Influence of N-Doping on the Structure and Electronic Properties of Titania Nanoparticle Photocatalysts

Abstract

N-containing TiO(2)-based nanostructured materials (average particle size approximately 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 ([6])Ti with some ([5])Ti, and there is no evidence for ([4])Ti. 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 Ti(3+) states. We discuss the influence of N-doping on titania nanoparticles and their structure, electronics and photocatalytic activity.

Exploring the incorporation of nitrogen in titanium and its influence on the electrochemical corrosion resistance in acidic media

“…These properties could be used to produce hydrogen directly from solar light or electrolysis of water into its principal components. One of the most important issues is whether the nitrogen is incorporated by the titanium lattice substitutionally or interstitially [16] modifying its performance as electrode drastically as well as outstanding oxidation behaviors and corrosion resistance [17,18]. Although there is a lot of literature [19][20][21][22] no consensus among the reports on the state of doped nitrogen in N-TiO 2 has been established.…”

Structure of epitaxial (Fe,N) codoped rutile TiO2thin films by x-ray absorption

“…Previous studies on N:TiO 2 nanoparticles found a loss of fine structure in the O K-edge, which was attributed to the presence of a substantial fraction of oxygen vacancies. 17 The prominent fine structure in Fig. 4(a) implies that the concentration of oxygen vacancies formed during film synthesis is much less than in previous nanoparticle work 17 and is below the detection limit of O K-edge XANES.…”

“…17 The prominent fine structure in Fig. 4(a) implies that the concentration of oxygen vacancies formed during film synthesis is much less than in previous nanoparticle work 17 and is below the detection limit of O K-edge XANES. The O K-edge of TiO 2 is understood to consist of two strong pre-edge peaks arising from transitions from O 1s to hybridized Ti 3d-O 2p orbitals; the Ti 3d orbitals are further split into t 2g and e g components.…”

“…Previous XAS studies of N-doped TiO 2 have focused on x-ray absorption near edge spectroscopy (XANES) of the O K-edge, Ti K-edge, Ti L-edge, and in some cases the N K-edge of N-doped anatase powders and nanoparticles. For example, Stewart et al 17 found evidence of substantial O vacancy formation from both the O K-edge XANES and the pre-edge features of the Ti K-edge XANES. Changes to the electronic structure and atomic ordering were attributed to these vacancies and did not directly correlate with the small amount of N detected.…”

Probing Long‐Lived Plasmonic‐Generated Charges in TiO2/Au by High‐Resolution X‐ray Absorption Spectroscopy

“…[11] On the other hand, investigation of nanosized TiO 2 indicated that A 2 is particularly sensitive to crystallinity [12] and NP size [13] so that A 2 intensity can be correlated to low-coordinated Ti sites at the surface.…”