摘要
以TiCl4、Cr(NO3)3.9H2O为原料采用共沉淀法制备了掺杂不同量Cr3+离子的纳米TiO2,通过XRD、DSC、TG-DTG、FT-IR和UV-Vis等分析手段对样品的晶体类型、光谱吸收特征进行了表征,并研究了TiO2在锐钛矿型和金红石型之间的晶型转变过程。结果表明Cr3+离子的掺入可促进TiO2的结构相变,显著降低相变温度,延缓了结晶水的排出。少量Cr3+离子掺入TiO2后,主要以替代的方式占据TiO2晶格中Ti4+的位置,并在TiO2禁带中产生掺杂能级,提高了可见波段的光吸收,使原来位于380nm的吸收边向长波方向移动,并且在480nm产生了新的吸收边,实现了与太阳光谱的匹配。当掺杂量达到33%时,Cr3+可能以Cr2O3的形式与基体TiO2形成新物质Cr2TiO5。
Cr-doped TiO2 nano-powders were synthesized by co-precipitation method from TiCl4 and Cr（NO3）3 · 9H2O. The crystal types, the feature of absorption spectrum of TiO2, and the polymorphic phase transition from anatase to rutile was examined by XRD, DSC, TG-DTG, FT-IR and UV-Vis. The results indicate that the doped Cr^3＋ can effectively expedite the phase transformation of TiO2, reduce the transition temperature re markably, and delay the releasing of crystalloid water. When the quantity of Cr^3＋ ions was small, Cr^3＋ ions can mainly penetrate into the lattice of TiO2 and substitute the Ti^4＋ ions of TiO2. And then a doping energy level emerges among the gap of TiO2, which help to increase the visible light absorption of TiO2. The original absorption edge （about 380nm） of TiO2 moves to the longer wave, and new absorption edge （about 480nm） appears to match with solar spectrum. When the molar ratio of Cr^3＋ to TiO2 was up to 33 %, Cr^3＋ ions exist with TiO2 in the form of Cr2O3 and combine to form a new substance： Cr2TiO5.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2005年第9期1404-1408,共5页
Journal of Functional Materials
