▎ 摘　　要

The fluorescent graphene quantum dots (GQDs) provide an amusing nanoplatform, which integrates unique optical properties of quantum dots and prominent electronic properties of carbon materials. However, rational design of dual functional GQDs has been rarely explored. In this study, we constructed an enzyme-free fluorescent sensing method for catechins in green tea, using bifunctional GQDs, which were employed as the peroxidase-like catalyst and a fluorescence probe. In the presence of dissolved oxygen, GQDs with intrinsic peroxidase-like catalytic activity could catalyze the oxidation of catechins, and the oxidation product could efficiently quench GQDs' fluorescence. Based on this finding, an enzyme-free fluorescent nanoplatform was proposed for the sensing of catechins, and the detection limit of 5.0 nM was found. The integration between the excellent fluorescence performance of GQDs and their high catalytic activity made this sensor a simple and sensitive device for the detection of catechins.