Electrochemical fabrication and preliminary examination of modified lead dioxide bulk and analytical electrodes

摘要

The article describes the electrochemical fabrication of modified lead dioxide (PbO2) electrodes through a simple but efficient electrodeposition method. One of the goals was to assess the properties of the modified PbO2 as an electroanalytical electrode. A second objective was its use in bulk electrolysis against persistent organic pollutants in water. PbO2 was deposited galvanostatically at a current density of 10 mA cm~(-2) over the as-obtained and anodized Pd/Ag alloy substrate at 10 V. The electroanalytical studies of the modified PbO2 showed satisfactory electrochemical activity for ferrocene compared to that on commercial glassy carbon. The modified PbO2 electrode having an area of 4 cm2 was employed to eradicate phenol and 2-nitrophenol from water samples. 2-Nitrophenol was completely removed (99 %) and phenol (>50 %) was partially removed by bulk electrolysis at the optimized current density of 20 mA cm~(-2) for 3 h. Incomplete degradation in the latter case was due to the adsorption of electrochemically generated intermediates. The degradation monitoring was performed by cyclic voltammetry, UV-vis spectroscopy, and HPLC methods and the results were in good agreement with each other. The assays and morphological studies by SEM revealed the role of Nafion in the modified PbO2 electrode for efficient degradation of phenols through the bulk electrolysis.