Photocatalytically active TiO2 microtubes assembled with radially aligned nanowires

Abstract

Hollow nanoarchitectures enhance mass transport whilst retaining the merits arising from these unique nanostructures, which are thus ideal structures for an efficient photocatalyst. In this study, polyester fibers were utilized to construct TiO₂ hollow microtubes with radially aligned nanowires, through multi-steps of sol–gel, solution precipitation, and calcination. The TiO₂ microtubes are ca. 10 μm in diameter, assembled with radially aligned nanowires that are ca. 40 nm in diameter and 1 μm in length. The microtubes as a whole consisted of anatase, rutile and brookite, which exhibit a band gap of 3.05 eV and a specific surface area of 36.0 m² g⁻¹. When utilized to assist photodegradation of rhodamine B in water under UV light illumination, the microtubes exhibited an efficiency much higher than that of sol–gel TiO₂ nanoparticles, and similar to that of commercial P25 TiO₂ nanoparticles, which could be attributed to the abundant surface hydroxyl groups and the nanowire-assembled hollow structure. Also, because of the easy recovery of the photocatalyst from the slurry system, the TiO₂ microtubes developed herein are good candidates for effective photodegradation of organic pollutants in water.