Defects-rich Ru-doped black TiO2 nanotube arrays for photoelectrochemical levofloxacin degradation coupled with simultaneous cathodic H2 production

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 center dot, and SO4 center dot- 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.