Τίτλος:
EPR, spectroscopic and photocatalytic properties of N-modified TiO 2 prepared by different annealing and water-rinsing processes
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
Samples of TiO 2, calcined at 350 °C, 400 °C, 450 °C and 500 °C, have been prepared without and with water rinsing. The crystallite sizes were determined to be below 32 nm for all types of samples. Temperature dependence of magnetic resonance spectra of the obtained samples has been investigated. The electron paramagnetic resonance (EPR) spectra of free radicals were recorded for all samples, non-rinsed and water-rinsed, centered between g eff = 2.0027(3) and g eff = 2.0032(3) with linewidths ΔH pp = 5(1) G and ΔH pp = 8(1) G. The temperature dependence of the EPR integrated intensities has shown the presence of different relaxation processes operating in high temperature range, which could have arisen due to different concentrations of conducting electrons. For the water-rinsed sample annealed at 400 °C the ferromagnetic resonance (FMR) spectrum of magnetic agglomerates was recorded. Very intense reorientation processes of a correlated spin system have been observed in different temperature ranges. The EPR spectra of trivalent titanium ions were registered in all samples. The number of oxygen vacancies could have increased, possibly involving complexes and agglomerates containing trivalent titanium ions. © 2012 Elsevier B.V. All rights reserved.
Συγγραφείς:
Guskos, N.
Guskos, A.
Zolnierkiewicz, G.
Typek, J.
Berczynski, P.
Dolat, D.
Grzmil, B.
Ohtani, B.
Morawski, A.W.
Περιοδικό:
Materials Chemistry and Physics
Λέξεις-κλειδιά:
Conducting electrons; EPR spectra; High temperature range; Integrated intensities; Magnetic agglomerates; Magnetic resonance spectra; Photocatalytic property; Reorientation process; Spin systems; Temperature dependence; Temperature range; TiO; Titanium ion; Water rinsing, Agglomeration; Calcination; Electron resonance; Ferromagnetic resonance; Fourier transform infrared spectroscopy; Free radicals; Magnetic resonance spectroscopy; Nanostructures; Paramagnetic resonance; Paramagnetism; Photocatalysis; Photoemission; Temperature distribution; Titanium; Titanium dioxide, Electron spin resonance spectroscopy
DOI:
10.1016/j.matchemphys.2012.07.062
