Tungsten-Doped Titanium Dioxide in the Rutile Structure: Theoretical Considerations

Tungsten-doped titanium dioxide has the potential to replace conventional carbon black in catalyst support applications. In this paper, structural and electronic properties of W-doped rutile are theoretically studied. Lattice parameters as well as W-W pairing in models for a range of doping are calculated and match well with the experimental results. W doping leads to in-plane expansion and c-axis contraction in the rutile structure. The pairing of tungsten atoms is a Peierls-type distortion, resulting in less cluttering of bands around the Fermi energy. Our computational finding of paired structures as energetically more stable is in agreement with the literature on similar systems. W-doped rutile is conducting at both high and low doping levels; the states involved near the Fermi level are predominantly W(5d).