Influence of N-doping on the structure and electronic properties of titania nanoparticle photocatalysts

摘要

N-containing TiO2-based nanostructured materials ( average particle size similar to 10 nm) with an anatase-type structure were investigated using oxygen (O) K-edge and titanium (Ti) K- and L-edge X-ray absorption near-edge spectroscopy (XANES). The Ti K pre-edge features indicate that samples predominantly contain Ti-[6] with some Ti-[5], and there is no evidence for Ti-[4]. We observed that those samples with a larger fraction of Ti in a fivefold coordination, that is, with a significant number of oxygen vacancies, also present a modified Ti environment at the medium-range scale. The presence of these defects drastically modifies the electronic structure of the conduction band, as evidenced by the O K XANES spectra, but does not result in the presence of reduced Ti3+ states. We discuss the influence of N-doping on titania nanoparticles and their structure, electronics and photocatalytic activity.