Ethanol-sensing characteristics of CdFe2O4 sensor prepared by sol–gel method

CdFe2O4 powder with the structure of spinel-type was fabricated by sol–gel method in the citric acid system. The structure and the crystal phase of the powder were characterized on an X-ray diffractometer (XRD). The shape and the size were analyzed by transmission electron microscope (TEM). Several items were investigated, including effects of calcining temperature on gas-sensing properties, gas response vs. working temperature, selectivity and long-term stability. The results demonstrated that the CdFe2O4 sensor prepared with the powder calcined at 700 °C has a high response, an excellent selectivity, a quick response behavior, and a good stability to ethanol comparing with the CdFe2O4 sensors which dealt with at other temperatures. Its response to 100 ppm ethanol is 55 working at 250 °C.