Voltammetric Sensor Based on Waste-Derived Carbon Nanodots for Enhanced Detection of Nitrobenzene

Carbon dots (CDs) samples were synthesized from orange peel waste (OPW) via a simple and eco-friendly hydrothermal carbonization (HTC) and electrochemical (EC) bottom-up synthesis integrated approach. The comprehensive chemical-physical characterization of CDs samples, carried out by various techniques such as TEM, EDX, XRD, FT-IR, underlined their morphological and microstructural features. The CDs exhibited attractive electrochemical properties, and thus an electrochemical sensor by modifying a screen printed carbon electrode (CDs/SPCE) for the detection of nitrobenzene (NB) in water was developed. Electroanalytical performances of CDs/SPCE sensor using differential pulse voltammetry (DPV) demonstrated its high sensitivity (9.36 μA μM−1 cm−2) towards NB in a wide linear dynamic range (0.1–2000 μM) and a low limit of detection (LOD=13 nM). The electrochemical sensor also shown high selectivity, long-term stability, and repeatability. This paper might open the way to a new synergistic HTC-EC approach for the synthesis of CDs from waste biomass material and their advanced application in highly efficient electrochemical sensors.