Fabrication and characterization of PbO2 electrode modified with [Fe(CN)6]3− and its application on electrochemical degradation of alkali lignin

PbO2 electrode modified by [Fe(CN)6]3− (marked as FeCN–PbO2) was prepared by electro-deposition method and used for the electrochemical degradation of alkali lignin (AL). The surface morphology and the structure of the electrodes were characterized by scanning electronic microscopy (SEM) and X-ray diffraction (XRD), respectively. The stability and electrochemical activity of FeCN–PbO2 electrode were characterized by accelerated life test, linear sweep voltammetry, electrochemical impedance spectrum (EIS) and AL degradation. The results showed that [Fe(CN)6]3− increased the average grain size of PbO2 and formed a compact surface coating. The service lifetime of FeCN–PbO2 electrode was 287.25 h, which was longer than that of the unmodified PbO2 electrode (100.5 h). The FeCN–PbO2 electrode showed higher active surface area and higher oxygen evolution potential than that of the unmodified PbO2 electrode. In electrochemical degradation tests, the apparent kinetics coefficient of FeCN–PbO2 electrode was 0.00609 min−1, which was higher than that of unmodified PbO2 electrode (0.00419 min−1). The effects of experimental parameters, such as applied current density, initial AL concentration, initial pH value and solution temperature, on electrochemical degradation of AL by FeCN–PbO2 electrode were evaluated.