WO3-Based Glass-Crystalline Sensor for Selective Detection of Ammonia Gas

In this study, WO3-based glass-crystalline material from the WO3-ZnO-La2O3-Al2O3 system, containing high amount of tungsten oxide was synthesized by melt-quenching technique. The sol-gel technique was used to prepare the glass powder which was then dispersed in an organic solvent to make a printable ink. The latter afterwards was screen-printed as a thick film on an alumina substrate having interdigitated platinum electrodes in order to be used as a gas sensor. The fabricated material was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and thermo-gravimetric analysis (TGA). The sensitivity of the prepared sensor was noticeably high at low concentrations of NH3 at different temperatures. Moreover, the sensing film was selective as there was no response toward both CO2 and CH4 at the same conditions.