Preparation and Structure Analysis of α-Fe_2O_3 Nanocrystalline in 2-Methoxyethanol System

The nanocrystal α-Fe2O3 with an average size of about 30nm was prepared by a sol-emulsify-gel method in the iron nitrate and 2-methoxyethanol system. The powders were characterized by TEM, XRD and the xerogel primary powders thermal stability was studied by TG-DTA. The gelation time was reduced greatly by adding tetrabutyl titanate. When tetraethyl orthosilicate instead of tetrabutyl titanate, the gelation time can be much longer. γ-Fe2O3 with spinel structure appeared as the main phase in the calcinated powder and the average particle size was about 10nm. A new idea to improve the gas sensitivity and stability of γ-Fe2O3 gas-sensitive materials was provided. The results show that the introduction of surfactant(SDS) is helpful to form pure crystal phase α-Fe2O3.