Insight into the enhanced electrocatalytic performance of double-layer Ti/Fe2O3/Ce-PbO2 anode for levofloxacin degradation

In this work, a novel double-layer Ti/Fe₂O₃/Ce-PbO₂ (TFCP) electrocatalyst anode was developed on Ti substrate through the consecutive electrodeposition process with Fe₂O₃ and Ce-PbO₂ as the inter-layer and external layer materials, respectively. Compared with Ti/Fe₂O₃ (TF) and Ti/Ce-PbO₂ (TCP), the TFCP endows superior degradation efficiency toward levofloxacin (LFX) up to 92 % within 120 min, while TF and TCP only achieve 68.6 % and 59.7 %, respectively. The improved electrocatalytic performance can be primarily attributed to the introduction of an Fe₂O₃ interlayer beneath of the Ce-PbO₂, which results in lower charge transfer resistance, larger electroactive area, and higher oxygen evolution potential of the TFCP electrode in comparison to TF and TCP electrodes. Radical capture assays demonstrates that ·OH and ·O₂^- are responsible for the degradation of LFX, with ·OH being the primary reactive oxygen species (ROS). Moreover, the possible degradation routes of LFX were plausibly inferred based on the identification of degraded intermediates via liquid chromatography-mass spectrometry (LC-MS) technique together with theoretical calculation with density functional theory (DFT). In conclusion, this work provides a novel guideline for designing novel double layer anode for efficient degradation of refractory organic contaminants.