Fabrication of Hollow TiO₂ Nanotubes via a Simple Gas-Phase Process Using In-Flight Coating Followed by Heat Treatment

Abstract

As nanostructured materials with wide applicability, hollow TiO₂ nanotubes (HTNTs) were fabricated for the first time using an “in-flight” coating method. TiO₂ coating layers were deposited on the surface of carbon nanotubes (CNTs) suspended in gas, and the resulting products were then heat-treated. Depending on the annealing process, products with various morphologies, including HTNTs, were produced. Raman spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analyses confirmed the absence of CNTs in the HTNTs. The obtained results will provide valuable information for controlling hollow nanostructured materials for a wide range of applications in fields including photocatalysis, gas sensors, and solar cells.