Preparation method of SnO2@Sn coated reduced graphene oxide composite material

A preparation method of SnO2@Sn coated RGO (reduced graphene oxide) composite material, comprising:

• step 1:
• weighing a stannate and an organic compound, and dissolving the stannate and the organic compound in deionized water and organic solvent to obtain a solution with a concentration of 1.0 mol/L, and stirring the solution for 0.5 hours to obtain a milky white solution;
• step 2:
• transferring the milky white solution obtained in step 1 into a polytetrafluoroethylene-lined high-pressure hydrothermal reactor, and holding at 150-220° C. for 15-30 hours;
• step 3:
• cooling the solution in step 2, repeatedly centrifuging the cooled solution with deionized water and anhydrous ethanol at a centrifugal rate of 5000-10000 r/m;
• removing solution to obtain a white precipitate;
• step 4:
• drying the white precipitate obtained in step 3 at 60-120° C. for 12-24 hours to obtain a white powder;
• step 5:
• slowly adding a nitrate to a solution containing a strong acid, and stirring in ice bath for 0.5 hours;
• step 6:
• cooling the solution in step 5 to −10-5° C., slowly adding graphite powder and strong oxidant, stirring in ice bath for 1-5 hours, and after cooling to room temperature, stirring at room temperature for 1-12 hours;
• step 7:
• adding deionized water to the solution obtained in step 6, holding a temperature at 90-100° C., stirring for 0.5 hours, such that a color of the solution obtained in step 6 changes from dark green to bright yellow, and then cooling to room temperature:
• step 8:
• adding an inorganic compound solution with reducibility to the bright yellow solution in step 7, stirring for 1 hour, standing for 10-24 hours, and pouring off a supernatant for 1-5 times;
• step 9:
• adding deionized water to the solution obtained in step 8, and then stirring for 0.5-3 hours, and pouring off a supernatant to obtain a dark yellow solution;
• step 10:
• slowly adding a strong base to the dark yellow solution obtained in step 9 until the dark yellow solution is neutral to obtain a brown solution;
• step 11:
• adding deionized water to the brown solution obtained in step 10, and then stirring for 1-5 hours, and pouring off a supernatant;
• step 12:
• adding an inorganic strong acid to the solution obtained in step 11, washing one time, and stirring for 0.5 hours;
• step 13:
• cooling the solution obtained in step 12, and then centrifuging repeatedly for 0.1-1 hours with deionized water and anhydrous ethanol in a mass ratio of 1:2-8 at a centrifugal rate of 5000-10000 r/m, and pouring off supernatant repeatedly to obtain a black precipitate;
• step 14:
• freeze-drying the black precipitate obtained in step 13 for 12-36 hours to obtain a black powder;
• step 15:
• weighing the white powder obtained in step 4 and the black powder obtained in step 14 with a mass ratio of 3:0.1-10, and dissolving the weighed powder in deionized water, and ultrasonically dispersing for 0.5 hours;
• step 16:
• drying the solution obtained in step 15 at 50-120° C. for 12-36 hours to obtain a black colloid;
• step 17:
• heating the black colloid obtained in step 16 in an inert atmosphere from a temperature of 25° C. to 600-950° C. at a heating rate of 1-5° C./min;
• and then holding for 2-5 hours, and cooling to room temperature naturally to obtain the SnO2@Sn coated reduced graphene oxide composite material (SnO2@Sn@RGO).