A nano-lead dioxide-composite electrochemical sensor for the determination of chemical oxygen demand

Chemical oxygen demand (COD) is a critical analytical parameter for organic pollutants in the aqueous system. Most COD detection methods have disadvantages such as virulence, time-consuming and complicated steps, which makes the exploration of suitable COD detection methods an important challenge. In this work, a novel nano-PbO 2 -composite electrochemical sensor was fabricated, and its electrochemical sensing properties for COD detection were investigated. The surface morphology and construction of nano-PbO 2 -composite electrodes were investigated using scanning electron microscope (SEM) and X-ray diffraction (XRD), which showed that the substrates were completely covered by nano-PbO 2 . The linear sweep voltammetry (LSV), the hydroxyl radical (·OH) generation ability, and electrochemical impedance spectroscopy (EIS) were employed to study the electrochemical properties. Good analytical characteristics in standard glucose solutions were achieved with Ti b /SnO 2 -Sb 2 O 3 / β -PbO 2 sensor. In particular, Ti b /SnO 2 -Sb 2 O 3 / β -PbO 2 showed a good correlation between the sensor response and the COD values, which exhibited a linear range from about 500–9000 mg·L −1 . Generally, the nano-PbO 2 sensor displayed fast-response speed and simple instrumentation, which is promising for the COD determination with low cost, high detection sensitivity, and wide linear range.