TiO_2对α-Fe_2O_3纳米微粒拉曼散射效应的影响

The Effect of TiO_2 on Raman Scattering of Nano-particles α-Fe_2O_3

选取α Fe2O3和TiO2研究一种氧化物对另一种氧化物的拉曼散射效应。采用Sol gel方法制备纳米α Fe2O3/TiO2复合微粒,α Fe2O3粒径及含量分别为20nm、150nm和3%、6%、12%。制备过程中调节水解时的pH值和热处理温度,得到掺杂α Fe2O3粒子的不同晶型的TiO2纳米颗粒。Raman测量结果显示,α Fe2O3粒径越小、含量越高,TiO2对其散射效应的影响越大。不同的TiO2晶型对α Fe2O3纳米粒子的拉曼增强效应也不同。锐钛矿型及金红石型TiO2对α Fe2O3有一定的拉曼增强作用,当水解pH值较小时,得到板钛矿型TiO2,由于部分板钛矿型TiO2振动声子模的峰位与α Fe2O3的重叠,所以尚难观察它对α Fe2O3的拉曼增强效应。

TiO_2 and α-Fe_2O_3 were selected to study the effect of Raman scattering of one oxide on the other. The mixed nano-particles TiO_2 and α-Fe_2O_3 were prepared by the sol-gel method. The different mixed nano-particles of α-Fe_2O_3/TiO_2 could be obtained with the variation of α-Fe_2O_3 particle size,the content of α-Fe_2O_3,hydrolytic pH and the annealing temperature. The result shows that the smaller the particle size of α-Fe_2O_3 is and the more the content of α-Fe_2O_3 is,the more powerful Raman effect of TiO_2 on α-Fe_2O_3 is. Different forms of TiO_2 reveal different effect on the Raman scattering of α-Fe_2O_3 nano-particles. The anatase and rutile could enhance the Raman scattering signal of α-Fe_2O_3. It was difficult for brookite to observe the Raman scattering effect on α-Fe_2O_3 because the positions of some of its vibrational phonon modes overlapped that of α-Fe_2O_3.