Electrochemical Sensor Based on Ultrasonically Self-Assembled ZIF-8@ZIF-67 and Au Nanoparticles for Simultaneous Detection of 4-aminophenol and Acetaminophen

ZIF-8@ZIF-67 was synthesized using Co 2+ and Zn 2+ as metal sources and 2-methylimidazole as ligand. Nitrogen-doped carbon-based materials (Co-NC) coated with Co nanoparticles were prepared by pyrolysis of ZIF-8@ZIF-67. Co-NC/Au NPs/GCE electrochemical sensor have been prepared by loading Au NPs onto Co-NC via facile ultrasonic self-assembly. The morphology and composition of Co-NC/Au NPs composites were analyzed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and Brunauer–Emmett–Teller analysis. The Co-NC in this sensor inherits the structure and properties of the precursor, which can provide a solid carbon skeleton and abundant active sites, and the large specific surface area provides a loading platform for the introduction of Au NPs. The electrochemical properties of the composites can also be further improved by introducing Au NPs. Based on the experimental results, it was observed that Co-NC/Au NPs/GCE could simultaneously detect 4-AP and ACOP in the range of 1 ∼ 150 μM with the detection limits of 0.064 and 0.053 μM (S/N = 3), respectively. The sensor has achieved the detection of 4-AP and ACOP in industrial wastewater and has shown excellent selectivity, stability, and reproducibility, and has great application prospects.