Europium doped nanocrystalline titanium dioxide: preparation, phase transformation and photocatalytic properties

Eu3+ (0.25∼10 at.%) doped nanocrystalline titania have been prepared by a special sol–gel method. The XRD results show that the temperature of anatase-to-rutile phase transformation is substantially increased by europium doping and the increase is not proportional to the doped lanthanide content. The highest increase was observed for 1 at.% europium doped samples, which maintained an anatase phase after calcination at 900 °C for 1 h. Together with the increase observed for the phase transformation, the sintering and surface loss associated with the process were significantly reduced as well. Rhodamine B (RB) degradation was used as a probe reaction to determine the effects of the reactivity of the catalyst over a variety of as-prepared materials. The europium doping could bring about remarkable improvement in the photoactivity and the optimum enhancement of photoactivity is seen for 1 at.% europium doped titania. However, the europium doped titania prepared by impregnation only results in diminished activity, showing that the preparation method and distribution of europium play a key role in the photoactivity.