Facile synthesis of CoFe2O4 nanoparticles and their gas sensing properties

In recent years, the use of metal ferrites as sensing materials has aroused more and more interest. However, there is a challenge in the use of cobalt ferrite as ethanol sensor with good gas-sensing properties. In this paper, CoFe2O4 was successfully synthesized by using a facile route. The as-synthesized CoFe2O4 exhibited n-type gas-sensing behavior that the resistance decreases in a reducing gas atmosphere. When applied as sensing materials, CoFe2O4 sensors show good sensitivity to ethanol. At 200 °C working temperature, the response value of CoFe2O4 calcined at 400 °C (CFO-400) sensor to 100 ppm ethanol gas is 110, which is much higher than that of CoFe2O4 ethanol sensor in other studies. Additionally, the CFO-400 sensor shows satisfactory repeatability and stability, as well as high selectivity to ethanol detection compared to other gases. The possible sensing mechanism is investigated in this paper. This work not only displays a facile way to synthesize CoFe2O4, but also provides potential material for gas sensors in future applications.