Abstract
Black-colored titanium was obtained by anodic oxidation of a commercially pure grade-1 titanium sheet in a 0.06 M NH4NO3 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 TiO2 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, C16H18N3SCl) solution under ultraviolet irradiation due to the existence of rutile TiO2. 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.
Highlights
Titanium exhibits good corrosion resistance due to the highly protective titanium oxide layer formed on its surface
A black-colored titanium sheet was obtained by the anodic oxidation of commercially pure (CP) grade-1 titanium sheet in a 0.06 M NH4NO3 solution followed by heat treatment at 773 K for 1 h in a low-vacuum furnace
The resulting oxide layer on the titanium substrate was examined by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), glow discharge spectroscopy (GDS), and scanning electron microscopy (SEM)
Summary
Titanium exhibits good corrosion resistance due to the highly protective titanium oxide layer formed on its surface Titanium oxides have another important feature: photocatalytic activity under irradiation by ultraviolet (UV) light [1]. Many studies have been conducted on the fabrication of anodized-titanium layers with enhanced photocatalytic activity on titanium substrates [2]. Ohtsu et al [6] reported that a visible-light-responsive titanium dioxide layer was fabricated by anodizing a titanium sheet in aqueous nitric acid solutions, followed by heat treatment. The photocatalytic activity of the black-colored titanium sheet was examined by observing the decomposition of a methylene blue (MB) solution by irradiation with UV or visible light
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
