Porous spinel-type oxide semiconductors for high-performance acetone sensors

Spinel-type semiconductor compounds represent an alternative for robust and inexpensive detection systems, due to their good thermal and chemical stability in operation. The sensing mechanism is based on the change in electric resistivity when exposed to specific gaseous ambient, resulting from chemical reactions between metal-oxide surface and gas molecules. Sample composition and morphology are key factors in determining the selectivity and sensitivity of solid-state sensors. In this work structural, morphological and sensory characteristics of some porous oxide semiconductors with spinel-type structure (Ni0.99Co0.01Mn0.02Fe1.98O4-delta, Li0.5Sm0.1Fe2.4O4 and Mg0.9Sn0.1Fe2O4) are presented. The self-combustion technique was used to prepare these compounds. This method offers the advantage of obtaining nanosized reproducible and porous ceramics with high specific surface area and exact stoichiometry. Investigated compounds hold promise for high-performance applications in acetone sensors.