Structure and composition of electrospun titania nanofibres doped with Eu†

Electrospinning technique was used to prepare the nanofibres of pure and Europium (Eu)-doped titania with Eu content of 3–10%mol. The solution was electrospun in air at room temperature. The obtained fibrousmats were thermally treated at 500 or 1000 ◦C. Morphology and phase analyses of the resulting fibrous ceramic mats were carried out by using SEM and X-ray diffraction (XRD), while the surface chemical composition was investigated by XPS. Annealed mats consisted of randomly oriented fibres with fairly uniform and nanometric diameter, dependent on the doping level. The main titania phase in the samples, heated at 500 ◦C, was anatase, whereas rutile phase with small traces of Eu2Ti2O7 were identified in the samples calcined at 1000 ◦C. From the XPS analysis, it was determined that all the samples were composed of Ti4+ and Eu3+ species. XPS quantification of annealed samples revealed a surface enrichment with Eu. XPS depth profiles demonstrated that the chemical composition of the samples was constant. Moreover, it was observed that the Ti4+ reduction, induced by ion sputtering, decreased in the samples with higher concentration of Eu dopant.