A glassy carbon electrode modified with carbon dots and gold nanoparticles for enhanced electrocatalytic oxidation and detection of nitrite

The authors describe a method for the fabrication of a nanohybrid composed of carbon dots (C-dots) and gold nanoparticles (AuNPs) by in-situ reduction of C-dots and hydroauric acid under alkaline conditions. The process does not require the presence of surfactant, stabilizing agent, or reducing agent. The hybrid material was deposited in a glassy carbon electrode (GCE), and the modified GCE exhibited good electrocatalytic activity toward the oxidation of nitrite due to the synergistic effects between carbon dots and AuNPs. The findings were used to develop an amperometric sensor for nitrite. The sensor shows a linear response in the concentration range from 0.1 μmol⋅L-1 to 2 mmol⋅L-1 and a low detection limit of 0.06 μmol⋅L-1 at the signal-to-noise ratio of 3.