Nonenzymatic amperometric sensing of hydrogen peroxide using a glassy carbon electrode modified with a sandwich-structured nanocomposite consisting of silver nanoparticles, Co3O4 and reduced graphene oxide

A sandwich structured nanocomposite consisting of mildly reduced graphene oxide modified with silver nanoparticles supported on Co3O4 was synthesized and used for fabricating a nonenzymatic sensor for H2O2. The morphology and composition of the nanocomposite was characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction and FTIR. The composite was placed on a glassy carbon electrode which then displayed excellent performance in terms of electroreduction of H2O2. The H2O2 sensor, if operated at pH 7.4 at a working potential of 0.4 V (vs. SCE) has the following features: (a) linearity in the 0.1 mu M to 7.5 mM concentration range; (b) a sensitivity of 146.5 mu Aa (TM) mMaEuro3/4(1)a (TM) cmaEuro3/4(2); (c) a 35 nM detection limit at a signal-to-noise ratio of 3, and (d) a response time of 2 s. The sensor is long-term stable, well reproducible and selective.