Phase transformation and crystal growth behaviors of La 3+/Ce 3+-doped TiO 2–20 wt% SnO 2 gels

Abstract

The transformation behaviors of La 3+/Ce 3+-doped TiO 2–SnO 2 gels were studied by using differential thermal analysis and X-ray diffraction methods so as to improve the phase transformation and decrease the granularity of crystals. Experimental results show that, anatase, rutile and SnO 2 nanocrystals can exist in the sintering products by varying La 3+/Ce 3+ contents and sintering temperatures. 0.8–1.1 wt% of La 2O 3 or CeO 2 doping greatly depresses the growth of anatase and rutile crystals, obtaining nanosized crystals when sintered up to 600 °C for 2 h. With La 3+/Ce 3+-doping and increasing their contents, the transformations of gel to anatase and anatase to rutile, as well as the growth of anatase and rutile crystals can be depressed, while the transformation temperature of anatase to rutile receives much less affect. Moreover, the La 3+-doping has stronger effects on them than Ce 3+ doping, but has a weaker inhibiting effect on precipitation and growth of SnO 2 crystals.