La^(3+)、Ce^(4+)掺杂对纳米TiO_2-Fe_2O_3凝胶相变过程的影响

Effects of La^(3+) and Ce^(4+) Doping on Phase Transformation of Nano-meter TiO_2-Fe_2O_3 Gels

采用sol-gel法制备了掺杂La3+、Ce4+的TiO2-10wt%Fe2O3复合粉体,利用TG-DTA和XRD分析对凝胶的相变过程进行了表征。结果表明:TiO2-10wt%Fe2O3凝胶在450℃发生非晶态向锐钛矿相的转变,而在500℃煅烧2 h后未发现锐钛矿相向金红石相转变;随La3+、Ce4+掺杂量的增加,锐钛矿晶粒呈现细化→长大的趋势;随La3+掺杂量的增加,对Fe2O3微晶的生成作用呈现促进→抑制的趋势,而对Fe3O4微晶的生成呈现抑制→促进的趋势;随Ce4+掺杂量的增加,对Fe2O3微晶的生成作用随掺杂量的增加呈促进→抑制→促进的趋势,而对Fe3O4微晶的生成呈现抑制→促进的趋势;La3+、Ce4+掺杂对TiO2相变过程有重要影响。

Nano-powders doped La3＋ and Ce4＋ were fabricated by sol-gel process. The effects of La3＋ and Ce4＋ doping on the phase transformation ofnano-meter TiO2-Fe2O3 gels was investigated by TG-DTA and XRD technique. The results show that the transformation temperature of gels to anatase of TiO2-10wt%Fe2O3 occurs at 450℃, however, rutile phase does not appear at 500℃ for 2 h. With the increase of La3＋ and Ce4＋-doping content, the granularity of anatase presents the trend of refined→grown. With the increase of La3＋-doping content, the microlite of Fe203 is improved→depressed and that of Fe3O4 is depressed→improved. With the increase of Ce4＋-doping content, the microlite of Fe203 is improved→depressed→improved and that of Fe304 is depressed→improved. It can be known that the doping of La3＋ and Ce4＋ has important effects on the phase transformation behavior.