Electrochemical oxidation of rhodamine B by PbO₂/Sb-SnO₂/TiO₂ nanotube arrays electrode

A PbO₂/Sb-SnO₂/TiO₂ nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated. Field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) results showed that the PbO₂ coating was composed of an α-PbO₂ inner layer and a β-PbO₂ outer layer. Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h. Rhodamine B (RhB) was employed as a model pollutant to analyze the electrocatalytic activity of the electrode. The effects of initial RhB concentration, current density, initial pH, temperature, and chloride ion concentration on the electrochemical oxidation were investigated in detail. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) results suggested that the concentration of leached Pb²⁺ in the electrolyte during the electrocatalytic oxidation process can be neglected. Finally, the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry (SPME-GC-MS). The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution.