Neodymium ion dopant effects on the phase transformation in sol-gel derived titania nanostructures

Doped and undoped nanostructured titanium dioxide was synthesized via a sol-gel method under varying conditions to determine the effects of neodymium ion doping on the titania lattice. Specifically, the effects of doping on the anatase to rutile phase transformation were studied. Samples were analyzed by a variety of techniques, including X-ray diffraction, Rutherford back-scattering spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry to investigate the thermodynamic and structural effects of dopant addition. Analysis of the anatase to rutile phase transformation in TiO2 showed a maximum increase in activation energy for 0.1 mol% Nd3+ doped TiO2 with no further response at higher dopant concentrations. This was supported by structural analyses, which showed distortion only along the c-axis of anatase TiO2 with a maximal distortion at 0.1 mol% Nd3+ and no further response at higher concentration. This is due to a combination of interstitial and substitutional accommodation of the dopant ions. (C) 2004 Elsevier B.V. All rights reserved.