10.1021/jp064893e.s001
Masaaki Kitano
Masaaki
Kitano
Keisho Funatsu
Keisho
Funatsu
Masaya Matsuoka
Masaya
Matsuoka
Michio Ueshima
Michio
Ueshima
Masakazu Anpo
Masakazu
Anpo
Preparation of Nitrogen-Substituted TiO<sub>2</sub> Thin Film Photocatalysts by the Radio Frequency
Magnetron Sputtering Deposition Method and Their Photocatalytic Reactivity under Visible
Light Irradiation<sup>†</sup>
American Chemical Society
2006
TiO 2 lattice
radio frequency magnetron
XPS
light irradiation
lattice O atoms
550 nm
XRD
UV
scanning electron microscopy
SEM
concentration
Radio Frequency Magnetron Sputtering Deposition Method
film photocatalysts
TiO 2
2006-12-21 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Preparation_of_Nitrogen_Substituted_TiO_sub_2_sub_Thin_Film_Photocatalysts_by_the_Radio_Frequency_Magnetron_Sputtering_Deposition_Method_and_Their_Photocatalytic_Reactivity_under_Visible_Light_Irradiation_sup_sup_/3040045
Nitrogen-substituted TiO<sub>2</sub> (N−TiO<sub>2</sub>) thin film photocatalysts have been prepared by a radio frequency
magnetron sputtering (RF-MS) deposition method using a N<sub>2</sub>/Ar mixture sputtering gas. The effect of the
concentration of substituted nitrogen on the characteristics of the N−TiO<sub>2</sub> thin films was investigated by
UV−vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and
scanning electron microscopy (SEM) analyses. The absorption band of the N−TiO<sub>2</sub> thin film was found to
shift smoothly to visible light regions up to 550 nm, its extent depending on the concentration of nitrogen
substituted within the TiO<sub>2</sub> lattice in a range of 2.0−16.5%. The N−TiO<sub>2</sub> thin film photocatalyst with a
nitrogen concentration of 6.0% exhibited the highest reactivity for the photocatalytic oxidation of 2-propanol
diluted in water even under visible (λ ≥ 450 nm) or solar light irradiation. Moreover, N−TiO<sub>2</sub> thin film
photocatalysts prepared on conducting glass electrodes showed anodic photocurrents attributed to the
photooxidation of water under visible light, its extent depending on wavelengths up to 550 nm. The absorbed
photon to current conversion efficiencies reached 25.2% and 22.4% under UV (λ = 360 nm) and visible light
(λ = 420 nm), respectively. UV−vis and photoelectrochemical investigations also confirmed that these thin
films remain thermodynamically and mechanically stable even under heat treatment at 673 K. In addition,
XPS and XRD studies revealed that a significantly high substitution of the lattice O atoms of the TiO<sub>2</sub> with
the N atoms plays a crucial role in the band gap narrowing of the TiO<sub>2</sub> thin films, enabling them to absorb
and operate under visible light irradiation as a highly reactive, effective photocatalyst.