Influence of Fe and Al doping in the stabilization of the anatase phase in TiO_2 nanoparticles

Abstract

Anatase TiO_2 nanoparticles doped with Al or Fe have been synthesized via a modified Pechini method which allows to reach high control in size and composition. Microstructural analysis onfirms the good crystallinity of the doped anatase nanoparticles with average sizes around 5 nm and dopant cationic concentrations up to 30 %. Anatase to rutile transition (ART) has been thermally driven and analyzed as a function of the doping. Thermo-diffraction measurements indicate that the phase transition can be either promoted or inhibited by Fe or Al doping, respectively. The influence of Al and Fe doping in the phase transition has been discussed by means of Raman spectroscopy, Photoluminescence and X-ray Photoelectron spectroscopy, with special attention paid to the role played by Ti^(3+) at the surface. Anatase phase has been stabilized up to temperatures above 900 ºC by appropriate Al doping