Electrospun Zn-doped TiO2 nanofibers: A highly reusable and stable photocatalyst for the degradation of organic pollutants

Abstract

This study successfully fabricated high-performance Zn-doped TiO₂ nanofibers through a streamlined electrospinning-thermal annealing process. We meticulously optimized synthesis parameters, demonstrating that a 0.02 g zinc acetate concentration and a 750 °C annealing temperature yielded a highly desirable mixed-phase composition of anatase, rutile, and ZnTiO₃, crucial for enhanced photocatalytic activity. These optimized nanofibers exhibited exceptionally high photocatalytic efficiency for degrading both methyl violet and the persistent antibiotic tetracycline under simulated solar light. Comprehensive characterization, including UV–vis, PL, and transient photocurrent analyses, unequivocally confirmed that zinc doping significantly broadened light absorption into the visible spectrum, narrowed the band gap, and remarkably suppressed the recombination of photogenerated electron-hole pairs. Radical trapping and electron spin resonance (ESR) spin-trapping experiments further elucidated that superoxide radical anions were the predominant reactive species driving the degradation. Crucially, the Zn-doped TiO₂ nanofibers displayed high reusability and remarkable long-term stability over multiple cycles, highlighting their robustness. These findings collectively underscore the immense potential of our optimized Zn-doped TiO₂ nanofibers as a highly effective, robust, and sustainable photocatalyst for addressing pressing environmental challenges, particularly in water remediation.