Nanostructured Titanium Oxynitride Porous Thin Films as Efficient Visible-Active Photocatalysts

✍ Scribed by E. Martínez-Ferrero; Y. Sakatani; C. Boissière; D. Grosso; A. Fuertes; J. Fraxedas; C. Sanchez

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 297 KB
• Volume: 17
• Category: Article
• ISSN: 1616-301X
• DOI: 10.1002/adfm.200700396

✦ Synopsis

Abstract

Nanocrystalline mesoporous N‐doped titania films have been prepared for the first time. The introduction of nitrogen into the anatase structure starts at 500 °C, with N bonding to titanium via oxygen substitution. Increasing the treatment temperature leads to the formation of TiN (TiN~1–~~x~O~x~) and N‐doped rutile showing mixed‐valence Ti states. Microstructural characterization shows that the ordered mesoporosity is maintained until 700 °C, where TiN (TiN~1–~~x~O~x~) begins to form. Optical characterization shows that the discrete introduction of N is able to shift the titania absorption edge. The photocatalytic tests give the best results under visible light excitation for the film nitrided at 500 °C. At this temperature the concentration of nitrogen in the structure is optimal since oxygen vacancies are still not important enough to promote the recombination of the photogenerated electrons and holes.