Significant improvement in the phenol degradation performance of Ti/PbO2 electrode through La and PVP co-doping strategy

Abstract

In this study, a Ti/PbO₂-La-PVP electrode was prepared by electrodeposition technique for the efficient degradation of phenol by electrochemical oxidation. The rare earth element La has good ductility and during electrolysis forms cavities, vacancies and other defects on the surface of the anode to change and improve the performance of the electrode; Polyvinylpyrrolidone (PVP), as a nonionic surfactant, can prevent the agglomeration of PbO₂ particles, thus increasing the active sites to improve the electrocatalytic efficiency of the electrode. The prepared Ti/PbO₂-La-PVP electrode has a dense and uniform tetrahedral surface with the highest oxygen evolution potential (2.67 V), the largest voltammetric charge capacity (72.31 mC·cm⁻²), the smallest charge transfer resistance (13 Ω·cm⁻²), the longest accelerated lifetime (78 h), and 7.5 times higher •OH production than the unmodified electrode. The optimum process conditions for phenol degradation were investigated, including initial phenol concentration of 1200 mg·L⁻¹, electrolyte concentration of 4.0 g·L⁻¹, current density of 25 mA·cm⁻², electrode spacing of 2.0 cm, Under these conditions, phenol removal rate reached 97.82 % and TOC mineralization rate reached 94.80 % within 180 min. Further, A degradation mechanism is proposed based on intermediate species (catechol, succinic acid, and acrylic acid) identified by HPLC-MS.