Sulfide-sensing characteristics of MFe2O4 (M = Zn, Cd, Mg and Cu) thick film prepared by co-precipitation method

This paper reports the gas-sensing properties to dilute volatile sulfides such as H2S, CH3SH and (CH3)2S of MFe2O4 (M=Zn, Cd, Mg and Cu) thick film sensors. The raw powders of MFe2O4 were prepared by co-precipitation method. Effects of calcining temperature on gas-sensing properties, sensitivity-operating temperature, and sensitivity-gas concentration were investigated. The crystal structure and surface morphology were examined by means of X-ray diffraction (XRD) and SEM, respectively. The results demonstrated that the CdFe2O4 sensor prepared by using the powder calcined at 700 °C showed high sensitivity as well as good selectivity to dilute CH3SH at 250 °C. Especially, the CdFe2O4 sensor showed the sensitivity as high as 2 even to 0.01 ppm CH3SH.