▎ 摘　　要

NOVELTY - Preparation of nanosilver/graphene composite, involves (a) dissolving polyvinylpyrrolidone (PVP) powder and surfactant in N-methyl-2-pyrrolidone (NMP) solution, adding expanded graphite and uniformly dispersing to obtain a single-layer graphene NMP solution, (b) preparing nanosilver/graphene composite by dropping the aqueous silver nitrate solution in single-layer graphene NMP solution, shaking, dropping the aqueous tannic acid solution and stirring the solution, and (c) washing the nanosilver/graphene composite with deionized water by centrifuging the solution. USE - The method is useful for preparation of nanosilver/graphene composite. ADVANTAGE - The prepared nanosilver/graphene composite has physical enhancement effect of silver particles and chemical enhancement effect of graphene, and extremely strong surface-enhanced Raman scattering (SERS) activity. The method is simple to perform, and suitable for wide popularization and application. DETAILED DESCRIPTION - Preparation of nanosilver/graphene composite, involves (a) preparing graphene N-methyl-2-pyrrolidone (NMP) solution by dissolving polyvinylpyrrolidone (PVP) powder and surfactant with molecular weight of 5000 in NMP solution, then adding expanded graphite in the NMP solution, uniformly dispersing by ultrasound to obtain a single-layer graphene NMP solution, where the PVP concentration is 0.01-0.05 g/ml, and the content of graphene is 0.02-0.1 g/l, (b) preparing nanosilver/graphene composite by preparing aqueous silver nitrate solution and aqueous tannic acid solution with same concentration, dropping the aqueous silver nitrate solution in the single-layer graphene NMP solution, where the mass ratio of silver nitrate and tannic acid is 10-100, shaking and dropping the aqueous tannic acid solution in the solution, and stirring to obtain a nanosilver/graphene composite with silver particle of 20-30 nm, where the dosage of the tannic acid is 3-8 times of that of the aqueous silver nitrate solution, and (c) washing the nanosilver/graphene composite with deionized water by centrifuging to obtain the nanosilver/graphene composite.