SiO2包覆Fe2O3纳米粒子的制备和性能

Synthesis and properties of Ve_2O_3 nanoparticles coated with SiO_2

在近球形α-Fe_2O_3颗粒的悬浮液中,以正硅酸乙酯(TEOS)为硅源,氨水和尿素为催化剂,合成了Fe_2O_3-SiO_2核一壳粒子.应用TEM、XRD对Fe_2O_3-SiO_2核-壳粒子结构进行了测定.研究了TEOS、氨水的浓度对核-壳粒子结构的影响.UV-Vis吸收光谱表明,SiO_2壳层消除了Fe_2O_3纳米粒子的表面悬挂键,产生增强的激子发射,使得核-壳粒子的吸收峰发生蓝移.根据带边吸收峰的波长计算出核-壳粒子中Fe_2O_3的禁带宽度为2.25 eV.

The Fe2O3-SiO2 core-shell particles were synthesized through the hydrolysis of TEOS in the pseudo-spherical α-Fe2O3 suspensions catalyzed by ammonia and urea. The TEM and XRD were used to character the structure of these composite particles. The effect of concentration of TEOS and ammonia on the composite particles＇ structure was also investigated. The UV-Vis spectra of Fe2O3-SiO2 core-shell particles showed the blue-shift absorption compared with that of the Fe2O3 cores, it might be caused by the elimination of suspended bonds at the surfaces of the Fe2O3 cores and the intensification of excitonic emission. The band gap of the Fe2O3 phase in the composite particles was estimated to be about 2.25 eV.