Even though there have been a variety of electrochemical sensors, it is of great importance to search for a nanomaterial with efficient active sites and explain its mechanism in the electrochemical detection of heavy metals. In the present research work, flower-like oxygen vacancy-rich zinc oxide (OV-ZnO) is prepared by processing flower-like ZnO (ZnO) with plasma. The presence of oxygen vacancies is validated using X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and Raman spectroscopy. The prepared OV-ZnO is then used to modify the glassy carbon electrode (GCE) surface to construct an electrochemically sensitive interface for detecting Hg(II). According to the obtained results, oxygen vacancies can significantly improve the sensing performance of the electrode for Hg(II) detection, achieving a detection sensitivity of up to about 1323.91 μA·μM⁻¹·cm⁻² and a detection limit of approximately 0.023 μM. In addition, OV-ZnO revealed good anti-interference performance against common heavy metal ions and showed excellent stability and reproducibility. XPS and density-functional theory calculations suggest that its good electrochemical sensing performance could possibly be due to the activation of oxygen vacancies, the low adsorption energy, and the appropriate Hg-Zn bond length. Moreover, the OV-ZnO-modified GCE exhibits high sensitivity to Hg(II) in actual water samples, which offers theoretical guidance for constructing electrochemical sensors for practical applications in the future.

尽管已经有各种各样的电化学传感器，但寻找具有高效活性位点的纳米材料并解释其在电化学检测重金属中的作用机制是非常重要的。本研究工作采用等离子体处理花状氧化锌（ZnO）制备花状富氧空位氧化锌（OV-ZnO）。使用 X 射线光电子能谱 (XPS)、电子自旋共振 (ESR) 和拉曼光谱验证氧空位的存在。然后将制备的 OV-ZnO 用于修饰玻碳电极 (GCE) 表面以构建用于检测 Hg(II) 的电化学敏感界面。根据获得的结果，氧空位可以显着提高电极对Hg（II）检测的传感性能，^-1 ·cm ^-2和大约0.023 μM的检测限。此外，OV-ZnO对常见重金属离子表现出良好的抗干扰性能，并表现出优异的稳定性和重现性。XPS和密度泛函理论计算表明，其良好的电化学传感性能可能是由于氧空位的活化、低吸附能和适当的Hg-Zn键长。此外，OV-ZnO修饰的GCE对实际水样中的Hg(II)表现出较高的敏感性，这为未来构建用于实际应用的电化学传感器提供了理论指导。