Ethanol gas sensor based on CoFe2O4 nano-crystallines prepared by hydrothermal method

CoFe2O4 nano-crystallines were prepared by a hydrothermal method at 120-220 degrees C. CoFe2O4 sensors were fabricated from the CoFe2O4 nanocrystallines and their gas sensing properties were investigated. Spinel CoFe2O4 nano-crystallines could be obtained when the pH value was in the range of 8-14, and the morphology of the particles obtained under different conditions was almost spherical. The CoFe2O4 nano-crystallines obtained at a pH of 8-10 exhibited n-type response to gases at low temperatures and p-type response to gases at high temperatures, while CoFe2O4 nano-crystal lines obtained at a pH of 11-14 exhibited p-type response to gases. It was found that the sensor based on the CoFe2O4 nano-crystallines prepared at 180 degrees C for 48 h (pH 8) exhibited good performance, characterized by high responses to dilute C2H5OH and very low responses to petrol, C6H6 and C6H5CH3 when operating at 150 degrees C. If there was no ethanol in the atmosphere, the sensor based on nano-CoFe2O4 (180 degrees C, 48 h, pH 8) could be used to detect triethylamine at 190 degrees C. The sensor is a promising candidate for practical detector for dilute C2H5OH and triethylamine. (c) 2006 Published by Elsevier B.V.