Copper Metal Organic Framework and Graphitic Carbon Nitride Nanocomposite Modified Electrochemical Interface for Voltammetric Sensing of Hazardous <i>p</i> -Benzoquinone

Para-benzoquinone (PBQ) is a harmful pollutant that can negatively affect both water life and human health. It is known to be cytotoxic and mutagenic. PBQ often enters water bodies through industrial waste and from the breakdown of other toxic pollutants. Accordingly, there is a strong need for fast, accurate, and reliable methods to detect PBQ in water. In this study, a highly stable and electrocatalytically active electrochemical sensor is developed by modifying a glassy carbon electrode with copper(II) benzene-1,3-dicarboxylate and graphitic carbon nitride (CuBDC.gCN) nanocomposite via a controlled electrodeposition technique. The structural and morphological features of CuBDC.gCN composite and its electrodeposited interface are elucidated through extensive characterizations, including X-ray diffraction, infrared spectroscopy, scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy. Square wave voltammetry and cyclic voltammetry are employed to evaluate the sensor’s electrochemical response. CuBDC.gCN|GCE displayed exceptional electrocatalytic performance toward PBQ, evidenced by a 31.7-fold enhancement in peak current and a notable negative shift of 0.13 V, compared to bare GCE. The sensor exhibited high sensitivity, with a wide linear detection range of 2.5–100.0 μM and a low detection limit of 38.2 nM. The sensor exhibited excellent selectivity, repeatability, and reproducibility, affirming its practical applicability for the interference-free, electrochemical monitoring of PBQ in environmental samples.