α-Fe_2O_3纳米颗粒的水热法合成及其光吸收特性

Synthestizing of α-Fe2O3 Nanoparticles by Hydrothermal Method and Its Optical Absorption Properties

以硝酸铁为铁源、以氢氧化钠溶液(或浓氨水)为沉淀剂,在不同条件下,利用水热法合成α-Fe2O3纳米颗粒。用X射线衍射(XRD)、透射电子显微镜(TEM)和紫外可见分光光度计(UV-VIS)对试样进行分析。结果表明:用氢氧化钠溶液作沉淀剂比用浓氨水作沉淀剂更有利于α-Fe2O3颗粒粒径变小,反应温度升高更有利于α-Fe2O3颗粒粒径细化。以氢氧化钠溶液作沉淀剂,在240℃下反应24h,获得粒径小于20nm的α-Fe2O3颗粒。不同条件下水热法合成的α-Fe2O3的紫外可见光吸收光谱表明:随着α-Fe2O3颗粒粒径变小,颗粒对光的屏蔽程度增大;特别是当α-Fe2O3颗粒粒径小于20nm时,它对光完全屏蔽。

α-Fe2O3 nanoparticles was successfully synthesized using iron nitrate as iron source and sodium hydroxide solution （or stronger ammonia water） as precipitant under the different conditions by hydrothermal method. The synthesized samples were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM） and ultraviolet-visible spectroscopy （UV-VIS）. The results showed that sodium hydroxide solution instead of stronger ammonia water as precipitant was in favour of reducing the size of α-Fe2O3 particles. With increasing of the reaction temperature, it was still further beneficial to gain smaller size of α-Fe2O3 particles, α-Fe2O3 particles with less than 20 nm in diameter was prepared using sodium hydroxide solution as precipitant at 240 ℃ for 24 h by hydrothermal method. The analysis of UV-VIS confirmed that the light shield degree of α-Fe2O3 particles was enhanced with the decreasing of size of α-Fe2O3 particles. Especially, the light shield of α-Fe2O3 particles with less than 20 nm in diameter was complete.