Synthesis and properties of Sn1−xFexO2 nanoparticles obtained by a proteic sol–gel method

Abstract

Iron-doped SnO2 nanoparticles with chemical formula Sn1−xFexO2−y (x = 0.02, 0.05 and 0.10 at%) were successfully produced by a proteic sol–gel method. Thermogravimetric analysis and differential scanning calorimetry were performed to investigate the thermal behavior of the precursor powders as well as to select the appropriate calcination temperatures for oxide formation. X-ray absorption near-edge spectroscopy studies were carried out to determine the valence state of the transition metal used as dopant. Structural, morphological, and optical properties of the synthesized materials were studied by X-ray diffraction, Mossbauer spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, and ultraviolet-visible spectroscopy. The results confirmed the formation of nanometric spherical particles of single-phased SnO2 with rutile-type tetragonal structure. Iron doping was accomplished in the form of Fe3+ substituting for Sn4+ in the SnO2 matrix, with the creation of oxygen vacancies to achieve charge balance. Band gaps of SnO2 were found to be unaffected by the introduction of iron.