seawater and brackish water is considered to be a promising solution to the shortage of fresh water resources. At present, one of the research focuses of the technology is to develop efficient and stable electrode materials.

[0003] The MXene material is concerned due to high conductivity, high capacity and good hydrophilicity, but the problems of easy stacking and few active sites need to be improved. Therefore, the MXene-based electrode material is reasonably modified, the heterostructure is constructed by in-situ partial selenization, the stacking of the MXene is overcome, the rich electrochemical active sites are provided by changing the interplanar spacing through liquid nitrogen quenching, so that the electrochemical performance is improved, and the MXene is used as a good capacitive deionization electrode material. It has important research significance for designing excellent performance capacitive deionization electrode materials. SUMMARY

[0004] The application aims to overcome the problems of easy stacking and few active sites of the MXene, and provide a simple, novel and high-yield construction method.

[0005] The construction method of the strain type MXene / vanadium selenide applied to capacitive deionization is completed according to the following steps:

[0006] (1) V2AlC powder is etched by using hydrofluoric acid with a mass concentration of 40% under the conditions of water bath heating and stirring, after etching, the dispersion liquid is centrifuged, and deionized water is repeatedly washed until the pH is 6, and then dried;

[0007] (2) The product in step (1) and selenium powder are put into a ball mill jar, and ball milling is performed;

[0008] (3) 0.2 grams of the mixture in step (2) is placed in a tube furnace and calcined under N2 protection, and then quenched by liquid nitrogen to obtain a strain type MXene / vanadium selenide material;

[0009] The volume of hydrofluoric acid in step (1) is 20-30 milliliters, the water bath heating temperature is 30-60 degrees Celsius, the stirring time is 90-150 hours, and the drying condition is vacuum drying at 60-80 degrees Celsius for 10-15 hours.

[0010] The mass ratio of the product in step (1) to selenium powder in step (2) is 1:1.5-1:3, the ball milling speed is 500-800 revolutions per minute, and the ball milling time is 10-30 minutes.

[0011] The calcination temperature in step (3) is 500-800 degrees Celsius, the calcination time is 2-3 hours, and the liquid nitrogen quenching temperature is 25-600 degrees Celsius.

[0012] Compared with the prior art, the application has the beneficial effects that: the application constructs a strain type MXene / vanadium selenide applied to capacitive deionization, in the construction process, a heterostructure is constructed and lattice strain is realized by a novel method, a strain type MXene / vanadium selenide material is prepared, and the material has excellent capacitive deionization performance. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a scanning electron microscope graph of the strain type MXene / vanadium selenide of Example 1.

[0014] Figure 2 It is a powder X-ray diffraction spectrum graph of the strain type MXene / vanadium selenide of Example 1 and a control group thereof.

[0015] Figure 3 It is an electrochemical performance graph of the strain type MXene / vanadium selenide of Example 1 and a control group thereof.

[0016] Figure 4 It is a desalination capacity and average desalination rate performance graph of the strain type MXene / vanadium selenide of Example 1. DETAILED DESCRIPTION

[0017] The technical scheme of the application is not limited to the following specific embodiments, and the following specific embodiments are only used to illustrate the application and are not limited to the technical scheme described in the examples of the application. Those skilled in the art should understand that the application can still be modified or replaced equivalently to achieve the same technical effect. As long as the use needs are met, it is within the protection scope of the application.

[0018] The construction method of the strain type MXene / vanadium selenide applied to capacitive deionization of the embodiment is completed according to the following steps:

[0019] (1) V2AlC powder is etched by using 40% mass concentration of hydrofluoric acid with a volume of 20 milliliters under heating and stirring in a 35-degree Celsius water bath for 120 hours, after etching is completed, the dispersion liquid is centrifuged, and repeatedly washed with deionized water until the pH is 6, and the precipitate is vacuum dried at 80 degrees Celsius for 12 hours;

[0020] (2) 0.2 grams of the product in step (1) and 0.4 grams of selenium powder are put into a ball mill jar, and ball milling is performed for 10 minutes;

[0021] (3) 0.2 grams of the mixture in step (2) are placed in a porcelain boat of a tube furnace, and calcination is performed at 550 degrees Celsius for 2 hours under N2 protection, and then liquid nitrogen quenching is performed when it is cooled to 250 degrees Celsius, to obtain a strain type MXene / vanadium selenide material;

[0022] The application will be further described below in combination with the drawings and examples:

[0023] Figure 1 It is a scanning electron microscope image of the strain type MXene / vanadium selenide of Example 1. The MXene is in a kind of accordion-like structure, which is synergistically regulated by heterostructure and lattice strain, forms a heterostructure after in-situ selenization in the calcination process, and then lattice tensile strain occurs through liquid nitrogen quenching.

[0024] Figure 2 It is a powder X-ray diffraction spectrum of the strain type MXene / vanadium selenide of Example 1 and its control group. Compared with vanadium carbide / vanadium selenide without liquid nitrogen quenching, the powder X-ray diffraction characteristic peak of the sample after liquid nitrogen quenching at 100, 250, 400 and 550 degrees Celsius is offset to a small angle due to the strong external force.

[0025] Figure 3 It is an electrochemical performance diagram of the strain type MXene / vanadium selenide of Example 1 and its control group. In a 1 mol L -1 of aqueous sodium chloride solution, under a voltage range of-0.8~0.2V, the samples at different quenching temperatures show different adsorption properties.

[0026] Figure 4 It is a desalination capacity and average desalination rate performance diagram of the strain type MXene / vanadium selenide of Example 1. The electrode material is at a voltage of 1.2V, and the sodium chloride concentration is 100, 300, 500, 1000 and 2000 milligrams per liter, respectively, and the desalination capacity and desalination rate performance diagram.

Claims

1. A method for constructing a strain MXene / vanadium selenide applied to capacitive deionization, the method being completed according to the following steps: (1) etching V2AlC powder with hydrofluoric acid with a mass concentration of 40% under the conditions of water bath heating and stirring, after etching, centrifuging the dispersion liquid, repeatedly washing with deionized water until the pH is 6, and drying; (2) putting the product in step (1) and selenium powder into a ball milling tank and performing ball milling; (3) placing 0.2 g of the mixture in step (2) in a tube furnace, calcining under the condition of nitrogen protection, and then quenching by liquid nitrogen to obtain a strain MXene / vanadium selenide material.

2. The method according to claim 1, wherein the method is characterized by: In step (1), the volume of hydrofluoric acid is 20-30 ml, the water bath heating temperature is 30-60 DEG C, the stirring time is 90-150 hours, and the drying condition is vacuum drying at 60-80 DEG C for 10-15 hours.

3. The method of claim 1, wherein the method is applied to a strain MXene / vanadium selenide. In step (2), the mass ratio of the product in step (1) to selenium powder is 1:1.5-1:3, the ball milling speed is 500-800 rpm per minute, and the ball milling time is 10-30 minutes.

4. The method of claim 1, wherein the method is a method of constructing a strain MXene / vanadium selenide for capacitive deionization. In step (3), the calcination temperature is 500-800 DEG C, the calcination time is 2-3 hours, and the liquid nitrogen quenching temperature is 25-600 DEG C.

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