In Situ Growth of Silver Nanoparticles on Graphene Quantum Dots for Ultrasensitive Colorimetric Detection of H_2O_2 and Glucose

摘要

We report a facile green approach for in situ growth of silver nanoparticles (AgNPs) on the surface of graphene quantum dots (GQDs). GQDs serve as both reducing agent and stabilizer, and no additional reducing agent and stabilizer is necessary. The GQDs/AgNPs hybrid exhibits a superior absorbance fading response toward the reduction of H_2O_2. A simple colorimetric procedure is thus proposed for ultrasensitive detection of H_2O_2 without additional chromogenic agent. It provides a record detection limit of 33 nM for the detection of H_2O_2 by the AgNPs-based sensing system. This colorimetric sensing system is further extended to the detection of glucose in combination with the specific catalytic effect of glucose oxidase for the oxidation of glucose and formation of H_2O_2, giving rise to a detection limit of 170 nM. The favorable performances of the GQDs/AgNPs hybrid are due to the peroxidase-like activity of GQDs.