阅读说明：本技术 一种电化学法制备黑磷纳米片的装置及方法 (Device and method for preparing black phosphorus nanosheet by electrochemical method ) 是由 刘畅 王佳宏 汪建南 刘丹妮 喻学锋 于 2021-09-25 设计创作，主要内容包括：本发明公开了一种电化学高效制备黑磷纳米片的装置,其包括恒流电源、电解槽、电解液、惰性电极、固定支架、压力装置(砝码)、黑磷及绝缘过滤层。本发明还公开了该装置的使用方法,以块状黑磷作为工作电极,以惰性材料作为对电极,与有机系电解液共同构建电化学反应体系。相比较于传统的电化学剥离装置,本装置可直接对大块黑磷晶体进行剥离,无需进行破碎处理,单次处理量显著提升。此外,相比较于传统的电极夹子固定方式,压力装置的接触面积更大,且受到压力装置自身重力作用,剥离过程中黑磷始终与电极保持接触,剥离效率更高,可有效解决传统方法剥离不彻底的问题。且一体化的过滤装置,更有利于剥离产物的收集。(The invention discloses a device for electrochemically and efficiently preparing black phosphorus nanosheets, which comprises a constant current power supply, an electrolytic cell, electrolyte, an inert electrode, a fixed support, a pressure device (weight), black phosphorus and an insulating filter layer. The invention also discloses a using method of the device, which takes the blocky black phosphorus as a working electrode, takes an inert material as a counter electrode and constructs an electrochemical reaction system together with the organic electrolyte. Compare in traditional electrochemistry stripping off device, this device can directly peel off the bold black phosphorus crystal, need not to carry out broken handle, and single treatment capacity is showing and is promoting. In addition, compare in traditional electrode clip fixed mode, pressure device's area of contact is bigger, and receives pressure device self action of gravity, and the black phosphorus keeps contact with the electrode all the time among the peeling process, and peeling efficiency is higher, can effectively solve traditional method and peel incomplete problem. And the integrated filtering device is more beneficial to the collection of stripping products.)

1. The device for preparing the black phosphorus nanosheets by the electrochemical method comprises a constant current power supply (1), an electrolytic cell (2), inert electrodes (4), fixed supports (5), a pressure device (6), black phosphorus (7) and an insulating filter layer (8), and is characterized in that the two fixed supports (5) are arranged in the electrolytic cell (2), the insulating filter layer (8) is arranged on the fixed supports (5), the inert electrodes (4) are arranged in the inner side of the fixed supports (5) and the outer side of the fixed supports (5) in a hanging mode, and the inert electrodes (4) and the insulating filter layer (8) on the inner side of the fixed supports (5) are used for placing the black phosphorus.

2. The device for preparing black phosphorus nanosheets by the electrochemical method according to claim 1, wherein a constant current power supply (1) and the inert electrode (4) are connected and assembled by a lead.

3. The apparatus for electrochemically preparing black phosphorus nanosheets according to claim 1, wherein a pressure device (6) is disposed above the inert electrode (4) inside the fixed support (5).

4. The device for preparing black phosphorus nanosheets by the electrochemical method according to claim 3, wherein the pressure device (6) is an alloy formed by any one or a combination of aluminum, zinc, iron, tin, copper, silver and nickel.

5. A method for preparing black phosphorus nanosheets by an electrochemical method is characterized by comprising the following steps: use of the device of any one of claims 1-4 for the preparation of black phosphorus nanoplates by the following steps:

(1) weighing an intercalating agent in an organic solvent, and taking the intercalating agent as an electrolyte for standby after the intercalating agent is fully dissolved;

(2) adding electrolyte into the device of any one of claims 1-4, arranging black phosphorus between the inert electrode and the insulating filter layer, compacting, using the black phosphorus as a working electrode, using the other inert electrode as a counter electrode, connecting all the electrodes with a constant current power supply through leads, and immersing the electrodes in the electrolyte to jointly construct an electrochemical reaction system;

(3) and continuously electrifying for a period of time, carrying out intercalation reaction on ions in the electrolyte, and obtaining an expansion body which is the black phosphorus nanosheet after complete stripping.

6. A method of electrochemically preparing black phosphorus nanoplates as in claim 5, wherein: the intercalating agent in the step (1) is any one or a combination of a plurality of alkyl halogenated quaternary ammonium salts or multi-halogenated quaternary ammonium salts of C1-C10, and the concentration of the intercalating agent is 0.1-10 mol/L.

7. A method of electrochemically preparing black phosphorus nanoplates as in claim 5, wherein: the organic solvent in the step (1) comprises any one of N-methylpyrrolidone, dimethyl sulfoxide, 1, 3-dimethyl imidazolidin-2-one, dimethylacetamide and diethylformamide.

8. A method of electrochemically preparing black phosphorus nanoplates as in claim 5, wherein: the insulating filter layer is made of any one or a combination of more of fluorine resin, chlorinated polyether, PPS, PVC, PE, PP and PB, and the size of the filter holes is 0.1-1 mm.

9. A method of electrochemically preparing black phosphorus nanoplates as in claim 5, wherein: the mass ratio of the pressure device to the black phosphorus crystal in the step (2) is 2-5: 1, wherein the black phosphorus is a large black phosphorus crystal, is not crushed and has a mass of 0.1-100 g; the inert electrode is any one of platinum, carbon, gold and titanium.

10. A method of electrochemically preparing black phosphorus nanoplates as in claim 5, wherein: the electrifying reaction condition in the step (3) is that the black phosphorus is subjected to intercalation treatment by adopting 10-100 mA constant current at the temperature of 20-60 ℃, and the treatment time is 0.1-12 h.

Technical Field

The invention belongs to the technical field of two-dimensional materials, and particularly relates to a device and a method for electrochemically and efficiently preparing black phosphorus nanosheets.

Background

Graphene has been well known to be popular with researchers due to its unique physicochemical properties. In recent years, black phosphorus has gradually become a secondary grapheneAnd then a new two-dimensional material which is excited by the semiconductor technology and industrial application. Black phosphorus possesses extremely high carrier mobility (1000 cm)²V^-1s^-1) And a good on-off ratio (10)⁵) And a direct band gap (0.3-1.5 eV) tunable with the layer number variation. The characteristics make up the performance defects of zero band gap of graphene, low carrier mobility of transition metal chalcogenide (TMDS) and the like, so that the black phosphorus has great potential in the application aspect of novel optoelectronic devices.

At present, the research and application of black phosphorus face a great challenge, namely how to efficiently prepare high-quality black phosphorus nanosheets in a large batch at low cost. The chemical stripping method and the liquid phase stripping method are mainly widely applied at present. For example, patent CN109019540A discloses a method for preparing black phosphorus nanosheets. Black phosphorus is used as an electrode, an organic solvent containing an intercalation agent is used as an electrolyte, current or voltage is applied between the electrodes to carry out intercalation and expansion on the black phosphorus, centrifugation is carried out after filtration, washing and ultrasonic oscillation treatment, and supernatant is collected to obtain the black phosphorus nanosheet dispersion liquid with uniform size. For another example, patent CN108394879A discloses a black phosphorus alkene and a preparation method thereof. Grinding black phosphorus, placing the ground black phosphorus in an N-methyl pyrrolidone solvent, placing the ground black phosphorus in an ultrasonic cell crusher for crushing under the ice bath condition, centrifuging the obtained solution, and taking supernatant to obtain the black phosphorus diluent.

The former strips black phosphorus to prepare nanosheets by expanding black phosphorus through electrochemical ion intercalation, although the yield is high, the obtained black phosphorus nanosheets are few in layer and good in quality, the black phosphorus nanosheets are limited by a stripping device, the single-time stripping amount is very limited, the phenomenon of incomplete stripping is easy to occur, and the product collection is also complex. The latter method utilizes ultrasonic means to strip the black phosphorus dispersed in the liquid phase, although the single treatment capacity is improved, the stripping effect is limited by the energy and ultrasonic time of ultrasonic wave, the overall yield is low, the stripping time is long, and the two methods are difficult to realize continuous mass production. Therefore, a device and a method for efficiently preparing high-quality black phosphorus nanosheets at low cost in large batch are developed to solve the problems that the existing black phosphorus preparation device is not thorough in stripping, low in yield and difficult to amplify and the like, and have important values in widening industrial-level applications of black phosphorus materials in various fields such as photoelectric devices, energy catalysis and biomedical treatment.

Disclosure of Invention

According to the invention, the black phosphorus nanosheet is efficiently prepared based on electrochemical ion intercalation by using an autonomously designed stripping device, using massive black phosphorus as a working electrode, using an inert material as a counter electrode and constructing an electrochemical reaction system together with an organic electrolyte. Compared with the traditional electrochemical stripping device, the device can directly strip the large black phosphorus crystal without carrying out crushing treatment, the single treatment capacity is obviously improved, and the high-quality black phosphorus nanosheet can be easily prepared at low cost and in large batch with high efficiency. In addition, compare in traditional electrode clip fixed mode, pressure device's area of contact is bigger, and it is higher to peel off efficiency, can effectively solve traditional method and peel off not thorough, the productivity is not high, be difficult to enlarge scheduling problem. And the integrated filtering device is more beneficial to the collection of stripping products. Has important value for widening industrial application of the black phosphorus material in various fields of photoelectric devices, energy catalysis, biological medical treatment and the like.

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

the device comprises a constant-current power supply, an electrolytic bath, inert electrodes, fixed supports, a pressure device, black phosphorus and an insulating filter layer, wherein two fixed supports are arranged in the electrolytic bath, the insulating filter layer is arranged on the fixed supports, the inert electrodes are arranged in the fixed supports and outside the fixed supports in a hanging mode, and the inert electrodes and the insulating filter layer on the inner sides of the fixed supports are used for placing black scales. A schematic of the apparatus is shown in figure 1.

The constant current power supply and the inert electrode are connected and assembled by a lead.

A pressure device is arranged above the inert electrode on the inner side of the fixed support.

The pressure device is an alloy formed by any one or combination of more of aluminum, zinc, iron, tin, copper, silver and nickel.

The method for electrochemically and efficiently preparing the black phosphorus nanosheet adopts the device for preparing the black phosphorus nanosheet, and comprises the following steps:

(1) weighing an intercalating agent in an organic solvent, and taking the intercalating agent as an electrolyte for standby after the intercalating agent is fully dissolved;

(2) adding electrolyte into the device, arranging black phosphorus between the inert electrode and the insulating filter layer, compacting, taking the black phosphorus as a working electrode, taking the other inert electrode as a counter electrode, connecting all the electrodes with a constant current power supply through leads, and immersing the electrodes into the electrolyte to jointly construct an electrochemical reaction system;

(3) and continuously electrifying for a period of time, carrying out intercalation reaction on ions in the electrolyte, and obtaining an expansion body which is the black phosphorus nanosheet after complete stripping.

(4) And dispersing the completely stripped expansion body in the electrolyte through a filter layer, collecting the expansion body, cleaning for several times, and then carrying out ultrasonic treatment and centrifugation to finally obtain the high-quality black phosphorus nanosheet.

The intercalating agent in the step (1) is any one or a combination of a plurality of alkyl halogenated quaternary ammonium salts or multi-halogenated quaternary ammonium salts of C1-C10, and the concentration of the intercalating agent is 0.1-10 mol/L.

The organic solvent in the step (1) comprises any one of N-methylpyrrolidone, dimethyl sulfoxide, 1, 3-dimethyl imidazolidin-2-one, dimethylacetamide and diethylformamide.

The material of the pressure device (weight) in the step (2) is any one or combination of more of aluminum, zinc, iron, tin, copper, silver and nickel, the mass is 0.2-500 g, and the mass ratio of the pressure device (weight) to the black phosphorus crystal is 2-5: 1.

preferably, the pressure device (weight) is made of any one or a combination of several of iron, tin, copper and nickel, the mass of the pressure device (weight) is 50-250 g, and the mass ratio of the pressure device (weight) to the black phosphorus crystal is 4-5: 1.

the black phosphorus is a large black phosphorus crystal, is not crushed and has the mass of 0.1-100 g; preferably, the mass of the black phosphorus is 10-50 g.

The insulating filter layer is made of corrosion-resistant polymer materials, is made of any one or a combination of more of fluorine resin, chlorinated polyether, PPS, PVC, PE, PP and PB, and has a filter hole size of 0.1-1 mm.

Preferably, the insulating filter layer is made of a corrosion-resistant polymer material, and is made of any one or a combination of several of fluorine resin, chlorinated polyether and PPS, and the size of the filter holes is 0.2-0.5 mm.

The inert electrode is any one of platinum, carbon, gold and titanium. Preferably, the inert electrode is any one of platinum and carbon.

The electrifying reaction condition in the step (3) is that the black phosphorus is subjected to intercalation treatment by adopting 10-100 mA constant current at the temperature of 20-60 ℃, and the treatment time is 0.1-12 h.

Preferably, the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting constant current of 30-50 mA at the temperature of 25-40 ℃, and the treatment time is 0.5-6 h.

The power of the ultrasonic treatment in the step (4) is 100-2000W, and the time is 0.1-12 h; the rotation speed of the centrifugal treatment is 1000-7000 r/min, and the time is 1-30 min.

Preferably, the power of the ultrasonic treatment is 500-1000W, and the time is 0.5-6 h; the rotation speed of the centrifugal treatment is 3000-.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, the black phosphorus nanosheet is efficiently prepared based on electrochemical ion intercalation by using an autonomously designed stripping device, using massive black phosphorus as a working electrode, using an inert material as a counter electrode and constructing an electrochemical reaction system together with an organic electrolyte. Compared with the traditional electrochemical stripping device, the single treatment capacity is only 0.01-1 g, and the massive black phosphorus crystal needs to be crushed. The device can directly strip the large black phosphorus crystal without crushing treatment, the single treatment capacity can reach 10-100 g, the improvement is remarkable, and the low-cost large-batch high-efficiency preparation of the high-quality black phosphorus nanosheet is more facilitated.

(2) In the invention, the black phosphorus is fixed by applying external pressure to the black phosphorus by using a pressure device (weight) in the self-designed stripping device, and the pressure can be regulated and controlled by controlling the weight of the weight. Compare in traditional electrode clip fixed mode, in the stripping process, the black phosphorus inflation body that obtains can be attached to the surface of bold black phosphorus crystal usually, and on the one hand it has hindered the contact of inside black phosphorus with electrolyte, has reduced intercalation reaction efficiency. On the other hand, it also hinders efficient contact between the black phosphorus crystal and the electrode, further affecting the degree of exfoliation. The pressure device (weight) used in the invention can press the stripped expansion body due to the self gravity effect, and accelerate the completely stripped black phosphorus to pass through the filter layer. On the other hand, the contact area of the pressure device is larger, the incompletely stripped black phosphorus is always in contact with the electrode under the action of pressure, the stripping efficiency is higher, and the problems that the traditional method is incomplete in stripping, low in yield, difficult to amplify and the like can be effectively solved.

(3) In the invention, the integrated filtering device in the stripping device which is designed independently is utilized, so that the collection of stripping products is facilitated. The completely stripped black phosphorus is dispersed in the electrolyte through the filter layer, the incompletely stripped black phosphorus stays on the filter layer, and secondary stripping is carried out under the action of the pressure device until the completely stripped black phosphorus passes through the filter layer.

(4) The device of the invention has simple and easily obtained related elements, is easy to assemble and is suitable for batch production and assembly. The method has the advantages of simple and easily obtained raw materials, mild synthesis conditions, easy regulation and control, simple operation process, convenient repetition and large-scale synthesis.

Drawings

FIG. 1 is a schematic view of an electrochemical peeling apparatus in example 1;

in the figure, 1, a constant current power supply, 2, an electrolytic cell, 3, electrolyte, 4, an inert electrode, 5, a fixed support, 6, a pressure device (weight), 7, black phosphorus, 8 and an insulating filter layer.

Fig. 2 is an X-ray diffraction spectrum of the black phosphorus nanosheet obtained in example 3.

Fig. 3 is a scanning electron microscope image of the black phosphorus nanosheet obtained in example 3.

Fig. 4 is an atomic force microscope image of the black phosphorus nanoplatelets obtained in example 3, wherein a is a high resolution microscope image and B is a graphical representation of the black phosphorus thickness.

FIG. 5 is a diagram showing the peeling process of the black phosphorus crystal in example 3, in which diagram A is a diagram showing the real object at the time of peeling 10 min, diagram B is a diagram showing the real object at the time of peeling 20 min, diagram C is a diagram showing the real object at the time of peeling 30 min, and diagram D is a diagram showing the real object of the product after the peeling is finished.

Fig. 6 is a scanning electron micrograph of the black phosphorus nanoplates obtained in example 4.

Fig. 7 is an X-ray diffraction spectrum of the black phosphorus nanosheet obtained in comparative example 1.

Fig. 8 is a scanning electron micrograph of the black phosphorus nanosheet obtained in comparative example 1.

Fig. 9 is an atomic force microscope image of the black phosphorus nanosheet obtained in comparative example 1, wherein image a is a high resolution microscope image and image B is a graphical representation of the black phosphorus thickness.

FIG. 10 is a drawing showing a peeling process of a black phosphorus crystal in comparative example 1, in which A is a drawing showing an actual object at the time of peeling at 1 min, B is a drawing showing an actual object at the time of peeling at 10 min, C is a drawing showing an actual object at the time of peeling at 20 min, and D is a drawing showing an actual object at the time of peeling at 30 min.

Detailed Description

For a better understanding of the present invention, the following further illustrates the present invention with reference to specific examples and drawings, but the present invention is not limited to the following examples. Wherein, comparative example 1 is a black phosphorus nanosheet prepared using a conventional electrochemical stripping apparatus and method, and is distinguished from the black phosphorus nanosheet prepared using the self-designed stripping apparatus and method of comparative example 2.

Example 1

The device for preparing the black phosphorus nanosheets by the electrochemical method comprises a constant current power supply 1, an electrolytic bath 2, inert electrodes 4, fixed supports 5, a pressure device 6, black phosphorus 7 and an insulating filter layer 8, wherein the two fixed supports 5 are arranged in the electrolytic bath 2, the insulating filter layer 8 is arranged on the fixed supports 5, the inert electrodes 4 are arranged in the fixed supports 5 and the fixed supports 5 in a hanging mode, and the inert electrodes 4 and the insulating filter layer 8 on the fixed supports 5 are used for placing the black phosphorus. The constant current power supply 1 and the inert electrode 4 are connected and assembled by a lead. A pressure device 6 is arranged above the inert electrode 4 inside the fixed bracket 5. The pressure device 6 is made of nickel. The insulating filter layer is chlorinated polyether, and the size of the filter holes is 0.1-0.5 mm.

FIG. 1 is a schematic view of an electrochemical peeling apparatus in example 1.

Example 2

A method for electrochemically efficiently preparing black phosphorus nanosheets, using the apparatus of example 1 for the preparation of black phosphorus nanosheets, comprises the following steps:

1) weighing an intercalation agent tetramethylammonium fluoride in an organic solvent 1, 3-dimethyl imidazolidine-2-ketone, wherein the concentration of the intercalation agent tetramethylammonium fluoride is 0.1 mol/L, and taking the intercalation agent tetramethylammonium fluoride as an electrolyte for later use after the intercalation agent tetramethylammonium fluoride is fully dissolved;

2) a pressure device (aluminum weight, 0.2 g), a platinum electrode, 0.1 g of black phosphorus and a polytetrafluoroethylene insulation filter layer with the filter hole size of 0.1 mm are sequentially assembled on a fixed support from top to bottom, the black phosphorus is used as a working electrode, and the other inert electrode is used as a counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) electrifying for a period of time, wherein the electrifying reaction condition is that under the temperature of 20 ℃, the black phosphorus is intercalated by adopting constant current of 10 mA, and the treatment time is 0.1 h. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) dispersing the completely peeled expansion body in electrolyte through a filter layer, collecting the expansion body, cleaning for several times, and then carrying out ultrasonic and centrifugal treatment, wherein the power of ultrasonic treatment is 100W, and the time is 0.1 h; the rotation speed of the centrifugal treatment is 1000 r/min, and the time is 1 min. And finally obtaining the black phosphorus nanosheet.

Example 3

A method for electrochemically efficiently preparing black phosphorus nanosheets, using the apparatus of example 1 for the preparation of black phosphorus nanosheets, comprises the following steps:

1) weighing an intercalation agent tetrabutyl ammonium chloride in an organic solvent N, N-Dimethylformamide (DMF), wherein the concentration of the intercalation agent tetrabutyl ammonium chloride is 1 mol/L, and the intercalation agent tetrabutyl ammonium chloride is used as an electrolyte for standby after being fully dissolved;

2) a pressure device (iron weight, 50 g), a platinum electrode, 10 g of black phosphorus and a chlorinated polyether insulation filter layer with a filter hole size of 0.2 mm are sequentially assembled on a fixed support from top to bottom, the black phosphorus is used as a working electrode, and the other inert electrode is used as a counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) and continuously electrifying for a period of time, wherein the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting constant current of 30 mA at the temperature of 25 ℃, and the treatment time is 0.5 h. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) dispersing the completely peeled expansion body in the electrolyte through a filter layer, collecting the expansion body, cleaning for several times, and then carrying out ultrasonic and centrifugal treatment, wherein the power of ultrasonic treatment is 500W, and the time is 0.5 h; the rotation speed of the centrifugal treatment is 3000 r/min, and the time is 5 min. Finally obtaining the high-quality black phosphorus nanosheet.

Fig. 2 is an X-ray diffraction spectrum of the black phosphorus nanosheet obtained in example 3. As can be seen from the figure, the sample presents a typical black phosphorus characteristic peak, and no other miscellaneous peak appears, which indicates that the prepared black phosphorus nanosheet crystal form keeps good and has higher purity. The three strong characteristic peaks respectively correspond to the (020), (040) and (060) crystal faces of the black phosphorus crystal. Fig. 3 is a scanning electron microscope image of the black phosphorus nanosheet obtained in example 3. The size range of the prepared black phosphorus nanosheet is 200 nm-2 microns. Fig. 4 is an atomic force microscope image of the black phosphorus nanoplates obtained in example 3. The size of the prepared black phosphorus nanosheet is about 200 nm, and the thickness of the prepared black phosphorus nanosheet is about 23 nm. FIG. 5 is a diagram showing a process of peeling off black phosphorus crystals in example 3. As can be seen from the figure, in the stripping process, the completely stripped black phosphorus is continuously dispersed in the electrolyte through the filter layer, and the complete stripping of 10 g of black phosphorus crystals is finally realized through the electrochemical stripping of 0.5 h, and the collected black phosphorus product is a fluffy expansion body.

Example 4

An apparatus and a method for electrochemically and efficiently preparing black phosphorus nanosheets are used for preparing the black phosphorus nanosheets by using the apparatus in example 1, and the steps are as follows:

1) weighing an intercalation agent tetrapentyl ammonium bromide in an organic solvent N-methylpyrrolidone (NMP), wherein the concentration of the intercalation agent tetrapentyl ammonium bromide is 2 mol/L, and the intercalation agent tetrapentyl ammonium bromide is used as an electrolyte for standby after the intercalation agent tetrapentyl ammonium bromide is fully dissolved;

2) a pressure device (copper weight, 100 g), a carbon electrode, 25 g of black phosphorus and a PPS (polyphenylene sulfide) insulating filter layer with a filter hole size of 0.4 mm are sequentially assembled on a fixed support from top to bottom, the black phosphorus is used as a working electrode, and the other inert electrode is used as a counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) and continuously electrifying for a period of time, wherein the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting constant current of 40 mA at the temperature of 30 ℃, and the treatment time is 2 hours. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) the completely stripped expansion body is dispersed in electrolyte through a filter layer, the expansion body is collected, ultrasonic treatment and centrifugal treatment are carried out after the expansion body is cleaned for a plurality of times, the power of the ultrasonic treatment is 800W, and the time is 2 h; the rotation speed of the centrifugal treatment is 4000 r/min, and the time is 8 min. Finally obtaining the high-quality black phosphorus nanosheet.

Fig. 6 is a scanning electron micrograph of the black phosphorus nanoplates obtained in example 4. The size range of the prepared black phosphorus nanosheet is 200 nm-2 microns.

Example 5

A method for electrochemically efficiently preparing black phosphorus nanosheets, using the apparatus of example 1 for the preparation of black phosphorus nanosheets, comprises the following steps:

1) weighing an intercalation agent tetraoctyl ammonium bromide in an organic solvent dimethyl sulfoxide (DMSO), wherein the concentration of the tetraoctyl ammonium bromide is 5 mol/L, and the tetraoctyl ammonium bromide is used as an electrolyte for standby after the tetraoctyl ammonium bromide is fully dissolved;

2) a pressure device (silver weight, 250 g), a carbon electrode, 50 g of black phosphorus and a PVC (polyvinyl chloride) insulating filter layer with a filter hole size of 0.5mm are sequentially assembled on a fixed support from top to bottom, the black phosphorus is used as a working electrode, and the other inert electrode is used as a counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) and continuously electrifying for a period of time, wherein the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting 50 mA constant current at the temperature of 40 ℃, and the treatment time is 6 hours. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) dispersing the completely peeled expansion body in electrolyte through a filter layer, collecting the expansion body, cleaning for several times, and then carrying out ultrasonic and centrifugal treatment, wherein the power of ultrasonic treatment is 1000W, and the time is 6 h; the rotation speed of the centrifugal treatment is 5000 r/min, and the time is 10 min. Finally obtaining the high-quality black phosphorus nanosheet.

Example 6

A method for electrochemically efficiently preparing black phosphorus nanosheets, using the apparatus of example 1 for the preparation of black phosphorus nanosheets, the steps of:

1) weighing an intercalation agent tetradecyl ammonium bromide in an organic solvent 1, 3-dimethyl imidazolidine-2-ketone (DMI), wherein the concentration of the intercalation agent tetradecyl ammonium bromide is 10 mol/L, and the intercalation agent tetradecyl ammonium bromide is used as an electrolyte for standby after the intercalation agent tetradecyl ammonium bromide is fully dissolved;

2) a pressure device (iron weight, 500 g), a gold electrode, 100 g of black phosphorus and a PP (polypropylene) insulating filter layer with the filter hole size of 1 mm are sequentially assembled on a fixed support from top to bottom, the black phosphorus is used as a working electrode, and the other inert electrode is used as a counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) and continuously electrifying for a period of time, wherein the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting 100 mA constant current at the temperature of 60 ℃, and the treatment time is 12 h. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) dispersing the completely peeled expansion body in electrolyte through a filter layer, collecting the expansion body, cleaning for several times, and then carrying out ultrasonic and centrifugal treatment, wherein the power of ultrasonic treatment is 2000W, and the time is 12 h; the rotation speed of the centrifugal treatment is 7000 r/min, and the time is 30 min. Finally obtaining the high-quality black phosphorus nanosheet.

Comparative example 1

A traditional electrochemical preparation method of black phosphorus nanosheets adopts a laboratory traditional electrochemical stripping device for preparing the black phosphorus nanosheets, and comprises the following steps:

1) weighing an intercalation agent tetrabutyl ammonium chloride in an organic solvent N, N-Dimethylformamide (DMF), wherein the concentration of the intercalation agent tetrabutyl ammonium chloride is 1 mol/L, and the intercalation agent tetrabutyl ammonium chloride is used as an electrolyte for standby after being fully dissolved;

2) 2 g of black phosphorus fixed to a platinum electrode was used as the working electrode and the other inert electrode was used as the counter electrode. All the electrodes are connected with a constant current power supply through leads and immersed in electrolyte to jointly construct an electrochemical reaction system;

3) and continuously electrifying for a period of time, wherein the electrifying reaction condition is that the black phosphorus is subjected to intercalation treatment by adopting constant current of 30 mA at the temperature of 25 ℃, and the treatment time is 0.5 h. Carrying out intercalation reaction on ions in the electrolyte to obtain an expansion body which is a black phosphorus nanosheet aggregated with each other;

4) collecting the expansion body, cleaning for several times, and then carrying out ultrasonic treatment and centrifugal treatment, wherein the power of ultrasonic treatment is 500W, and the time is 0.5 h; the rotation speed of the centrifugal treatment is 3000 r/min, and the time is 5 min. And finally obtaining the black phosphorus nanosheet.

Fig. 7 is an X-ray diffraction spectrum of the black phosphorus nanosheet obtained in comparative example 1. As can be seen from the figure, the sample presents a typical black phosphorus characteristic peak, and no other miscellaneous peak appears, which indicates that the prepared black phosphorus nanosheet crystal form keeps good and has higher purity. The three strong characteristic peaks respectively correspond to the (020), (040) and (060) crystal faces of the black phosphorus crystal. Fig. 8 is a scanning electron micrograph of the black phosphorus nanosheet obtained in comparative example 1. The size range of the prepared black phosphorus nanosheet is 200 nm-2 microns. Fig. 9 is an atomic force microscope image of the black phosphorus nanosheet obtained in comparative example 1. The size of the prepared black phosphorus nanosheet is about 300 nm, and the thickness is about 17 nm. Fig. 10 is a diagram showing a process of peeling off black phosphorus crystals in comparative example 1. As can be seen from the figure, in the stripping process, the outer layer of the bulk crystal continuously expands, and after 0.5 h of electrochemical stripping, only the outer layer part of the black phosphorus is completely stripped and falls into the electrolyte, while the inner black phosphorus crystal still remains intact.

The black phosphorus nanosheets obtained by the two stripping modes are characterized by XRD, SEM and AFM, and basically have no difference in crystal quality, size and thickness degree. That is to say, the electrochemical stripping apparatus and method provided by the present invention can obtain high quality black phosphorus nanosheets compared with the conventional electrochemical stripping apparatus and method, but in contrast, in example 3 and comparative example 1, under the same energization reaction conditions, the former adopts a stripping apparatus designed autonomously, and can achieve complete stripping of 10 g of black phosphorus crystals within 0.5 h, while the latter can achieve partial stripping of only 2 g of black phosphorus crystals within 0.5 h, and the former is more advantageous in terms of single throughput, stripping efficiency, and product collection.

Therefore, the device and the method for electrochemically and efficiently preparing the black phosphorus nanosheet can be used for directly stripping the large black phosphorus crystal without crushing, the single treatment capacity is remarkably improved, and the high-quality black phosphorus nanosheet can be easily prepared in a large scale at low cost. In addition, compare in traditional electrode clip fixed mode, pressure device's area of contact is bigger, and it is higher to peel off efficiency, can effectively solve traditional method and peel off not thorough, the productivity is not high, be difficult to enlarge scheduling problem. And the integrated filtering device is more beneficial to the collection of stripping products. Has important value for widening industrial application of the black phosphorus material in various fields of photoelectric devices, energy catalysis, biological medical treatment and the like.