Trimethylamine sensing properties of CdO–Fe2O3 nano-materials prepared using co-precipitation method in the presence of PEG400

Abstract CdO–Fe2O3 precursors are prepared using co-precipitation method in the presence of PEG400. CdO–Fe2O3 nano-powders are obtained through heating the precursors under different conditions. CdO–Fe2O3 thick film sensors are fabricated using CdO–Fe2O3 nano-materials as sensing materials. The XRD analysis results reveal that CdO–Fe2O3 is mainly composed of CdFe2O4 when the precursor is heated at 700 °C for 2 h and the mole ratio of Cd/Fe is 1:2 in the starting materials. The TEM images show that the average particle sizes increase with heating temperature increasing, the particle sizes are in the range of 15–25 nm when heating temperature is 700 °C (2 h). The influence of the heating duration and heating temperature on the gas-sensing properties of the sensors based on CdO–Fe2O3 nano-materials are investigated. The responses to a few kinds of organic gases, such as (CH3)3N and C2H5OH are studied. It is found that the sensor based on CdO–Fe2O3 nano-material (700 °C, 2 h) exhibits high response to dilute trimethylamine when operating at 230 °C. The responses to 1000 ppm and 0.01 ppm (CH3)3N at 230 °C are 1527 and 2, respectively. The response time and recovery time for 1000 ppm trimethylamine are 70 and 170 s.