Black phosphorus nanosheet, preparation method therefor, and application thereof
The present invention relates to a method of preparing a black phosphorus nanosheet and application, belonging to the technical field of functional material production. In the method, the black phosphorus sheet is used as the electrolytic anode, and an electrochemical reaction system is constructed together with an inert electrode and an alkaline aqueous electrolyte, wherein the alkaline aqueous electrolyte comprises an N-N dimethylformamide solution dissolved with epoxy resin. In alkaline aqueous electrolyte, the prepared black phosphorus nanosheet structure tends to be more stable, not easy to be damaged and the oxidation degree is reduced. Under alkaline conditions, it is conducive to improve the intercalation and stripping effect of black phosphorus material of anode and make the black phosphorus exfoliation more complete.
1. A method of preparing a black phosphorous nanosheet, the method comprising:
preparing an alkaline aqueous electrolyte by:
1) preparing 0.1˜2 mol/L of a sulfate solution A and 0.1˜2 mol/L of a sulfate solution B, adding an alkaline solution to the sulfate solution B to adjust the pH value of sulfate solution B to 8˜14, and mixing evenly to obtain an alkaline aqueous electrolyte C, and
2) preparing an N-N dimethylformamide solution in which an epoxy resin is dissolved;
performing an electrochemical reaction in a constant temperature environment of 0˜10° C., with a black phosphorus sheet as an anode, an inert electrode as a cathode, and the sulfate solution A as an electrolyte, and a surface current density of 200˜500 mA/dm 2 under a DC voltage of 2.5˜3.5V for 1˜3 h;
transferring the anode and the cathode to the alkaline aqueous electrolyte C, and adding the N-N dimethylformamide solution with dissolved epoxy resin to the alkaline aqueous electrolyte C; and
applying a voltage of 5˜10V between the anode and the cathode, wherein the distance between electrodes remains unchanged, the area current density is controlled at 600˜900 mA/dm 2 , and precipitating black phosphorus for the black phosphorous nanosheet at the bottom of the alkaline aqueous electrolyte C for 0.5˜1.5 h.
2. The method according to claim 1 , wherein the mass ratio of epoxy resin to N-N dimethylformamide is 0.1˜2%.
3. The method according to claim 2 , wherein the mass ratio of the epoxy resin to N-N dimethylformamide is 0.5˜1%.
4. The method according to claim 1 , wherein the volume ratio of N-N dimethylformamide solution dissolved with epoxy resin to alkaline aqueous electrolyte C is 1:50˜1:200.
5. The method according to claim 1 , wherein the volume ratio of N-N dimethylformamide solution dissolved with epoxy resin to alkaline aqueous electrolyte C is 1:100˜1:120.
6. The method according to claim 1 , wherein the black phosphorus sheet is pressed by a black phosphorus material through tablet pressing equipment, and the black phosphorus material is one or more of black phosphorus single crystal and black phosphorus powder.
7. The method according to claim 1 , wherein the sulfate is selected from one or more of ammonium sulfate, ammonium bisulfate, sodium sulfate, sodium bisulfate, potassium sulfate, and potassium bisulfate.
8. The method according to claim 1 , wherein the alkaline solution is an ammonia solution, a sodium hydroxide solution, or a potassium hydroxide solution.
9. The method according to claim 8 , wherein the alkaline solution is ammonia, ammonia is added to sulfate solution B to the pH value to 8˜10, the mixed solution is stirred for 15˜20 minutes, and ultrasonication is performed at 15˜30° C. and 30˜60 W for 1˜10 minutes.
10. The method according to claim 1 , wherein the inert electrode is a platinum electrode, a gold electrode, or a carbon rod.
11. The method according to claim 1 , further comprising:
dissolving the precipitate in an organic solvent, and ultrasonicating for 20 to 40 minutes at a power of 30 to 100 W at room temperature to obtain solution D;
centrifuging the D solution at a rate of 2000˜4000 rpm for 20˜40 minutes; and
filtering an upper liquid after centrifugation and cleaning with deionized water for 5˜10 times to obtain a separated solid.
12. The method according to claim 11 , wherein the organic solvent is one or more of N-N dimethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide, and isopropanol, and the amount of the organic solvent is 1-2 ml/mg of the precipitate.
13. The method according to claim 11 , further comprising cleaning and recovering the lower precipitation after centrifugation for reuse.
14. The method according to claim 11 , further comprising:
drying the separated solid to obtain the black phosphorus nanosheet.
15. The method according to claim 14 , wherein the drying is vacuum drying or freeze-drying.