Sol–gel iron-doped TiO2nanopowders with photocatalytic activity

Abstract

The aim of the present work was to establish the influence of the Fe-dopant on the structure and photo-catalytic properties of the sol–gel TiO2 nanopowders. The relationship between the synthesis conditionsand the properties of titania nanosized materials, such as thermal stability, phase composition, crys-tallinity, morphology and size of particles was investigated. Undoped, 0.5, 1, 2 and 5 wt% Fe-doped TiO2samples have been prepared and structurally characterized by the XRD method. Lattice parameters, crys-tallite sizes, internal strains, as a measure of structural disorder, were determined. X-ray photoelectronspectroscopy (XPS) and magnetic measurements completed the structural data study. The acceptanceof the dopant by the titania lattice was proved by the XRD measurements and the positive values ofthe magnetic susceptibilities. Its addition is responsible for supplementary defects in the crystalline lat-tice (paramagnetic behaviour). The dopant was present in the low spin state (LS) of Fe3+in the samplewith 0.5 wt% iron concentration and in the high spin state (HS) in the other samples. It influenced thephotocatalytic properties. The photocatalytic activity of the prepared nanopowders has been tested inthe degradation of nitrobenzene from water, as a first mention in literature. The sample with 0.5 wt% Fe dopant concentration thermally treated at 400◦C presented the best photocatalytic activity.