Highly porous N-doped TiO2 hollow fibers with internal three-dimensional interconnected nanotubes for photocatalytic hydrogen production

摘要

Fabrication of TiO2 hollow fibers was conducted by atomic layer deposition (ALD) with polysulfone fibers (PSFs) as a template. After the ALD process, the PSFs were removed by heat treatment at 500 degrees C for 1 h to form anatase TiO2 hollow fibers. They were then doped with nitrogen up to similar to 5 at% by treatment in NH3 at 500-600 degrees C. The N-doped TiO2 hollow fibers remained porous and the wall was full of three-dimensional interconnected nanotubes. The X-ray photoelectron spectroscopic analysis indicated that nitrogen was substitutionally doped into oxygen sites of the TiO2 lattice, resulting in band gap narrowing and more absorption in the visible light region. They exhibited significantly improved photocatalytic activity for water splitting due to a lower energy gap, higher reactive surface area (similar to 100 m(2) g(-1)), multiple light reflection, and better charge separation efficiency. The fibers treated at 600 degrees C for 1 h, containing similar to 2.5 at% nitrogen, generated 0.185 mu mol g(-1) of hydrogen after 6 h of irradiation with a 150 W Xe lamp.