Synergistic defect engineering in TiO2 nanotubular electrodes for advanced electrochemical oxidation of benzene-toluene mixtures: Performance and mechanisms

TiO₂ nanotube-based (TNT) anodic oxidation methods are widely used for the removal of organic compounds due to their large surface area. However, poor conductivity and limited lifetime constrain its further application. Herein, this study provided a novel strategy to induce reduced TNT surface defects by co-doping boron (B) and manganese (Mn), which promoted its electrocatalytic activity and prolonged the lifetime. The resulting nanoelectrode exhibited projected lifetime of up to 9470.0 h at a current density of 100 mA/cm² and achieved benzene removal efficiency of 89.4 % after 3 h, outperforming undoped and singly doped (B or Mn) nanoelectrodes. Moreover, •OH was identified the primary reactive oxygen species (ROS). Meanwhile, a series of characterization and density functional theory (DFT) theoretical calculations have confirmed that the synergistic co-doping of B and Mn dynamically regulated the reconstruction of defect sites (oxygen vacancies and Ti³⁺) on the anode surface, increasing the density of active sites and thereby enhancing the electrochemical oxidation performance. The B, Mn co-doped reduced TNT nanoelectrode exhibited strong suppression of oxygen evolution reaction (OER) side reactions. This work presents a modification strategy to improve the efficiency and stability of TNT anodes for organic matter removal from aqueous environments, offering new insights into the mechanisms by which elemental doping enhances catalytic performance.