Ammonia gas sensor based on a spinel semiconductor, Co0.8Ni0.2Fe2O4 nanomaterial

Thick film of nanocrystalline Co0.8Ni0.2Fe2O4 was obtained by sol-gel citrate method for gas sensing application. The synthesized powder was characterized by X-ray diffraction (XRD) and transmission electron microscopy. The XRD pattern shows spinel type structure of Co0.8Ni0.2Fe2O4. XRD of Co0.8Ni0.2Fe2O4 revels formation of solid solution with average grain size of about 30 nm. From gas sensing properties it observed that nickel doping improves the sensor response and selectivity towards ammonia gas and very low response to LPG, CO, and H2S at 280 A degrees C. Furthermore, incorporation of Pd improves the sensor response and stability of ammonia gas and reduced the operating temperature upto 210 A degrees C. The sensor is a promising candidate for practical detector of ammonia.