Preparation and gas-sensing properties of CuFe2O4 at reduced temperature

Sol-gel and co-precipitation were used for preparation of copper ferrite. Pure CuFe2O4 was not obtained until 800 degrees C by a sol-gel process, which might be due to the loose contact between copper and iron atoms and the possible low diffusion rate. However, nanocrystalline CuFe2O4 was prepared by a co-precipitation method. The tetragonal CuFe2O4 phase was formed at 90 degrees C. The decomposition of amorphous hydroxides in the dried precipitate continued until 450 degrees C, according to a TG-DTA analysis. Conductance- temperature measurements of the sensor made of CuFe2O4 indirectly indicated that the amount of absorbed oxygen was small, as reflected by the relatively low response. The CuFe2O4 sensors showed a good response to alcohol, which is promising for further development of this type of sensor. The difference in response for various tested gases might be attributed to absorption of reducing gases and reaction between these gases and the absorbed oxygen. It is supposed that the gas-sensing properties of this material might be improved by the addition of catalysts. (C) 2000 Elsevier Science S.A. All rights reserved.