▎ 摘　　要

NOVELTY - Method for preparing nano-graphene having three-dimensional structure, involves (a) performing hydrothermal reaction on graphene oxide dispersion at 130-150degrees Celsius in closed environment for 10-15 hours, and cooling to obtain reduced graphene oxide hydrogel, and (b) freeze-drying reduced graphene oxide hydrogel, and calcining at 740-760degrees Celsius for 4-6 hours to obtain nano-graphene having three-dimensional structure. USE - The method is used for preparing nano-graphene having three-dimensional structure used for preparing air-purifying inorganic coating (claimed). ADVANTAGE - The air-purifying inorganic coating has excellent ability to purify haze. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a nano-graphene having three-dimensional structure prepared using above-mentioned method. (2) an air-purifying inorganic coating comprising 200-300 pts. wt. water, 3-6 pts. wt. cellulose, 1-2 pts. wt. bentonite, 3-6 pts. wt. dispersant, 2-4 pts. wt. wetting agent, 2-4 pts. wt. defoamer, 150-200 pts. wt. titanium dioxide, 50-100 pts. wt. kaolin, 200-250 pts. wt. heavy calcium carbonate, 250-350 pts. wt. silica sol solution, 50-150 pts. wt. potassium silicate, 6-10 pts. wt. multifunctional regulator, 2-5 pts. wt. thickener and 20-50 pts. wt. nano-graphene with three-dimensional structure. (3) a method for preparing the purified air-type inorganic coating, involving (a) preliminarily mixing bentonite, cellulose, dispersant, wetting agent, defoamer and water to obtain mixture, (b) uniformly mixing nano-graphene, titanium white powder, kaolin, heavy calcium carbonate and mixture in three-dimensional structure for second time to obtain stock solution, (c) uniformly mixing silica sol solution, potassium silicate and feed liquid for third time to obtain coating slurry, and (d) uniformly mixing multifunctional regulator, thickener and coating slurry for fourth time to obtain purified air-type inorganic coating.