Construction And Application Of Electrochemical Sensing Interface Based On Rare Earth Doped Nanocrystalline Structure

The highly sensitive analysis and detection of environmental organic pollutants possessed a great significance.In recent years,the electrochemical analysis method has been widely used in the detection of BPA and CBZ.As the core device of this method,the electrochemical sensor was focused on improving the electrocatalytic performance of the electrode material.In this paper,based on three rare earth elements doped inorganic nanomaterials,a new type of highly sensitive electrochemical sensor for detecting typical organic pollutants was constructed.Based on the doping principle and crystal structure of inorganic nanomaterials,the mechanism of electrocatalysis was speculated.The main research contents are as follows:?1?Rare earth Ce-doped ZnO nanorods were successfully synthesized via the hydrothermal method.Scanning electron microscopy?SEM?and X-ray diffraction?XRD?results indicated that Ce ions were successfully doped into ZnO lattice and resulted in smaller nanorods and larger crystallite size,which was advantageous for the improvement of electrocatalytic performance.A highly sensitive and selective sensor for the determination of bisphenol A?BPA?has been strategically designed based on the Ce-doped ZnO nanorods.Furthermore,the electrochemical performances of the Ce-doped ZnO modified CPE?Ce-doped ZnO/CPE?are studied by cyclic voltammetry?CV?,electrochemical impedance spectroscopy?EIS?and differential pulse voltammetry?DPV?and the electrochemical responses are significantly improved.The oxidation peak currents of BPA are in good linear relationship to its concentrations in the ranges of 0.5-3.2?M and 3.2-62.0?M and the detection limit for BPA is 0.018?M,indicating that the modified electrode has good electrocatalytic effect for BPA.?2?Crystal structure modification was introduced into CdWO₄ via La doping strategy and the characterization results of SEM,XRD,TEM and EDS confirmed the morphology,crystal phase structure and composition of the CdWO₄ and La-doped CdWO₄ nanorods.Meanwhile,the partial substitution of Cd by La ions in CdWO₄ nanocrystal was confirmed via some classic formulas.Excellent electrocatalytic performance was obtained on the electrochemical sensing interface when the La ions were doped into the CdWO₄ lattice.The regular rod-like 1.0%La-doped CdWO₄ modified electrochemical sensor was applied to detect BPA and a highly sensitive detection limit of 0.02?M was established,and verified the more excellent electrocatalytic activity of 1.0%La-doped CdWO₄ than other doping nanomaterials.The possible mechanism of the electrochemical catalysis of BPA was proposed based on the effective electrochemical analysis methods?EIS,CV and I-T?and various physicochemical characterizations.More electron transmission channels were formed in the crystal due to the moderate amount of La ions in CdWO₄ nanorods.?3?Er₂O₃ and Yb-doped Er₂O₃ nanomaterials synthesis via hydrothermal method showed a uniform and regular mixture of nanorods and nanosheets.The specific mechanism of doping Yb element in cubic Er₂O₃ nanocrystals had been speculated via analysis of phase characterization results and calculation of crystal parameters.EIS,CV and DPV methods were used to investigate the electrochemical behavior of carbapenem?CBZ?on Yb doped Er₂O₃/CPE modified electrode.The results showed that Yb doping makes Er₂O₃ own higher electrocatalytic ability.This may be attributed to the formation of oxygen vacancies and point defects in the nanocrystals caused by the doping of rare earth element Yb.Moreover,CBZ electrochemical sensor based on Yb doped Er₂O₃ nanometer material shows many advantages,such as low detection limit,high sensitivity and wide linear range.