Switched electrochemical sensor for hydroquinone based on rGO@Au, monoclinic BiVO4 and temperature-sensitive polymer composite material

Abstract

In this paper, a temperature-controlled “On-Off” electrochemical sensor for the detection of hydroquinone (HQ) is constructed by using a composite film of temperature-sensitive polymer poly (N-vinylcaprolactam) (PNVCL), the nanomaterial rGO@Au and the monoclinic bismuth metavanadate (m-BiVO4). The sensor exhibits good temperature sensitivity and reversibility. When the temperature drops below the Lowest Critical Solution Temperature (LCST) of the PNVCL, the PNVCL will be in a “stretched” state, which hinders the electron exchange between hydroquinone and the surface of the electrode, presenting an “Off” state for the sensor. On the contrary, when the temperature exceeds the LCST, the PNVCL will be in a “contracted” state, which hydroquinone can perform an effective redox process and generate a response current, showing an “On” status. Due to the good electroconductivity and electrocatalytic ability of rGO@Au and m-BiVO4, the proposed sensor showed excellent detection performances. Hence, the sensor shows wide linear ranges (2.0 to 30.0 μM and 30.0 to 152.0 μM) and low limit of detection (0.6 μM). In addition, the “On-Off” electrochemical sensor may provide new ideas for the application of intelligent polymers.