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, Cu 2 O, and CuS were anchored on g-C 3 N 4 sheets to construct electrochemical sensors for the detection of acetaminophen (AP). The CuX/g-C 3 N 4 nanohybrid composites were analyzed via transmission electron microscopy, infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Among the CuX/g-C 3 N 4 nanocomposites, CuS/g-C 3 N 4 displays a higher electrochemical activity. The electrochemical CuS/g-C 3 N 4 , CuO/g-C 3 N 4 , and Cu 2 O/g-C 3 N 4 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-C 3 N 4 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-C 3 N 4 -based electrochemical sensors display an excellent selectivity, repeatability, reproducibility, and stability. These features suggest that CuX/g-C 3 N 4 based electrochemical sensors can be sensitively detected of AP.