▎ 摘　　要

Nanostructured electrochemical sensors often suffer from irreversible aggregation and poor adhesion to the supporting materials, resulting in reduced sensitivity and selectivity over time. We describe a versatile method for fabrication of a H2O2 sensor by immobilizing copper nanoparticles (Cu NPs; 20 nm) on graphene oxide ( GO) sheets via in-situ reduction of copper(II) on a polydopamine (PDA) coating on a glassy carbon electrode. The PDA film with its amino groups and catechol groups acts as both a reductant and an adhesive that warrants tight bonding between the Cu NPs and the support. The modified electrode, best operated at a working voltage of -0.4 V ( vs. Ag/AgCl), has a linear response to H2O2 in the 5 mu M to 12 mM concentration range, a sensitivity of 141.54 mu A.mM(-1).cm(-2), a response time of 4 s, and a 1.4 mu M detection limit ( at an S/N ratio of 3). The sensor is highly reproducible and selective ( with minimal interference to ascorbic acid and uric acid). The method was applied to the determination of H2O2 in sterilant by the standard addition method and gave recoveries between 97% and 99%.