▎ 摘　　要

NOVELTY - Preparing three-dimensional boron-nitrogen co-doped graphene aerogel comprises (i) preparing graphene oxide using modified Hummer's method; (ii) preparing polyhydroxy boron nitride using atomic replacement method; and (iii) preparing three-dimensional boron-boron co-doped graphene aerogel by dispersing graphene oxide in deionized water, to obtain aqueous graphene oxide dispersion having a concentration of 2-6 mg/ml, and dispersing polyhydroxy boron nitride in isopropanol, to obtain polyhydroxy boron nitride isopropanol dispersion having a concentration of 2-6 mg/ml. USE - The method is useful for preparing three-dimensional boron-nitrogen co-doped graphene aerogel (claimed). ADVANTAGE - The aerogel has larger specific surface area, pore structure and active site. DETAILED DESCRIPTION - Preparing three-dimensional boron-nitrogen co-doped graphene aerogel comprises (i) preparing graphene oxide using modified Hummer's method comprising (i.a) placing 25 ml concentrated sulfuric acid in a ice bath, adding 1.2 g graphite sheet under stirring conditions, until complete dispersion, rising temperature to 35 degrees C and stirring for 2 hours, (i.b) adding 40 ml deionized water slowly with a syringe, placing in 95 degrees C oil bath, carrying out reaction for 30 minutes, removing heat source, then adding 100 ml deionized water and diluting, adding 3 ml hydrogen peroxide dropwise, and removing remaining potassium, and (i.c) cooling the step (i.b) product to room temperature, centrifuging, to obtain a yellow solid, uniformly mixing with 10% hydrochloric acid, centrifuging and washing (3 times) with deionized water, placing the solid in a vacuum oven, drying at 35 degrees C, to obtain graphene oxide; (ii) preparing polyhydroxy boron nitride using atomic replacement method comprising (ii.a) placing 3 g dicyandiamide in a tube furnace, sintering under nitrogen atmosphere, rising temperature to 500 degrees C at the heating rate of 2.2 degrees C/minute, insulating for 4 hours, cooling naturally to room temperature, to obtain graphitic carbon nitride (g-C3N4) powder, (ii.b) uniformly mixing 3 g g-C3N4 powder and 0.9 g boric acid with 100 ml deionized water, subjecting to ultrasonic dispersion for 30 minutes, dispersing, evaporating at 100 degrees C, to obtain dry g-C3N4/boric acid mixture, and (ii.c) placing g-C3N4/boric acid mixture in a tube furnace, sintering under nitrogen atmosphere at the heating rate of 3.3 degrees C/minute to 800 degrees C for 1 hour, cooling naturally to room temperature, to obtain polyhydroxy boron nitride; and (iii) preparing three-dimensional boron-boron co-doped graphene aerogel comprising (iii.a) dispersing 20-60 mg graphene oxide in 10 ml deionized water, to obtain aqueous graphene oxide dispersion having a concentration of 2-6 mg/ml, (iii.b) dispersing 20-60 mg polyhydroxy boron nitride in 10 ml isopropanol, to obtain polyhydroxy boron nitride isopropanol dispersion having a concentration of 2-6 mg/ml, (iii.c) uniformly mixing step (iii.a) and (iii.b) products, subjecting to ultrasonic dispersion for 30-60 minutes, to obtain graphene oxide/polyhydroxy boron nitride/water/isopropanol dispersion, where the mass ratio of graphene oxide and polyhydroxy boron nitride is 1:2-4:1 and volume ratio of water and isopropanol is 1:1-4:1, (iii.d) placing step (iii.c) product in a hydrothermal autoclave, heating to 150-200 degrees C for 2-12 hours, cooling naturally, washing with deionized water, to obtain complex hydrogel, and (iii.e) placing step (iii.d) product in a refrigerator, freezing for 12 hours, then adding into a freeze dryer, vacumm freezing at 20-25 degrees C for 48-72 hours, to obtain the final product.