An electrochemical sensor based on oxygen-vacancy cobalt–aluminum layered double hydroxides and hydroxylated multiwalled carbon nanotubes for catechol and hydroquinone detection

A sensitive electrochemical sensor based on oxygen vacancy Co-Al layered double hydroxides (OV-LDHs) and hydroxylated multi-walled carbon nanotubes (H-MWCNTs) was developed by self-assembly method. The existence of oxygen vacancy improved the poor electrochemical performance of original LDHs. In addition, the surface of the hydroxylated MWCNTs was rich in hydroxyl functional groups, which enabled them to form hydrogen bonds with the oxygen containing groups on the surface of the OV-LDHs, thus leading to the formation of stable nanocomposite. The electrode modified with OV-LDHs/H-MWCNTs was used for detection of hydroquinone (HQ) and catechol (CT). Under optimum experimental condition, the detection linear range of the electrochemical sensor was both 0.5–150 μM. The limit of detection (S/N = 3) for CT and HQ were as low as 0.074 μM and 0.076 μM, respectively. In addition, the OV-LDHs/H-MWCNTs sensor was explored to determine the content of HQ and CT in industrial wastewater, and satisfying recoveries were obtained. Therefore, this innovative sensor with excellent electrochemical performance is indeed an option for practical detection of organic pollutants in the environment.