| AVS 58th Annual International Symposium and Exhibition | |
| Energy Frontiers Focus Topic | Wednesday Sessions |
| Session EN2+TF-WeA |
| Session: | Thin Films for Solar Fuels |
| Presenter: | Luca Lozzi, University of L'Aquila, Italy |
| Authors: | D. Di Camillo, University of L'Aquila, Italy F. Ruggieri, University of L'Aquila, Italy L. Lozzi, University of L'Aquila, Italy S. Santucci, University of L'Aquila, Italy |
| Correspondent: | Click to Email |
Titanium dioxide (TiO2), thanks to its interesting properties as nontoxicity, low cost and high chemical stability, has been extensively investigated for several application in which, following light absorption, the generated charges can be usefully applied, as for photovoltaic applications or for photocatalytic devices. However, due to the wide intrinsic energy gap of TiO2 (between 3.0 and 3.2 eV, depending on the crystalline structure), only a small fraction of the solar spectrum can be used to promote the light absorption [6]. In the photocatalytic devices one of the most important goal of the recent research is to be able to prepare photocatalyst which can be active by absorbing the visible light, in order to increase the application of TiO2-based system in poor regions (where it could be difficult to use UV light sources) or to reduce the application cost . In order to increase the fraction of the solar spectrum that can be absorbed, different approaches have been used, mainly by doping TiO2 with metals or anions.
One of the most studied doping is using nitrogen. TiO2 doped with nitrogen atoms can be prepared in different ways, as powders, as thin films by sol-gel or reactive sputtering.
In this paper we will show the photocatalytic results obtained depositing TiO2 N-doped nanofibers (NF) prepared by means of electrospinning (ES) and near-field electrospinning (NF-ES) techniques for the photo-degradation of methylene blue (MB) in water under visible light. The ES preparation technique allows a quick deposition of fibers on wide surfaces using a cost-effective system. Instead NF-ES method allows the growth of a well ordered NF net, with a spacing lower then few microns.
The NFs were deposited using different deposition and post-deposition parameters (solution composition, annealing temperature and atmosphere) and have been characterized by using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD) and Secondary Electron Microscopy (SEM). The photocatalytic properties have been studied recording the variation of the optical absorption of MB when the sample is illuminated by an halogen lamp (visible spectrum).
The annealing process determines a partial loss of nitrogen and the formation of the Anatase crystalline phase. The TiO2 N-doped NFs have shown interesting degradation properties, which are much better than those observed when TiO2 NFs are used.