Preparation and characterization of a novel blue-TiO2/PbO2-carbon nanotube electrode and its application for degradation of phenol

Abstract

In this study, we fabricated a blue-TiO₂/PbO₂-carbon nanotube (CNT) electrode in which blue TiO₂ nanotube arrays (blue-TNA) served as the substrate for PbO₂-CNT eletrodeposition. Scanning electron microscope (SEM) showed compact surface structure of the electrode. The β-PbO₂ crystal structure was detected by X-ray diffraction (XRD). The distribution of Pb, O, C, and Na elements on the electrode surface have been confirmed by X-ray photoelectron spectroscopy (XPS). Blue-TiO₂/PbO₂-CNT electrode had higher response current (213.12 mA), larger active surface area and lower charge transfer resistance (2.22 Ω/cm²) than conventional TiO₂/PbO₂-CNT electrode. The influences of current density, initial phenol concentration, initial solution pH, and Na₂SO₄ concentration on the electrochemical oxidation of phenol have been analyzed. The results showed that the 100 mg/L phenol could be destroyed completely after 210 min, and chemical oxygen demand (COD) removal rate was 89.3% within 240 min. Additionally, the electrode showed long actual lifetime (5468.80 hr) and low energy consumption (0.08 kWh/gCOD). A phenol degradation mechanism was proposed by analyzing the intermediate products with high-performance liquid chromatography-mass spectrometry (HPLC-MS). Importantly, the blue-TiO₂/PbO₂-CNT electrode exhibited superior stability and high degradation efficiency after 15 times reuse, demonstrating its promising application potential on phenol-containing wastewater treatment.

Keywords: Blue-TiO(2); Electrochemical oxidation; Electrodeposition; Phenol.