%0 Journal Article
%T Characterization of Surface Oxide Layers on Black-Colored Titanium
%A Michio Kaneko
%A Kiyonori Tokuno
%A Kazuo Yamagishi
%A Takao Wada
%A Tsuyoshi Hasegawa
%J Journal of Surface Engineered Materials and Advanced Technology
%P 71-82
%@ 2161-489X
%D 2018
%I Scientific Research Publishing
%R 10.4236/jsemat.2018.84007
%X Black-colored titanium was obtained by anodic oxidation of a commercially pure grade-1 titanium sheet in a 0.06 M NH<sub>4</sub>NO<sub>3</sub> solution, followed by heat treatment at 773 K for 1 h in a vacuum furnace. The resulting oxide layer on the titanium substrate was examined by X-ray photoelectron spectroscopy, X-ray diffraction, glow discharge spectroscopy, and scanning electron microscopy. It was found that the oxide layer on the black-colored titanium sheet was several micrometers thick and mainly consisted of rutile TiO<sub>2</sub> exhibiting a sponge like nanoporous structure. It is considered that the black-colored appearance of the titanium sheet is due to the sponge like nanoporous structure of the oxide layer absorbing the incident light. The photocatalytic activity of the black-colored titanium sheet was examined by observing the decomposition of a methylene blue (MB, C<sub>16</sub>H<sub>18</sub>N<sub>3</sub>SCl) solution under ultraviolet irradiation due to the existence of rutile TiO<sub>2</sub>. The sheet also exhibited photocatalytic activity under visible light irradiation. It is believed that the photocatalytic response upon irradiation with white light is due to carbon doping of the titanium oxide layer on the titanium substrate.
%K Titanium
%K Titanium Oxide
%K Titanium Dioxide
%K Rutile
%K Photocatalyst
%K Visible Light Response
%K Nanoporous Structure
%U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=87147