Doping controlled oxygen vacancies of ZnWO4 as a novel and effective sensing platform for carbendazim and biomolecule

Abstract

Oxygen vacancy (VO) is one of the most important defects and acts as the reactive sites in a variety of catalytic reactions. In this work, doping method is employed to generate controllable VO in ZnWO4 crystal and the existence of VO was validated by TEM, XPS and UV–vis absorbance spectra. A novel electrochemical sensor based on Ce-doped ZnWO4 modified carbon paste electrode (CPE) has been fabricated and the electrochemical performance of the proposed sensor is verified by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). The as-prepared oxygen vacancy-rich ZnWO4 shows excellent electrocatalytic performance in sensing carbendazim (CBZ) compared to the virgin CPE. The results demonstrate that VO can effectively enhance electronic conductivity and narrow the band gap, leading to superior performances of 2%Ce-doped ZnWO4 in electrocatalytic reactions. Low detection limits (LOD) of CBZ is obtained to be 0.0033 μmol L−1 via DPV method (S/N = 3). The impressive detection performance is even spread to the simultaneous determination of common neurotransmitters, DA an UA, with detection limits of 0.0033 μmol L−1 and 0.17 μmol L−1 and wide linear range from 0.01 to 30 μmol L−1 and 0.5 to 100 μmol L−1 for DA and UA, respectively.