A sensitive enzyme-free hydrogen peroxide sensor based on a chitosan–graphene quantum dot/silver nanocube nanocomposite modified electrode

Abstract

Graphene quantum dots (GQDs) and silver nanocubes (AgNCs) were synthesized successfully and characterized by UV-vis and fluorescence (FL) spectra, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The GQDs and AgNCs modified gold electrode (GE) possesses good conductivity shown by electrochemical impedance spectroscopy (EIS). The Chit–GQDs/AgNCs/GE displays a good electrocatalytic activity towards the reduction of hydrogen peroxide (H₂O₂), and can be used as a novel and sensitive enzyme-free H₂O₂ sensor. According to the amperometric experiments, the sensor exhibits a rapid response, a wide linear range from 10 μM to 7.38 mM, a low detection limit of 0.15 μM and high selectivity, as well as a good repeatability for H₂O₂ determination.