Defects-rich Ru-doped black TiO₂ nanotube arrays for photoelectrochemical levofloxacin degradation coupled with...

As an emerging and promising technology, the bifunctional photoelectrocatalytic (PEC) systems have shown remarkable potential in treating wastewater and producing energy. A central critical challenge in this field is the development of high-performance electrode materials that exhibit superior PEC properties. In this work, the defect-rich Ru-doped black TiO₂ nanotube arrays (Ru-BTNAs) bifunctional electrodes were engineered and utilized in a PEC system, aiming to achieve efficient antibiotics levofloxacin degradation and hydrogen production simultaneously. In-depth characterization characterizations and the Density functional theory (DFT) calculations reveal that the synergistic effect between Ti³⁺-oxygen vacancies (Ovs) defects and Ru doping significantly improves light absorption, accelerates the separation and transmission of photoexcited e^--h⁺ pairs, and optimizes PEC performance. The coupled photocatalytic and electrocatalytic processes enhance the generation of h⁺, ¹O₂, HO^•, and SO₄^•- radicals, which effectively degrade levofloxacin. The abundant Ovs facilitate electron transfer from BTNAs to Ru, accelerating hydrogen evolution reaction (HER) on electron-rich Ru at a low overpotential. This work provides a theoretical framework for designing bifunctional electrode to achieve the energy-efficient hydrogen production from antibiotics-contaminated wastewater.