▎ 摘　　要

NOVELTY - Preparation of photothermal nanocomposite based on graphene oxide by mixing flake graphite and sodium nitrate, stirring sulfuric acid, mixing potassium permanganate, reacting, adding water and hydrogen peroxide, hot filtering, washing with water, neutralizing with hydrochloric acid, centrifuging, and vacuum drying; adding graphene oxide to distilled water, peeling off, centrifuging, adding precipitate to water, and combining supernatant; dialyzing, and taking filtrate; uniformly dispersing graphite oxide dispersion, adding sodium hydroxide and sodium hypochlorite, converting hydroxyl group on graphene oxide sheet into carboxyl group, neutralizing, centrifuging, collecting upper black solution and dialyzing; adding folic acid to solution, dispersing, adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide and nitrogen, sonicating, and dialyzing; rotary evaporating, washing with acetone, and vacuum drying; and mixing folic acid modified graphene oxide with chloroauric acid solution and aging. USE - The method is used for preparing photothermal nanocomposite based on graphene oxide. DETAILED DESCRIPTION - Preparation of photothermal nanocomposite based on graphene oxide comprises weighing 5-8 g flake graphite and 2-5 g sodium nitrate, mixing, adding 120-150 mL concentrated sulfuric acid in ice bath, stirring, adding 20-25 g potassium permanganate, mixing for 30-40 minutes, reacting for 60-70 minutes, transferring to warm bath of 40-45 degrees C for 30-40 minutes, slowly adding 230-250 mL deionized water, keeping reaction temperature at 96-98 degrees C, stirring for 3-5 minutes, adding hydrogen peroxide until no bubbles are formed, hot filtering, washing with deionized water, neutralizing with 5-7 wt.% hydrochloric acid, centrifuging, and vacuum drying to obtain graphite oxide; adding 50-60 mg graphene oxide to 50-60 mL distilled water in ice bath, peeling off by ultrasonic vibration to obtain brownish yellow dispersion, centrifuging to collect brownish yellow supernatant, adding precipitate to distilled water, and combining supernatant to obtain aqueous graphene oxide solution; dialyzing against distilled water for 2-3 days, and taking filtrate; uniformly dispersing graphite oxide dispersion by ultrasonication, adding 5-7 g sodium hydroxide and 5-7 g sodium hypochlorite, converting hydroxyl group on graphene oxide sheet into carboxyl group by ultrasonic treatment for 1-3 hours, neutralizing with dilute hydrochloric acid, repeatedly rinsing, centrifuging, collecting upper black solution and dialyzing against deionized water for 40-50 hours to remove unreacted water-soluble substances; adding 0.5-0.8 g folic acid to solution, uniformly dispersing ultrasonically, and adding 125-127 mg 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 182.5-184.5 mg nitrogen while stirring, sonicating for 2-3 hours, performing dialysis treatment with sodium bicarbonate solution, changing water every 3-5 hours, and performing dialysis for 40-50 hours to obtain black solution; removing water in black solution by rotary evaporation, repeatedly washing with acetone, and vacuum drying at 40-50 degrees C to obtain folic acid modified graphene oxide; and mixing folic acid modified graphene oxide with chloroauric acid solution, aging for 25-35 minutes, heating to 80-85 degrees C, adding 470-480 mu L 0.48-0.5 mM sodium citrate solution dropwise, stirring for 60-80 minutes, cooling to room temperature, centrifuging, discharging supernatant, and washing precipitates.