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Nanostructured Titanium Oxynitride Porous Thin Films as Efficient Visible‐Active Photocatalysts
Author(s) -
MartínezFerrero E.,
Sakatani Y.,
Boissière C.,
Grosso D.,
Fuertes A.,
Fraxedas J.,
Sanchez C.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200700396
Subject(s) - materials science , tin , rutile , anatase , nanocrystalline material , photocatalysis , titanium , titanium nitride , mesoporous material , doping , absorption edge , chemical engineering , nitriding , nanotechnology , nitride , optoelectronics , metallurgy , band gap , layer (electronics) , biochemistry , chemistry , engineering , catalysis
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.