Selective detection of NH3 by Ag6Mo10O33 thick film by AC impedance spectroscopy

An ammonia sensor based on Ag 6 Mo 10 O 33 thick film was fabricated and tested. The morphology of the film was characterized by SEM. The electrical capacitance and impedance of the compound were investigated by exposing the film in air, air containing 500 vppm of H 2 , petroleum gas (PG) and NH3 independently at 350°C using AC impedance spectroscopy. When the film was exposed to air containing ammonia significant increase in capacitance was observed at lower frequencies. The mechanism for the changes in capacitance and impedance as a function of frequency is presented.