Abstract: 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.

Key words: sol-emulsify-gel, tetrabutyl titanate, ethyl orthosilicate, sodium dodecyl sulfonate (SDS), α-Fe_2O_3 nanocrystal