Ti/PANI/PbO₂-Ce Anode for 2,3-Dimethylphenol Degradation: Effective Electrocatalytic Performance and Degradation Mechanism

A novel Ti/PANI/PbO₂-Ce electrode was fabricated using the electrodeposition method for the degradation of 2,3-dimethylphenol, a typical phenolic pollutant in coking wastewater. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and x-ray diffraction (XRD) analyses confirmed the successful incorporation of Ce into the PbO₂ matrix. The polyaniline (PANI) interlayer significantly enhanced the electrode's stability and service lifetime. The addition of the rare earth element Ce resulted in the formation of a three-dimensional spherical PbO₂ structure, increasing the electrode's surface area and reducing the PbO₂ grain size. Compared to the conventional Ti/PbO₂ electrode, the Ti/PANI/PbO₂-Ce electrode exhibited a higher oxygen evolution potential (OEP, 1.91 V), larger specific surface area, lower charge transfer resistance, and superior hydroxyl radical (•OH) generation capacity. The degradation conditions for 2,3-dimethylphenol were optimized through single-factor experiments, achieving a degradation efficiency of 99.86% at a voltage of 14 V, plate spacing of 1.5 cm, Na₂SO₄ electrolyte concentration of 0.25 mol/L, pH of 10, and reaction time of 120 min. The calculated activation energy (Ea) and thermodynamic parameters indicate that the electrocatalytic process is an endothermic process. The efficient anodic oxidation of 2,3-dimethylphenol was primarily driven by indirect •OH oxidation. Potential degradation pathways of 2,3-dimethylphenol were elucidated through UV–visible spectrophotometry and gas chromatography-mass spectrometry (GC–MS) analysis of the degradation intermediates.