An electrochemical sensor based on FeCo2O4@ZIF-67/MWCNT-COOH for simultaneous detection of dihydroxybenzene isomers in different water systems

Abstract

Simultaneous determination of dihydroxybenzene isomers is of great value for environmental monitoring, but it is still full of challenges. In this study, ZIF-67 was grown locally in FeCo₂O₄ nanospheres by a one-pot method, and a new-style electrochemical sensing platform, FeCo₂O₄@ZIF-67/MWCNT-COOH/GCE, was constructed by adding MWCNT-COOH to achieve signal amplification and simultaneous detection of hydroquinone (HQ), catechol (CC) and resorcinol (RC). Benefitting from the high catalytic activity of FeCo₂O₄ with the large specific surface area and orderly pore structure of MOFs, the obtained composite FeCo₂O₄@ZIF-67 showed obvious synergies, which significantly improved the sensitivity of the sensor. Due to the fast electron transport, abundant active sites and excellent electrocatalytic performance of the modified electrode, the sensor exhibited wide linear ranges (2–450 μM for HQ and CC and 8–450 μM for RC) and low detection limits for these three analytes (0.17 μM HQ, 0.19 μM CC and 0.39 μM RC). More importantly, the proposed electrochemical sensor showed excellent detection performance in complex water samples and provided a potential strategy for the analysis of other toxic substances in the ecological environment.