Nanocrystalline Manganese Substituted Nickel Ferrite Thick Films as PPM Level H2S Gas Sensors

A simple sol-gel auto combustion technique is introduced for the synthesis of nanocrystalline manganese substituted nickel ferrite dry powders. These dry powders were mechano-chemically mixed with organic binders to prepare thixotropic pastes. Thixotropic pastes of as prepared ferrite powders were formulated and screen printed on glass substrates to form thick films, followed by firing at 450oC. The crystal structure, phase, surface morphology and topography of the samples were characterized by X-ray diffraction study, scanning electron microscopy, transmission electron microscopy, etc. The gas sensing behavior of the samples were characterized by exposing the films to various inflammable and toxic gases like LPG, NH3, CO2, ethanol, H2S and Cl2. It was found that the sensors made from the composition containing x=1.0, exhibits highly selective and most sensitive towards 20 ppm of H2S gas at 3500C. The effect of operating temperature, gas concentration, type of gases, etc. on gas response were studied and discussed. DOI: 10.17762/ijritcc2321-8169.15082