▎ 摘　　要

The development of a highly sensitive and selective electrocatalyst for the detection of diclofenac sodium (D.S.) has remained a great challenge. In this work, graphene oxide functionalized with silver nanoparticles and zinc oxide (Ag-ZnO-GO) electrocatalyst was developed and investigated for the detection of D.S. The Ag-ZnO-GO/glassy carbon electrode exhibits high sensitivity and fast response within 3 s owing to the efficient oxidation of D.S. at a very low potential at 0.25 V. Moreover, the electrode shows a low detection limit of 0.02 mu M (S/N = 3) and long-term stability. To explore the synergic effects, the measurements of D.S. using GO, ZnO and ZnO-GO modified electrodes were also performed. The results demonstrate that the Ag-ZnO-GO nanocomposite electrode exhibits enhanced sensitivity and selectivity compared to the other electrodes. In addition, the electrode reveals excellent results for D.S. detection in the real samples as well. The enhanced performance of the proposed electrode is attributed to the improved electron transfer ability and synergic effects of the plasmonic Ag NPs and ZnO-GO structure. It is expected that Ag-ZnO-GO composite is a promising candidate for the construction of cost-effective electrochemical biosensors for medical and industrial applications.