Indexed on: 01 Sep '99Published on: 01 Sep '99Published in: Journal of Materials Science: Materials in Electronics
FeSbO4-based semiconducting ceramics used as a promising candidate for sensing liquid-petroleum gas (LPG) are presented here for the first time. Precursor powders of FeSbO4 were prepared by two different methods (i.e., ball-milling and chemical coprecipitation). The solid-state reaction in the Fe2O3-Sb2O3 system was investigated by means of thermal gravimetric-differential thermal analysis (TG-DTA) and X-ray diffraction (XRD). Based on our experimental results and previous work, the diffusion of antimony oxide onto α-Fe2O3 is assumed to be a controlling step of the solid-state reaction. Scanning electron microscopy (SEM) and the BET method were used to characterize the samples calcined at 550 to 1000 °C. It was found that a sudden change in specific surface area, crystallite size and particle size takes place between 550 °C calcining and 600 °C calcining, which has an obvious influence on gas-sensing properties. FeSbO4-based sensors operating at 370 °C show a high sensitivity and selectivity to liquid-petroleum gas (LPG) over H2 CO or i-C4H10. Addition of Pd shows a fair increase in sensitivity to LPG, but a remarkable improvement in response and recovery times which is advantageous for its practical application.