Zinc oxide thin film based nonenzymatic electrochemical sensor for the detection of trace level catechol

In the present work, a novel zinc oxide thin film based nonenzymatic, electrochemical sensor is developed for the detection of catechol. The zinc oxide thin film electrode on FTO conducting substrate is prepared by a simple and cost effective spin coating technique. The developed sensor exhibits promising cyclic voltammetric as well as amperometric response when the concentration of the catechol in phosphate buffer( pH similar to 7) is varied in the range of 2 to 15 mu M. The interference of the sensor for the detection of catechol is compared in presence of chlorophenol and formaldehyde. The repeatability of the sensor performance towards catechol is also investigated at different time intervals. To understand the underlying mechanism of catechol sensing by the ZnO thin film, we have studied the phase, microstructural and optical features of the electrode before and after electrochemical sensing experiments. It has been observed that the XRD pattern, morphology and optical transmittance of the electrode changes significantly after electrochemical interaction with catechol. Specifically, the 2D thin film morphology upon electrochemical interaction with catechol starts changing to a 1D nanowire like morphology which in turn influences the phase, optical transmittance as well as sensing performance. The modulation of structural, optical features and sensing performances of the developed electrode are again supported by electrochemical impedance spectroscopy.