Development of an array of polymer/MnO2/Fe2O3 mixtures for use in gas sensing applications

This paper investigates an array of thick-films gas sensors made from polymer, iron oxide and manganese oxide. The films were printed onto glass substrates with silver electrodes. The effects of different gas vapours on the devices at room temperature were investigated. The response of the sensors was defined as, ΔR = ((Rgas − Rair)/Rair) × 100 and was seen to increase with increasing gas vapour concentration. It was observed that various film compositions showed a higher response to propanol and toluene than that to chloroform, ethanol and hexane. The response of the sensors to the gas vapours was seen to change depending on the composition used to form the sensing layer. For example, sensor S4 was formed using PVB and 1.5 wt.% carbon black and displayed a higher response to 5000 ppm propanol (43.27) than that to toluene (19.43). While the response of S3, with a sensing layer composed of 75/25% Fe2O3/MnO2 and 5 wt.% PVB binder and 1.5 wt.% carbon black to the same concentration of propanol and toluene at room temperature was 62.57 and 45.95%, respectively.