▎ 摘　　要

An Ag-graphene nanocomposite was firstly prepared using a one-step thermal reduction, then an Ag@Pt core-shell nanostructure was obtained via a galvanic replacement reaction. The Ag@Pt-graphene nanocomposite was successfully synthesized and further fabricated into an electrochemical sensor of H2O2. Its electrochemistry and electrocatalytic behavior towards H2O2 were investigated. The results exhibited that this sensor had excellent electrocatalytic properties towards H2O2. The reduction peak current signals had a good linear dependence on H2O2 concentration in the range from 5.0 mu mol L-1 to 12.4 mmol L-1, and the detection limit was 0.9 mu mol L-1 (S/N = 3). The preparation method is environmentally friendly and can make Ag, Pt and graphene nanomaterials become a unified whole, introducing a synergistic effect between the nanoparticles effectively, leading to a superior electrocatalytic ability compared to GO or the Ag-graphene nanocomposite. The results indicate that the Ag@Pt-graphene nanocomposite has great application potential for use in electrochemical sensors.