Local Structure of v Dopants in TiO2 Nanoparticles: X-ray Absorption Spectroscopy, Including Ab-Initio and Full Potential Simulations

Doping with transition metals is an effective method to enhance visible-light absorption in TiO2 nanoparticles and to improve the efficiency of many photocatalytic processes under solar radiation. A determination of the incorporation site of the dopant and an understanding of the local bonding arrangement and electronic structure is a necessary step for knowledge-based materials design. In this paper, we report an in-depth X-ray absorption spectroscopy study of V dopants in TiO2 nanoparticles deposited by gas-phase condensation with a local structure similar to anatase, rutile, or intermediate. The combination of K- and L-edge spectra in the pre-edge, edge, and extended energy regions with full potential ab initio spectral simulations shows that V ions occupy substitutional cationic sites in the TiO2 structure, irrespective of whether it is similar to rutile, anatase, or mixed.