Tunable formation of nanostructured SiC/SiOC core-shell for selective detection of SO2

• Published in: Sensors and actuators. B, Chemical Vol. 305; p. 127485
• Main Authors: Gaiardo, A., Fabbri, B., Giberti, A., Valt, M., Gherardi, S., Guidi, V., Malagù, C., Bellutti, P., Pepponi, G., Casotti, D., Cruciani, G., Zonta, G., Landini, N., Barozzi, M., Morandi, S., Vanzetti, L., Canteri, R., Della Ciana, M., Migliori, A., Demenev, E.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.02.2020; Elsevier Science Ltd
• Subjects: Chemical activity; Chemoresistive gas sensor; Functional materials; Gas sensors; Gravimetry; High selectivity; Humidity; Nanostructure; Nanostructured SiC thick film; Organic chemistry; Photoelectrons; Selectivity; SiC/SiOC core-shell; Silicon carbide; SO2 detection; Substrates; Sulfur dioxide; Thick films; High selectivity; SiC/SiOC core-shell; Chemoresistive gas sensor; SO2 detection; Nanostructured SiC thick film
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.127485

[Display omitted] •The surface reactivity and chemoresistive properties of nanostructured SiC can be thermo-activated under proper condition.•SiC nanopowder resulted to be an extremely selective functional material for the detection of SO2, both in dry and wet air.•The surface reactivity of SiC nanoparticles vs. SO2 is promoted by the SiC-SiOC core-shell formation, at high temperatures. Silicon carbide is a well-known material with high thermal, mechanical and chemical stability. These properties have allowed, over time, its wide use as an inert material to be employed as a substrate or support in different applications. In this work, we demonstrate that, under proper conditions, it is possible to activate the chemical reactivity of nanostructured SiC, which can be employed for chemoresistive purposes. With this aim, a commercial powder of SiC has been characterized from a morphological, structural and thermal point of view. Then, screen–printed thick films were obtained from SiC powder and thus tested as a functional material for chemoresistive gas sensors, in thermo-activation mode. The samples were exposed to 13 gases with important chemical differences. Analyses showed that SiC is an extremely selective functional material for the detection of sulphur dioxide (SO2) in concentrations within the ppm range. This interesting result was found at high working temperatures (600−800 °C), useful for harsh environments, and the measurements proved to be completely free from humidity negative interference. Thermo-gravimetric and X-ray photoelectron spectroscopy characterizations highlighted that the high selectivity of the SiC layer is promoted by the thermal formation of a SiC/SiOC core-shell, tunable by controlling temperature and humidity parameters. An interpretation of the gas sensing mechanism occurring between SO2 molecules and SiC/SiOC core-shell has been proposed. The unexpected chemical activity, identified for nanostructured SiC, can be exploited for the specific detection of SO2, since this gaseous compound plays an important role in air pollution, industrial processes and winemaking.