Insight into CuX (CuO, Cu2O, and CuS) for enhanced performance of CuX/g-C3N4 nanocomposites-based acetaminophen electrochemical sensors

The complexation of metals and metal compounds with organic skeletons into nanohybrid composites attracts attention in electrochemical applications due to the improved charge transfer pathways, which enhance the electrocatalytic activity. In this study, CuO, Cu2O, and CuS were anchored on g-C3N4 sheets to construct electrochemical sensors for the detection of acetaminophen (AP). The CuX/g-C3N4 nanohybrid composites were analyzed via transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Among the CuX/g-C3N4 nanocomposites, CuS/g-C3N4 displays a higher electrochemical activity. The electrochemical CuS/g-C3N4, CuO/g-C3N4, and Cu2O/g-C3N4 sensors have wide linear ranges of 5 to 500 µM with a low detection limit (LOD) of 0.26 µM, 5 to 300 µM with a LOD of 0.32 µM, and 5 to 250 µM with a LOD of 0.47 µM, respectively. The better performance of the CuS/g-C3N4 sensor is probably because of its significantly higher catalytic rate constant with respect to the oxidation of AP in electrochemical kinetics compared with those of the two other sensors, which leads to the enhanced electrocatalytic oxidation of AP. The CuX/g-C3N4-based electrochemical sensors display an excellent selectivity, repeatability, reproducibility, and stability. These features suggest that CuX/g-C3N4 based electrochemical sensors can be sensitively detected of AP.