Carbon-black-coupled bimetallic CoCu-ZIF composites for monohydroxylated polycyclic aromatic hydrocarbon metabolite sensing

Abstract Polycyclic aromatic hydrocarbons are hazardous, carcinogenic pollutants produced by the incomplete combustion of organic materials, and their detection remains a technological challenge. Here, we develop bimetallic cobalt-and-copper-based zeolitic imidazolate framework (CoCu-ZIF) particles coupled with carbon black (CB) for highly sensitive and selective electrochemical sensing of 2-Naphthol, a monohydroxylated polycyclic aromatic hydrocarbon. The CoCu-ZIF with dual redox-active sites of Co 3+ /Co 2+ and Cu 2+ /Cu + promotes efficient electron transfer during the oxidation process, thus effectively catalyzing the oxidation of 2-Naphthol. Carbon black provides a conductive network facilitating efficient electron transport between CoCu-ZIF and electrode surface. The fabricated sensors exhibit a sensitivity and limit of detection of 0.98 µA µM⁻¹ and 0.46 µM, respectively, during exposure to 2-Naphthol within a detection range of 1–500 µM. Moreover, due to their excellent sensing performance, selectivity, reproducibility, and recovery rate in non-biological urine, the developed composites offer strong potential for real-time polycyclic aromatic hydrocarbon monitoring and future use in environmental sensor technologies.