▎ 摘　　要

NOVELTY - Preparing graphene using persimmon tannin as reducing agent comprises (i) passing natural immature persimmon through 60 meshes sieve, adding deionized water and enzyme, carrying out ultrasonic extraction process, vacuum filtering the extract liquid, and drying to obtain persimmon tannin; (ii) dispersing graphite oxide in deionized water, and processing ultrasonic treatment for 10-24 hours to obtain graphene oxide solution; and (iii) mixing 0.01-10 vol.% persimmon tannin aqueous solution, and 0.01-0.05 g/l graphene oxide solution, and subjecting to ultrasonic treatment. USE - The method is useful for preparing graphene using persimmon tannin as reducing agent (claimed). ADVANTAGE - The method: adopts enzyme-ultrasonic assisted extraction process for extracting persimmon tannin; does not require high-temperature; has good safety, short time and high-efficiency when compared with conventional solvent extraction method; utilizes graphene oxide as raw material; utilizes environmentally-friendly persimmon tannin as reducing agent; does not add any stabilizer and dispersing agent; and provides graphene aqueous solution having good dispersibility and stability. DETAILED DESCRIPTION - Preparing graphene using persimmon tannin as reducing agent comprises (i) passing natural immature persimmon through 60 meshes sieve, adding deionized water and 0.1-0.5 wt.% enzyme, carrying out ultrasonic extraction process at 30-50 degrees C under ultrasonic power of 80-120 w for 10-60 minutes, where enzymolysis pH value is 5-6, and the material liquid ratio is 1:5-1:20, vacuum filtering the extract liquid, and drying to obtain persimmon tannin; (ii) dispersing graphite oxide in deionized water, and processing ultrasonic treatment for 10-24 hours to obtain graphene oxide solution; and (iii) mixing 0.01-10 vol.% persimmon tannin aqueous solution, and 0.01-0.05 g/l graphene oxide solution, and subjecting to ultrasonic treatment at 60-80 degrees C to obtain the graphene solution.