Abstract
TiO2 nanosheets were modified by two different procedures (volume and surface modification) with 0.5 wt % of (57)Fe toward Ti. In the case of volume modification, the (57)Fe (in the form of (57)Fe(NO3)(3) · n H2O solution) was added at the beginning of preparation of TiO2 nanosheets while the surface modified sample was prepared from the aqueous suspension of undoped TiO2 nanosheets annealed at 800 °C and solution of (57)Fe(NO3)(3) · n H2O via impregnation method.
The volume modified sample was later annealed at 650, 800, and 950 °C; no further annealing was done on the surface modified sample. Both types of prepared materials were characterized by electron microscopy, X-ray powder diffraction, surface and porosity measurements, thermal analysis, FTIR and Raman spectroscopies, and Mossbauer spectroscopy.
Photocatalytic activity was characterized from the results of 4-chlorophenol (4-CP) decomposition. The surface modified sample exhibited highly effective photocatalytic decomposition of a model pollutant under UV irradiation.
On the other hand, the volume modification proved to suppress photocatalytic activity under UV. The visible light activity of 4-CP decomposition was negligible for both volume and surface modified samples.
Mossbauer spectroscopy measurements confirmed the presence of iron atoms in the TiO2 structure. The surroundings of the iron atoms exhibit a structure close to that of mixed oxides (Fe(1-x)Ti(2-x)O5 and Fe(2-x)Ti(x)O3) in solid solution.