Influence of Carbon Nanotubes on Photocatalytic Activities of Titanium Dioxide Nanocomposite Powders

Abstract

This research aims to produce TiO2-based composite powder by growing of carbon nanotubes (CNTs) on the surface of micron-sized TiO2 particles using a chemical vapor deposition (CVD) technique. This nanocomposite powder will be further used as feedstock powder to build up as a coating using a thermal spray technique. This coating is expected to have better photocatalytic efficiency over that of pure TiO2 coating. For composite powder preparation, rutile-phase of TiO2 powder with particle size in a range of 25 – 45 µm was used as a starting powder. The powder was placed in a CVD apparatus under ethanol atmosphere as a carbon source. The best CNTs growing condition was found to be 650°C for 60 min. The starting powder and as-synthesized composite powders were characterized by scanning electron microscopy, energy dispersive spectrum, Raman spectroscopy and UV-vis spectroscopy. The results showed that CNTs were successfully grown in-situ on the surface of TiO2 particles. The photocatalytic activities under visible-light were examined based on a degradation of methylene blue. The degradation efficiency of the TiO2/CNTs composite powder was found to be higher than that of pure TiO2. It is expected that the TiO2/CNTs nanocomposite powder could be further used to fabricate various of nanocomposite products.